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Full text of "Evaluation of adhesive binders for the preservation of in-situ aboriginal surface finishes at Mesa Verde national park"

university 

pennsylvania. 

LIBRARIES 




EVALUATION OF ADHESIVE BINDERS FOR THE PRESERVATION OF 

IN-SITU ABORIGINAL SURFACE FINISHES AT 

MESA VERDE NATIONAL PARK 



Rebecca J. Carr 



A THESIS 



Historic Preservation 



Presented to the Facilities of the University of Pennsylvania 
in Partial Fulfillment of the Requirements for the Degree of 

MASTER OF SCIENCE 



2002 



\j^M^o 



Supervisor 

FranK-o. Matero 

Associate Professor of Architecture 




InA^^^O 



GradtfaTe \3roup Chair 

FranlcS-Matero 

Associate Professor of Architecture 



Reader 

Kathleen Fiero 
Stabilization Archeologist 
Mesa Verde National Park 
National Park Service 



^no£ f^T^/roA )o"2> |S0O3 IcM\ 



UNIVERSITY 
OF 

PENNSYLVANIA 
LIBRARIES 



ACKNOWEDGEMENTS 

I wish to thank everyone who contributed to this work. Each of you has helped 
me to combine my guiding interests in art and archeology. Without all of your kindness, 
patience and knowledge I could never have done this. Your contributions and 
encouragement will be remembered. I especially want to thank the following individuals: 
Kathy Fiero and Frank Matero for their sharing their guidance and knowledge; Larry 
Nordby for his support while I conducted this research; Ellen Raiselis and Robert 
Schetgen for their editing and encouragement; Mary Griffitts for her knowledge of Mesa 
Verde geology; Paul Rogers, Deb Jenson, Liz Baur, Carolyn Landes, Victoria Atkins and 
Susan Thomas for allowing me access to archeological project reports; Angelyn Rivera 
and Mary Slater for providing knowledge and training, David Dyes for providing me with 
complimentary samples of the Rhoplex products analyzed in this thesis, Sally Cole for 
her insight into traditional aboriginal practices; Alex Radin for helping me to conduct 
mechanical testing at the Materials Testing Lab, Urs Mueller for providing laboratory 
analysis, Terry Klein, Meta Gennowitz, George Miller and Steve Tull for supporting my 
efforts toward continued education despite the effect that this had on my work schedule, 
Ed Morin, Ingrid Webber and Rick Affleck for sharing their personal libraries, Maribel 
Beas for providing references and advise on mechanical testing methods; Richard 
Raisellis, , Cindy Macintosh, Suzanne Carol Don Schmidt, Doug Ramsey and Lee Jong 
for their technical advice; Mesa Verde's Architectural Documentation Crew for sharing 
for sharing their knowledge; Suzanne Hyndman for helping me to submit this thesis long- 
distance from Colorado. 



TABLE OF CONTENTS 

1. INTRODUCTION 1 

2. RESEARCH OBJECTIVES 4 

2.1 Research goals 5 

3. PRINCIPLES OF ADHESION 6 

3.1 Introduction to Earthen Surface Finish Technology 9 

3.2 Mesa Verde Aboriginal Surface Finishes 12 

4. PRIOR SURFACE FINISHES RESEARCH AT MESA VERDE 16 

4.1 Materials Characterization of Soils and Surface Finishes 21 

4.2 Mortar Analysis 22 

5. PARTICLE SIZE ANALYSIS OF STABILIZATION SOILS 28 

5.1 Pre-Sieved Reddish Brown Stabilization Soil Sample (SY-3) 29 

5.2 Yellow /Very Pale Brown Stabilization Soil Sample (SY-2) 31 

5.3 Test for Salts 35 

5.4 Chemical Testing for Calcium Carbonate 37 

5.4.1 Test for Calcium 37 

5 .4.2 Test for Carbonates 40 

6. PREPARATION OF SAMPLES WITH UNIFORM THICKNESS 42 

6. 1 Substrate Porosity 46 

6.2 Relative Shrinkage of Reproduction Surface Finishes 48 

6.3 Relative Water Absorption of Reproduction Surface Finishes 49 

7. ACCELERATED WEATHERING - PRELIMINARY TESTING 52 

7.1 First Cycle 52 

7.2 Second Cycle 52 



7.3 Third Cycle 52 

8. ACCELERATED WEATHERING OF REPRODUCTION FINISHES 56 

8.1 First Cycle 57 

8.2 Second Cycle 57 

8.3 Third Cycle 58 

8.4 Fourth Cycle 59 

8.5 Fifth Cycle 59 

9. BINDING AGENTS COMMONLY USED IN 

ADHESIVE, SEALANT, AND PAINT FORMULATIONS 64 

9. 1 Mineral Binders 64 

9.2 Plant Binders 65 

9.3 Wax Binders 67 

9.4 Alkyd Binders 68 

9.5 Acrylic Binders 69 

9.6 Animal Binders 70 

10. GELATIN BASED ADHESIVES 72 

11. CURRENT ADHESIVE TREATMENT METHODS 79 

11.1 Cold Gelatin Treatments 81 

1 1 .2 Warm Gelatin Treatments 82 

12. ANALYSIS OF ADHESIVE PERFORMANCE 83 

12.1 Viscosity Test 87 

12.2 Set Time Test 90 

12.2. 1 Glass Transition Temperature 92 

12.3 Reflectance Test 93 

12.4 Shrinkage of Solutions 97 

12.4.1 First Test for the Relative Shrinkage of Solutions 101 



12.4.2 Second Test for the Relative Shrinkage of Solutions 102 

12.5 Expansion, Contraction and Flexability of Adheisves 104 

12.5.1 Acrylic Solutions 1 04 

12.5.2 Unplasticized Gelatin Solutions 1 05 

1 2.5.3 Plasticized Gelatin Solutions 1 05 

1 2.5.4 Elasticity 1 06 

1 2.6 Adhesive Bond Strength 1 09 

12.7 Vapor Transmission Test 116 

12.7.1 Second Test for the Relative Shrinkage of Solutions 102 

12.8 Expansion, Contraction and Flexability of Adheisves 104 

12.8.1 Acrylic Solutions 104 

12.8.2 Unplasticized Gelatin Solutions 105 

12.8.3 Plasticized Gelatin Solutions 105 

12.8.4 Elasticity 106 

12.9 Adhesive Bond Strength 109 

12.10 Vapor Transmission Test 116 

13. REVERSABILITY 118 

14. CONCLUSIONS 122 

BIBLIOGRAPHY 128 

APPENDICES: 

APPENDIX A: List of Soil Samples and Collection Proveniences 143 

APPENDIX B: Porosity of Sample Substrates - Total Immersion Test 145 

APPENDIX C: Porosity of Sample Substrates - Hygrostatic Weighing Test.. 1 5 1 
APPENDIX D: Common Additives used in Gelatin Based Formulations 153 



APPENDIX E: Viscosity of Acrylic and Gelatin Adhesive Solutions 157 

APPENDIX F: Shrinkage Cracks formed on Reproduction Surface Finishes. 159 

APPENDIX G: Relative Absorption for Reproduction Surface Finishes 165 

APPENDIX H: Cohesive Strength of Gelatin Based Adhesive Formulations. 167 

APPENDIX I: Adhesive Bond Strength of Treated Samples 174 

APPENDIX J: Water Vapor Transmission Rate of Treated Samples 178 

APPENDIX K: Modern Extruded Brick; Reddish Brown Plaster 

with a Reddish Brown Wash Accelerated Weathering - Preliminary Testing. 187 

APPENDIX L: Modern Extruded Brick; Reddish Brown Plaster 
with a White Wash; Weathered Samples - Not Treated 189 

APPENDIX M: Modern Extruded Brick; Reddish Brown Plaster 

with a White Wash; Weathered Samples - Treated 191 

APPENDIX N: Modern Extruded Brick, Reddish Brown Plaster 

with a Reddish Brown Wash; Weathered Samples - Treated 212 

APPENDIX O: Modern Extruded Brick; Reddish Brown Plaster 

with a Reddish Brown Wash; Weathered Samples - 

Digital Condition Maps 240 



APPENDIX P: Rohm and Haas Product 

Performance Specification Sheets 250 

APPENDIX Q: Rohm and Haas Product 

Materials Safety Data Sheets 259 

INDEX 269 



LIST OF TABLES 

Table 1. Sand:Silt/Clay Ratios for Earthen Surface Finishes 16 

Table 2. Particle Size Distribution for Reddish Brown Plaster Samples 18 

Table 3. Soil Samples used to Formulate White Finishes 21 

Table 4. Particle Size Analysis for Reddish Brown Samples 24 

Table 5. Particle Size Analysis for Light Brown Samples 24 

Table 6. Particle Size Analysis for Acid Treated Soil Samples 25 

Table 7. Acid Soluable Fraction Determined by Mortar Analysis 27 

Table 8. Comparison of Results for Wet Chemical Mortar Analysis 26 

Table 9. Particle Size Analysis for Yellow/Very Pale Brown Soil Sample 31 

Table 10. Particle Size Analysis - Very Pale Brown Soil Sample 32 

Table 1 1 . Sand.Silt Ratio for Very Pale Brown Soil Sample 34 

Table 12. Particle Size Analysis - Reddish Brown Soil Sample 30 

Table 13. Particle Size Analysis - Reddish Brown Soil Sample 30 

Table 14. Sand: Silt/Clay Ratio - Reddish Brown Soil Sample 33 

Table 1 5 . Qualitative Analysis of Salts 36 

Table 16. Chemical Spot Test Results for the Presence of Calcium 39 

Table 17. Chemical Spot Test to determine presence of Carbonates 41 

Table 18. Test to confirm the presence/absence of carbonates 40 

Table 19. Porosity of Substrates Determined by Hydrostatic Weighing 47 

Table 20. Test Results for Relative Shrinkage of Finishes 49 

Table 21. Observations for Preliminary Accelerated Weathering Test 54 



Table 22. Types of Commercially Available Gelatin 72 

Table 23. Viscosity of Treatment Solutions 88 

Table 24. Reflectance of Acrylics when applied to Surface Finishes 95 

Table 25. Test Data for Assessing Gloss/Reflectance 94 

Table 26. Comparison of Reflectance Ratings for Adhesive Formulations 95 

Table 27. Unrestrained Adshesive Shrinkage Cracks 96 

Table 28. Shrinkage Observations for White Wash Sample #4 97 

Table 29. Test Data for Volumetric Shrinkage Test 1 03 

Table 30. Bond Strength for Retreatment of Adhesives 107 

Table 3 1 . Comparison of Bond Strength for 5% Formulations 114 

Table 32. Comparison of Bond Strength for 10% Formulations 114 

Table 34. Average Water Vapor Transmission Rates 1 17 

Table 35. Water Vapor Transmission - Summary of Test Data 1 17 



Chapter 1 
INTRODUCTION 

Archaeologists attribute the architecture of Mesa Verde National Park to Ancestral 
Puebloan people who constructed and inhabited these structures prior to A.D. 1300. At 
this time, sandstone masonry structures coated with earthen plasters were constructed at 
more than 600 sites within the modern day boundaries of Mesa Verde National Park. 

Mesa Verde contains a high percentage of its original earthen surface finishes. These 
earthen renderings are interpreted to the public on a daily basis. Earthen surface finishes 
contribute to both the informational value contained within a site and to the durability of 
these structures. At Mesa Verde, surface finishes were originally a part of building 
maintenance as well as a means for artistic, social and cultural expression. Today, 
prehistoric surface finishes play an important role in the maintenance and interpretation 
of these archaeological sites. Earthen finishes serve as a sacrificial layer applied to extend 
the life of an underlying masonry substrate and in doing so, these layers retain an 
interpretive value. Hand prints, anthropomorphic figures and geometric shapes decorate 
the walls of many rooms. Pictographs, color schemes, and analysis of finish layers 
contribute interpretive data regarding the use and history of Ancestral Puebloan 
architecture. 

Earthen surface finishes at Mesa Verde are an extremely important resource for 
archaeologists, scientists, managers, planners and the park's culturally affiliated tribes. 



These painted designs hold significance for the modern Pueblo people and should be 
preserved for the future generations of all Americans. 

As a National Park, Mesa Verde has been set aside as an important resource for 
future generations. It has been designated as a World Heritage Site, worthy of 
preservation, research and interpretation. As such, it is important to select methods of site 
stabilization that will prolong the life of this invaluable resource and enable us to conduct 
future research that will enhance our understanding of the materials used to construct 
these structures. Aside from tourism, it is the responsibility of the National Park Service 
to maintain these structures in their current state. Every year, fragments of earthen plaster 
detach from the walls. It is our responsibility to future generations to retain as much of 
this cultural resource as possible. 

Between 1994 and 1997, a documentation and treatment program for Earthen 
Surface Finishes was developed at Mug House in Mesa Verde National Park. A 
partnership between the University of Pennsylvania Architectural Conservation Lab and 
the National Park Service has produced a vast quantity of research regarding the 
mechanisms of surface-finish deterioration, low-impact methods for stabilization, and 
detailed documentation. Consultation with Native American tribes led researchers at the 
university to seek a natural adhesive as an alternate to the popular acrylics used to 
reattach and consolidate earthen surface finishes. 

The University of Pennsylvania Architectural Conservation Lab designed and 
implemented a documentation method to record and monitor each of the factors that 



contributes to a loss of earthen surface finishes at these sites. A total of 20 conditions 
terms were identified and each is documented on site before any treatments are 
conducted. 

The university also developed treatment methods to stabilize earthen surface finishes 
that are delaminated and detached from their substrate. One such treatment uses either of 
two gelatin solutions that are diluted with water to form an adhesive solution. This 
adhesive is injected into exposed voids to stabilize isolated areas of surface finish that are 
already blistered, delaminated or detached. These damaged finishes are in the most 
jeopardy of loss since blistering, delamination and detachment are the immediate 
precursors to the loss of finish layers. 



1 Personal communication with Frank Matero, University of Pennsylvania Architectural Conservation 
Laboratory, 7/23/02. 



Chapter 2 
RESEARCH OBJECTIVES 

This study seeks to evaluate the various methods of reattachment used at Mesa Verde 
by reproducing Ancestral Puebloan surface finishes and subjecting them to accelerated 
environmental conditions. By this process, a limited spectrum of the deterioration 
currently observed at Mesa Verde National Park was induced. To this purpose, 
documentary research and a modified model of experimental archeology have been 
combined with modern methods of materials testing. This study will provide additional 
information regarding the mechanisms and rate of deterioration currently observed at 
these archeological sites. 

Four adhesive solutions were selected for materials testing. The two gelatin based 
solutions currently used by the University of Pennsylvania were tested and compared 
against acrylic emulsions. The data generated by this research provides comparative data 
for evaluating the effectiveness of the current treatment methods and to provide 
additional research that will enhance the understanding of the treatments of these 
deterioration mechanisms. 

Soil samples were collected from Mesa Verde National Park to reproduce the 
prehistoric surface finishes found at archeological sites within the park. The formulation 
of these reproductions was based on prior research conducted at Mesa Verde. Loosely 
based on the principle of experimental archaeology, these small-scale reproductions were 
subjected to artificially induced accelerated weathering. Monitoring and conditions 

4 



recording throughout the weathering process enhanced my understanding of the sequence 
of symptoms and environmentally induced threats that lead to the deterioration of 
Ancestral Puebloan surface finishes. This knowledge will be used to further the 
conservation program at Mesa Verde National Park. 

2.1 Research Objectives 

• Assess the effects of particle-size distribution on the durability of earthen surface 

finishes 

• Assess the affects of accelerated weathering of surface finishes with a crystalline 

binder of calcium carbonate as compared to surface finishes with a clay binder 
alone 

• Compile laboratory methods from the fields of conservation and materials testing 

to produce testing recommendations for the further assessment of earthen surface 
finishes 

• Document the progression of accelerated deterioration of earthen surface finishes 

as a basis for in-situ monitoring of extant surface finishes at Mesa Verde 
National Park 

• Assess the physical properties of stabilization adhesives currently used at Mesa 

Verde National Park by researching adhesive formulations and materials testing 

• Conduct comparative materials testing of four different adhesive formulations 

• Provide recommendations for further study of the adhesive reattachment of 

earthen plasters 



Chapter 3 
PRINCIPLES OF ADHESION 

Adhesives, paints, plasters, mortars, fillers and sealants are formulated according to 
the mechanical properties of their constituents and the ways that each component 
interacts on a physical and chemical level. The strength and durability of an adhesive 
formulation is dependent on the physical properties of the adherents that it joins. Many 
adhesives do not attach to their adherents on a chemical level. Instead, much of the 
strength of an adhesive bond is dependent upon the ability of an adhesive to physically 
coat the surfaces to be adhered. When an adhesive and adherents have similar rates of 
expansion and contraction, when subjected to environmental fluctuations of temperature 
and relative humidity, their adhesive bond lasts longer. 2 Along the same lines, an 
adhesive with greater flexibility can move with the expansion and contraction of its 
adherents resulting in a more durable bond despite the stresses induced by such 
movement. 

Binding of particles together to form a layer of surface finish can be done in one of 
three ways. Pigment particles can be bound together mechanically and chemically, as is 
the case for plasters and true frescoes, where the particles are bound by a system of 
interlocking mineralogical crystal formations of calcite. Pigments can be bound by film- 
forming polymers that cross-link at the molecular level, known as chemical adhesion, or 



2 Berger, Gustav A. and William H. Russell. "Conservation of Paintings : Research and Innovations", 
Archetype Publications: London, 2000. 



by monomers and/or polymers that do not cross-link, but are instead held in close 
proximity to one another by electrostatic forces characterized as Van der Waals forces. 

Van der Waals forces are defined as follows "the physical forces of attraction and 
repulsion existing between molecules and which are responsible for the cohesion of 
molecular crystals and liquids. The forces stem partly from dipole-dipole, or dipole- 
induced-dipole interactions; however, even nonpolar molecules and atoms exert a certain 
attraction on one another. Van der Waals forces act only over relatively short distances, 
and are proportional to the inverse of the seventh power of the intermolecular distances." 3 

The deterioration of earthen surface finishes occurs in several different forms of 
adhesion loss. This loss is experienced at many levels. Loss of adhesion between particles 
within a single layer of finish constitutes a loss of cohesion and results in a friable surface 
in need of consolidation. Interfacial loss of adhesion between layers of finish results in 
"delamination". Loss of adhesion from the substrate is termed "detachment" and multiple 
isolated spaces of interfacial detachment accompanied by deformation are called 
"blistering". "Finish cracks" are the result of environmentally induced expansion and 
contraction; when one layer expands more than the adjacent layer to which it is still 
adhered. Rapid wetting and drying cycles induce differential shrinkage and swelling of In 
the case of the uppermost layer of surface finish, this movement causes stress between 
the unrestrained upper surface of the layer and the restrained lower surface that it is still 
adhered to. The build up of this stress eventually leads to the strain that causes a break in 
the cohesive strength between particles within the layer. Thus, cracks are due to 



3 Matt T. Roberts, Don Etherington and Margaret R. Brown. "Bookbinding and the Conservation of books: 
A Dictionary of Descriptive Terminology", Stanford University Libraries, 1994. 
http://palimpsest.stonford.edu/don/don.html 

7 



differential, environmentally induced, expansion and contraction of one layer when it is 
still adhered to a more rigidly bound structure. The strength of bonds between the 
particles of sand within the masonry, finish layers, and interfacial attraction have a 
substantial impact on the rate of earthen surface finish decay. 

The differential expansion and contraction that occurs when one layer is more prone 
to movement than its underlying layer causes stresses at the interface between these two 
layers. The build up of these stresses eventually causes the strain that results in the 
cracking and the blistering or buckling of one layer. Fluctuations in surface roughness 
and surface accumulations of soot or other oily substances provide areas of weakness 
where adhesion loss is prone to occur. Variations in layer thickness and particle-size 
distribution also create areas of weakness within the film where cracking is likely to 
occur. 

The amount of surface area that an adhesive is in contact with an adherent depends 
on the surface tension/viscosity of the adhesive solution, cleanliness of the adherent, the 
porosity/absorption of the adherent and its texture/surface roughness. The surface tension 
of an adhesive solution affects the rate that an adhesive flows when applied to an 
adherent. This property is measured as the viscosity of the solution. When a solution has 
low surface tension, it is described as a low viscosity solution and is more able to 
penetrate into the pores of an adherent. In cases like Mesa Verde, low viscosity also 
allows the adhesive to absorb into the masonry and plaster finishes, creating a thin film 
around the particles that make up each of these adherents. The ability of an adhesive to 
coat these particles is referred to as its wettability. Deposits on the surface of an adherent 



can reduce the wettability of even a viscous solution especially if the deposit is 
hydrophobic. Surface texture of adherents also affects the strength of an adhesive bond. 
Surfaces with measurable surface roughness and high porosity more readily retain both 
moisture and adhesives. Once an adhesive film has formed, its presence within these 
spaces provides a mechanical keying between the adhesive and adherent. 

3.1 Introduction to Earthen Surface Finish Technology 

Within European tradition, an abundance of fine arts paintings and architectural 
surface coatings were commonly engineered as a three-coat application. These historic 
plasters consist of an initial scratch coat, a secondary brown coat and a final finish coat. 
Using historical plaster applications as a model, the thin wash layers with different 
particle-size distribution might be the final applications of surface finish for a given 
scheme. Since surface finishes are periodically reapplied and because exposed surface 
finishes are subject to erosion, a combination of particle-size distribution to determine 
finish formulation and layer thickness measured on the microscopic level, is required to 
accurately interpret the sequence of aesthetic and maintenance requirements of a wall. On 
the broad scale, this will contribute information regarding the occupation sequence of 
individual rooms. 

Layering of surface coatings is a practical solution to increase the durability of such 
finishes. All materials expand and contract in response to atmospheric changes. Thermal 
and moisture expansion and contraction vary with the type of material that is subject to 
these changes. Factors that affect this movement are porosity, pore alignment, rigidity of 
internal structure, and surface permeability. The exteriors of buildings are subjected to 

9 



different temperature and humidity levels than the interiors. Depending on the depth and 
intensity of heat and moisture sources, wall surfaces experience differential contraction 
and expansion. 

The density and rigidity of materials used to construct a wall affect the expansion 
and contraction of each material. Layered surface coatings work as a system. The rigid 
substrate expands and contracts at a different rate than the upper layers. When the desired 
aesthetic effect is a smooth layer of surface finish, smaller silt and clay sized particles are 
required to achieve this effect. The underlying layer of plaster is formulated to contain a 
greater quantity of slightly larger sand particles. The larger quantity of sand sized 
particles makes this intermediate layer serve as a buffer between the aesthetically 
pleasing finish coat and the more rigid masonry substrate. 

In the short term, the engineering of Ancestral Puebloan plaster formulations 
contributed to the durability of these surface finishes at Mesa Verde. Yet it is not a 
perfect system. The engineering that has contributed to 800 years of durability is also 
what determines the current method of deterioration for these finishes. In order to achieve 
the smooth, refined aesthetic found in finish layers at Mesa Verde, a high percentage of 
silt and clay sized particles are used. Due to the size of these particles, the moisture 
activated expansion/contraction coefficient is high. The intermediate layer consists of 
more sand, which acts in the same manner as it would in a ceramic vessel. In ceramics, 
sand is added to the clay mixture as temper to reduce the shrinkage of pottery as it dries. 
In the formulation of surface finishes at Mesa Verde, the high sand content of mortars 
and plasters makes this tripartite system complete. The masonry provides a rigid substrate 

10 



that experiences little expansion and contraction. The mortar and subsequent plaster layer 
are formulated with higher amounts of silt and sand. Thus, they expand and contract less 
than the masonry. The finish layers of wash are made with a high quantity of smaller 
particles, making them expand and contract more than underlying plaster layers. 

In this way, the initial finish layers are formulated to shrink less than their overlaying 
counterparts. Stratified finish layer formulations beginning with a rigid substrate and 
ending with a wash that has a greater range of expansion and contraction, allows 
intermediate plaster layers whose range of movements is midway between that of the 
substrate and the wash to serve as a buffer between the two. As such the formulation of 
this plaster layer restrains the movement of the thinner wash layer. This restrain limits the 
amount of shrinkage cracks that occur during initial application of the wash layer, but 
also causes strain within the wash layer. The stress induced by restrained thermal and 
moisture coefficients of expansion eventually strain the finish layers to the point where 
they suffer deterioration from these forces. This deterioration occurs at the interfacial 
bond between layers when one layer moves faster than the other causing shear stresses at 
the interface between layers. 

When the cohesive forces of attraction between particles within a finish layer are 
stronger than the adhesive forces from one layer to the next and this attraction holds the 
particle in a rigid structure, environmental stresses cause interfacial cracking. If the same 
forces were acted upon a flexible structure, the particles would be able to slide over one 
another instead of cracking. In the case of the clay binders used at Mesa Verde, water 
serves as a plasticizer between the clay particles making them more flexible. Yet, when 

11 



the water evaporates, the structure becomes more rigid and slight environmental changes 
now induce enough stress to crack this rigid structure. 

3.2 Mesa Verde Ancestral Puebloan Surface Finishes 

Surface finish analysis at Mug House and at Cliff Palace show consistencies in the 
formulation of particle-size ratios. The same principle of rigid primer and flexible 
overlayer applies. At Mesa Verde, the primary binder is the clay sized particles and 
microcrystaline calcite. When these finishes were originally applied, they may have had 
additional organic binding media. Yet the predominant binding agent visible today is the 
clay fraction. According to ethnographic observations 4 , traditional Hopi builders applied 
surface finishes by smoothing them onto the wall with pieces of sheepskin. By wiping a 
hand or sheepskin over the wall, a smooth surface is formed as the plate-like particles of 
clay are aligned parallel to the surface of the wall. The more closely packed the clay 
particles are, the more dense and less permeable the finish layer becomes. In cases where 
the clay particles are chemically inert, clay particles are held together by electromagnetic 
forces alone. 

To better understand the potential for similar studies at Mesa Verde, two different 
materials were used to formulate reproduction plasters. In her thesis, Dix notes that two 
hues of white finish are present at Mug House. She states that "the white band in Kiva C 
is translucent and bright white, while the white upper field in Room 28 is opaque and has 



4 Personal communication with Sally Cole, Archeologist surveying the iconography of Rock Art at Mesa 
Verde, 3/4/2002. 

12 



a yellowish cast." 5 Dix attributes this color difference to the thickness of paint layers. 
Further analysis conducted by the University of Pennsylvania attributes this color 
difference to the presence of gypsum in this "bright white" finish and the presence of 
calcium carbonate for the white finish with a "yellowish cast". While layer thickness 
does affect translucence, the experimental archaeology portion of this research produced 
additional data. Soil samples obtained from within the park were used to reproduce 
prehistoric plasters. Two samples of soft white stone were ground with mortar and 
pestle, then sorted according to particle size and combined to formulate a 10:90 
sand:silt/clay particle size distribution. They were then wetted and applied to a base coat 
of reproduced reddish brown plaster formulated with 60:40 sand:silt/clay particle size 
distribution. The resulting plasters were classified according to Munsell color. The 
result was reproduction plasters that simulate the description noted by Dix. 

Based on limited data generated by the Slater 6 and Dix 7 surveys, it is difficult to 
ascertain whether particle-size distribution was consciously modified to produce more 
durable surface treatments. With further analysis, it would be interesting to explore 
whether particle size in plaster formulation is simply a product of access to materials as 
has been suggested by Mary Griffitts or if it is the product of technological innovations. 
The sourcing of materials for mortar samples led Griffitts to river drainages as a source of 
materials because this was where the mixture of materials was found. This leads us to 
theorize that either the source of materials was drainages where erosion had deposited 



5 Dix, Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from 
Mug House, Mesa Verde National Park Colorado" 1996, p. 95. 

6 Slater, Mary E. "Characterization of earthen architectural surface finishes from Kiva Q, Cliff Palace, 
Mesa Verde National Park Colorado", University of Pennsylvania Masters Thesis, 1999. 

13 



many different types of soils or that the soils were gathered from their formational 
sources and manually mixed to form the mortar mixtures used at Mesa Verde. Durability 
and aesthetic concerns affect the formulation of modern surface treatments, yet with 
modern methods of paint production and distribution many amateur painters are not 
familiar with the formulation of the paints that they apply. Prehistoric people did not have 
the luxury of modern methods for mass production. Thus, it makes sense that prehistoric 
paint formulation held an empirical basis that was passed on from generation to 
generation. 

Traditional surface finishes have utilized a number of different binding mediums. 
Plant, mineral and animal based binders have been used to produce surface coating since 
ancient times. Different names were given to specific paint formulations and these names 
are not always consistent from one author to the next. Many combinations of mineral, 
plant and animal proteins were used as surface finishes and to create architectural reliefs. 
Because these materials are film forming when used in certain combinations, they have 
been used in paintings, photography and wall finishes. Many of these materials are 
activated by exposure to temperature and moisture changes. Adhesive binders of animal 
or plant origin generally have a polymeric structure. These polymers form films by either 
condensation polymerization or addition polymerization. However, the crosslinking of 
these natural polymers occurs by addition polymerization. 8 An abundance of traditional 
formulations uses these polymers as a binding medium combined with either clay or 



7 Dix, Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from 
Mug House, Mesa Verde National Park Colorado" 1996. 

8 Wilks, Helen et al. Science for Conservators: Adhesives and Coatings, Volume 3, Conservation Unit of 
the Museums & Galleries Commission and Routledge, 1992. 

14 



calcium carbonate for the functional use of pigment, temper, filler and bulking agent. 9 
Further discussion of the binding agents used to formulate surface finishes is provided in 
chapter 9 of this study. 



9 Thornton, Jonathan. "A Brief History and Review of the Early Practice and Materials of Gap-Filling in 
the West", Journal of American Institute for Conservation 1998, Volume 37, Number 1, Article 2, p. 3-22. 

15 



Chapter 4 
PRIOR SURFACE FINISHES RESEARCH AT MESA VERDE 

Prior surface finish studies were cited as background research for the formulation 
of reproduction plasters. At the macroscopic level, separation of one layer from the next 
is difficult and often results in the contamination of one layer by the next. However, 
microscopic measurements have determined a different particle size distribution within 
mortars and layers of earthen surface finish. The University of Pennsylvania defines 
plasters as finishes measuring more than 1 mm. Thick. The historic term wash is used for 
layers of finish that measure less than 1 mm. thick. Although further research on this 
subject must be obtained to support this conclusion, a survey of current literature on this 
subject suggests that particle size is also related to film thickness. Though not easily 
assessed in the field, from a technological perspective, particle size may be a better way 
to define the difference between plaster and wash. Yet, the technological and theoretical 
use of materials by different social groups may have changed from site to site. 

A survey of previous mortar and surface finish analysis was conducted and 
confirmed by the author. This survey included analysis of samples of prehistoric Mesa 
Verde mortars, plasters and washes obtained from Mug House, Spruce Tree House, Cliff 
Palace and Square Tower House. The results of this survey showed a minor variation 
between the particle size of mortars and plasters, and showed a large difference between 
the sand: silt/clay ratio for wash layers from the ratio for plaster layers. The mathematical 
mean of particle size recorded in these studies and the combined mode for both studies 

are listed in table 1 . 

16 



TABLE 1 
Sand:Silt/Clay Ratios for Earthen Surface Finishes at Mesa Verde 



Study 


Dix, 1996 


Slater, 1999 


Mode Ratio 


Site 


Mug House Kiva C 


Cliff Palace Kiva Q 


Combined Studies 


Plaster 


54:46 


52:48 


60:40 


Wash 


32:68 


16:94 


10:90 



Slater measured the particle size distribution of plaster layers, defined by layer 
thickness, from the analysis of five samples. 10 The particle size mathematical mean for 
these plasters is 52% sand to 48% silt and clay size particles. With the exception of a tan 
colored plaster only found in sample 11, all plasters were of a buff color. All other 
particle size distributions for wash layers measured less than or equal to 5% sand sized 
particles. It is notable that this buff plaster is the most common color used in Cliff 
Palace. It may be common for premixed quantities of this plaster to be on hand while 
additional structures were being constructed. 

The mean values for particle size distributions in Kiva C of Mug House is based 
on four samples containing data for a total of 11 plaster layers and 27 wash layers. 11 
Similar to an anomaly found in the Slater data regarding buff colored plaster, Dix 
recorded higher variation in the granulometry in Mug House Kiva C as well as in thin 
layers of "Orange/Brown" surface treatments using the same formulations for wash 
layers as were used for plaster layers. Taking this into consideration, the ratio of sand to 



10 Slater, Mary E. "Characterization of earthen architectural surface finishes from Kiva Q, Cliff Palace, 
Mesa Verde National Park Colorado", University of Pennsylvania Masters Thesis, 1999, p. 102-106. 
" Dix, Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from 
Mug House, Mesa Verde National Park Colorado" 1996, p. 142-147. 

17 



silt and clay particles would drop to 22% sand and 88% silt and clay. Additionally, Dix 
analyzed an "Orange/Brown" colored mortar sample from Room 28 at Mug House and a 
soil sample obtained from the Adobe Cave. Particle size distribution for the mortar 
sample was 60% sand and 40% silt and clay sized particles. The soil sample exhibited a 
distribution of 95% sand with 5% silt and clay. 12 

It was determined at the outset of this project, that limited materials data was 
needed to confirm the findings of prior surveys. Since prior studies are the basis for this 
research, only a bulk gravimetric characterization of plaster samples was obtained with 
samples from samples obtained at Square Tower House. Preservation of original fabric 
was deemed more important than specific data acquired through triangulated point 
proveniencing of surface finish samples. Therefore, samples were obtained non- 
destructively by collecting spalls that had already naturally detached from their substrate. 
Consequently, provenience information is limited to the room from which they were 
collected. This collection strategy does not provide the level of detailed provenience 
information needed for full surface finish analysis. Since full surface finish analysis is not 
the purpose of this study, this method of sample collection provided suitable data for a 
comparison to bulk gravimetric analysis noted by Dix. A comparison of bulk gravimetric 
particle size analysis is provided in table 2. Additional characterization of original 
plasters is interspersed as a reference for comparison to the stabilization soils used in this 
study. 



12 Dix, Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from 
Mug House, Mesa Verde National Park Colorado" 1996, p. 148. 

18 



TABLE 2 
Comparison of Particle Size Distribution for Reddish Brown Plaster Samples 



Sieve 
Number 


Diameter 


Square Tower House 

5MV650 

KivaD 

(Carr, 2002) 


Mug House Kiva 
5MV1229C 
Plaster 
(Dix, 1996) 


Mug House Room 
5MV122928 
Mortar 
(Dix, 1996) 


8 


2.36 mm 


0% 


0% 


3% 


16 


1.18mm 


0% 


0% 


0% 


30 


600 Mm 


0% 


0% 


0% 


50 


300 Mm 


1% 


0% 


0% 


100 


150 Mm 


10% 


9% 


9.00% 


200 


75 Mm 


43% 


40% 


28% 


Fines / Pan 


NA 


46% 


50% 


57% 



The combined values for surface finish analysis from both the Dix and Slater 
studies yielded a modal average of 60% fine sand with 40% silt and clay particle size for 
earthen plasters and 10% fine sand combined with 90% silt and clay particle size for 
earthen washes. A variety of colors were recorded and both studies noted the presence of 
calcium in their samples. 13 This is not surprising since the use of calcium carbonate 
(lime) and calcium sulfate (gypsum) have been used in the manufacture of mortars and 
surface finishes from prehistoric times to modern day construction. Furthermore, of the 
four surface finish samples subjected to x-ray diffraction in the Getty study three of the 



Slater, Mary E. "Characterization of earthen architectural surface finishes from Kiva Q, Cliff Palace, 
Mesa Verde National Park Colorado", University of Pennsylvania Masters Thesis, 1999, p. 49. & Dix, 
Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from Mug 
House, Mesa Verde National Park Colorado" 1996, p. 95. 

19 



samples indicated the presence of calcium and no gypsum, while testing of the fourth 
sample revealed the presence of gypsum with only trace evidence of calcium. 14 

One color that was consistently formulated in both the study of Mug House Kiva 
C and Cliff Palace Kiva Q was the white wash. When studying the materials in Ancestral 
Puebloan white surface finishes, Watson Smith identified a binder of kaolin and/or other 
silicacious soils mixed with a ground pigment of either gypsum or calcium carbonate. 15 
Samples of white kaolinite, calcium carbonate, and a white sandstone from the Menefee 
formation were obtained at Mesa Verde for this study. 16 (see table 3) The sample of 
calcium carbonate deposit (see figure 1 ) was selected to reproduce the white wash used in 
this study. For comparative purposes, the sandstone sample was also subjected to 
materials testing. 

Every layer of white wash in the Mug House and Cliff Palace studies were 
formulated with 5-10% sand and 90-95% silt and clay sized particles. The only variation 
in particle size between these studies indicated that the Mug House Kiva C white washes 
consistently contained 5% more sand particles than the white washes used at Cliff Palace. 



14 Mueller, Urs. "Final Report", The Getty Conservation Institute. Los Angeles, CA, 1 1/29/2001 . 

15 Smith, Watson. "Kiva Mural Decorations at Awatovi and Kawaika-A", Appendix A: Analyses of the 
Component Materials of Pueblo Mural Paintings . Peabody Museum, Cambridge, MA, 1952, p.34. 

16 Roch identifications made by personal communication with Mary Griffitts, Geologist, 5/16/2002. 

20 



TABLE 3 
Mesa Verde Soil Samples used to Formulate White Surface Finishes 



Sample Name 


MR-1 


SY-1 


Description 


White deposit of kaolinite 


Caliche deposit on yellow 
sandstone 


Sampling Location 


Mile Marker 12.5 of Main 
Park Road 


Mesa Loop, Balcony House 


Material Color 


7.5YR8/1 White 


10YR8/2 White 


Soluble Salt Content 


Not Tested 


70% Carbonate content 


Resulting Plaster Color 


7.5YR8/1 White 


2.5YR8/2 Pale Yellow 



4.1 Materials Characterization of Soils and Surface Finishes 

Petrographic analysis of materials used to formulate Mesa Verde's original 
earthen mortars was conducted by geologist Mary Griffitts. She concluded that the soils 
used for both mortars and plasters at Mesa Verde were likely obtained form local sources 
within the park. 17 Local soils have been used by park staff in the periodic stabilization of 
structures since 1906. 18 Four different colored stabilization soils are currently used at 
Mesa Verde. These materials are not consistently obtained from the same location, so 
the particle size distribution and other soil characteristics may vary from one delivery to 
the next. The primary soils used in this study were obtained from the stabilization crews' 
supply. The four stabilization soils used at Mesa Verde during this study are (1) a red 
soil collected from Weatherill Mesa, (2) a yellow soil obtained locally from a quarry on 
the adjoining Ute Reservation, (3) white caliche obtained from road cuts in the vicinity of 



17 Nordby, Larry and Mary Griffitts. "Cliff Palace Building Materials Classifiaction and Selection", 
December, 1999. 

18 Personal communication with Kathy Fiero, stabilization archeololgist at Mesa Verde, 3/13/2002. 

21 



Balcony House and (4) commercially obtained quartz sand. Armed with this 
information, the soils were collected and characterized according to particle size 
distribution, acid solubility, salt content and Munsell color 20 . 

4.2 Mortar Analysis 

Positive results for a presence of calcium carbonates justified further testing to 
quantify the amount of acid soluble content contained within native soils versus the 
amount contained within original surface finishes. Wet chemical gravimetric mortar 
analysis was conducted according to the procedure outlined in Experiment #2 1 : Mortar 
Analysis: Simple Method as specified in Teutonico (1988). 21 




Figure 1 . Mortar analysis and substrate porosity testing at the University of Pennsylvania 



19 Personal communication with Kathy Fiero, stabilization archeololgist at Mesa Verde, 3/13/2002. 

20 American Society for Testing and Materials. "ASTM D1535-01 Standard Practice for Specifying Color 
by the Munsell System", 2001. http://www.astm. org/cgi-bin/SoftCart.exe/index.shtml?E+mystore 

21 Teutonico, Jean Marie. "ARC: A Laboratory Manual for Architectural Conservators", ICCROM, 1988, 
p. 113-116. 

22 



A single sample of each soil currently used by Mesa Verde's stabilization crew 
was tested. Former work conducted by the University of Pennsylvania has documented a 
distinct difference between the sand: silt/clay ratio used to produce a plaster from the 
sand:silt/clay ratio used to manufacture a wash at Mesa Verde. Thus, additional tests 
were conducted(see figure 1). A sample of prehistoric plaster that had spalled off the wall 
of Kiva C in Square Tower House was used for this test. 22 Tests were also run with silt 
fraction samples of both the yellow/very pale brown and red/reddish brown soils to 
approximate how much of the acid soluble material is contained within the silt fraction. 

A sample of each soil was weighed, then wetted with de-ionized water and 
hydrochloric acid. Observations were recorded as the acid-soluble fraction chemically 
reacted to form a gas. Once the reaction was complete, the fine portion and course 
portion of each sample were weighed to gravimetrically determine the percentage of acid 
soluble materials, the percentage of fine particles (see figure 2) and percentage of course 
particles (see figure 3). Mortar analysis test methods dictate that the course particles be 
further classified according to particle size. Since particle size distribution of non- 
chemically treated Reddish Brown soil was already determined according to ASTM D 
422-63(1998) Standard Test Method for Particle-Size Analysis of Soils, these results are 
displayed side by side for easy comparison (see tables 4, 5, and 6). 



22 Provenience attributed according to Mesa Verde Save America's Treasures Map: Brisben & Burnett 
2001. 

23 



TABLE 4 
Particle Size Analysis for Untreated and Acid Treated Reddish Brown Samples 



Sieve size 


Untreated Reddish Brown 
Soil Sample 


Treated Reddish Brown 

Soil Sample 


Sieve No. 


Diameter 


Weight Retained 


% Retained 


Weight Retained 


% 
Retained 


8 


2.36 mm 


0.00 g 


0% 


0.00 g 


0% 


16 


1.18mm 


0.00 g 


0% 


0.00 g 


0% 


30 


600 Mm 


0.00 g 


0% 


0.01 g 


0% 


50 


300 Mm 


3.44 g 


1% 


0.12 g 


1% 


100 


150 Mm 


59.61 g 


16% 


1.90 g 


10% 


200 


75 Mm 


67.46 g 


18% 


3.04 g 


15% 


Pan & Fines 


NA 


297.35 


64% 


13.35 g 


68% 


Acid Soluble 


NA 


NA 


NA 


NA 


5% 



TABLE 5 
Particle Size Analysis for Untreated and Acid Treated Light Brown Samples 



Sieve size 


Untreated Light Brown 
Plaster Sample 


Treated Light Brown 
Plaster Sample 


Sieve No. 


Diameter 


Weight Retained 


% Retained 


Weight Retained 


% 
Retained 


8 


2.36 mm 


0.00 g 


0% 


0.00 g 


0% 


16 


1.18mm 


0.00 g 


0% 


0.00 g 


0% 


30 


600 Mm 


0.00 g 


0% 


0.10 g 


1% 


50 


300 Mm 


1.47 g 


1% 


0.14 g 


1% 


100 


150 Mm 


15.32 g 


10% 


1.11 g 


6% 


200 


75 Mm 


65.71 g 


43% 


5.20 g 


26% 


Pan & Fines 


NA 


70.30 g 


46% 


11.63 g 


58% 


Acid Soluble 


NA 


NA 


NA 


NA 


8% 



24 



TABLE 6 



Particle Size Analysis for Acid Treated White and Light Brown Soil 


Samples 


Sieve size 


Treated White (SY-1) 
Soil Sample 


Treated Very Pale Brown 

Soil Sample 


Sieve 
Number 


Diameter 


Weight Retained 


% Retained 


Weight Retained 


% 
Retained 


8 


2.36 mm 


0.40 g 


2% 


0.00 g 


0% 


16 


1.18mm 


0.12 


1% 


3.10g 


16% 


30 


600 Mm 


0.01 


0% 


2.81 g 


14% 


50 


300 Mm 


0.01 


0% 


2.10 


11% 


100 


150 Mm 


0.02 


0% 


2.64 


13% 


200 


75 Mm 


0.03 


0% 


2.20 


11% 


Pan & Fines 


NA 


5.36 


27% 


4.60 


3% 


Acid Soluble 


NA 


NA 


70% 


NA 


32% 




Figure 2. Silt and clay fraction of the 
Reddish Brown Soil 



Figure 3. Fine grained sand particles 
magnified 500X 



Mortar testing confirmed that the white caliche contained more acid soluble 
material in its silt/clay fraction. Nearly 70% of the white caliche sample (SY-1) 
consists of acid soluble material. A majority of this acid soluble material is 
presumed to be the calcium carbonate identified in chemical spot testing conducted 
for this study. The quantity of acid soluble material in the white sample is in stark 
contrast to the 5% acid soluble content within the reddish brown soil sample while 
the acid soluble content of very pale brown soil was identified as an intermediary 
32% (see table 7). Based these results, two soils were selected to reproduce 

25 



earthen surface finishes. The white sample was selected to reproduce earthen 
finishes similar to those identified by Dix as having a microcrystaline calcite 
binder." The reddish brown soil was selected to reproduce earthen finishes 
identified by Smith as having a silicacious binder. 24 



TABLE 7 
Comparison of Results for Mortar Analysis by Wet Chemical Method 



Gravimetric Mortar Analysis -Chemical Method 




WiteSoil Very Pale Very Pale Lic/tBowi Fteddsh Raddsh 
BrovvnSIt BrowiSoil Plaster Brown Silt BrowiSoil 



% Coarse Fraction I % Fire Fraction D % Aad Sdiite Fraction 



23 Dix, Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from 
Mug House, Mesa Verde National Park Colorado" 1996. 

24 Smith, Watson. "Kiva Mural Decorations at Awatovi and Kawaika-A", Appendix A; Analyses of the 
Component Materials of Pueblo Mural Paintings , Peabody Museum, Cambridge, MA, 1952. 

26 



TABLE 8 
Acid Soluble Fraction Determined by Mortar Analysis by Wet Chemical Method 



Mortar Analysis: 
Wet Chemical 
Method 


Original 
weight 


Reaction: 

Visual 

Observations 


Fine 

fraction 

weight 


% Fine 
fraction 
Weight 


Coarse 

fraction 

weight 


% Coarse 

fraction 

weight 


% Acid 
Soluble 
Weight 


White Soil (SY-1) 


20.00 g 


Very strong, 
long term 


5.36 


26.80% 


0.59 g 


2.95% 


70% 


Very Pale Brown 
Silt (SY-2) 


20.00 g 


Very strong, 
long term 


13.68 g 


68.40% 


0g 


0% 


32% 


Very Pale Brown 
Soil (SY-2) 


20.00 g 


Very strong, 
long term 


4.3 g 


21.50% 


13.15 g 


65.75% 


12.75% 


Light Brown 
Plaster (SQT- 10) 


20.00 g 


Strong, long 
term 


10.99 g 


54.95% 


7.40 g 


37% 


8% 


Reddish Brown Silt 
(SY-3) 


20.00 g 


Clearly, but 
not long term 


18.93 g 


94.65% 


0g 


0% 


5% 


Reddish Brown 
Soil (SY-3) 


20.00 g 


Clearly, but 
not long term 


12.35 g 


61.75% 


6.07 g 


30.35% 


8% 



27 



Chapter 5 
PARTICLE SIZE ANALYSIS OF STABILIZATION SOILS 

Particle size analysis of the soils used in this study were conducted to establish a 
basis for reproducing the plaster formulations documented in surface finish analysis. 
Particle size was determined according to ASTM D422-63(1998) Standard Test Method 
for Particle-Size Analysis of Soils. Further basis for this procedure is contained within 
Experiment #18A: Particle Size Analysis: Part I / Sieving Procedure as specified in ARC: 
A Laboratory Manual for Architectural Conservators. 2 "' A Combustion Engineering 
Model RX-86 Sieve Shaker was used to sort each sample by particle size. 

The red and yellow soils used by the Mesa Verde stabilization crew are obtained 
in loose form while the white caliche (calcium carbonate) is collected as a weakly bound 
stone and then ground to produce soil of the desired particle size. Therefore, a sample of 
the Reddish Brown soil was characterized according to particle size distribution (see 
tables 9, 10, and 11), with only a sample of the yellow/Very Pale Brown soil being 
characterized as a basis for comparison (see figures 12, 13, and 14). Pretrographic 
analysis confirmed that the commercially graded stabilization sand is predominantly 
composed of well sorted quartz grains (see figure 4). This sand was not tested since it is 
used as an aggrgregate additive in mortar formulations and has no bearing on this study. 



25 Teutonico, Jean Marie. "ARC: A Laboratory Manual for Architectural Conservators", ICCROM, 1988, 

p. 73. 

28 




Figure 4. Photomicrographs of fine quartz sand particles displaying birefringence 

Particle size analysis revealed that the very pale brown soil was substantially 
better graded than that of the reddish brown soil. Since both soils were obtained from the 
Mesa Verde stabilization crew mortar and repointing supplies, the reddish brown soil 
may already have been sieved. It was immediately apparent that these soils were not 
properly graded for the reproduction of earthen surface finishes and would have to be 
modified in order to produce accurate facsimiles (see tables 9, 10, 11 and 12). 

5.2 Pre-Sieved Reddish Brown Stabilization Soil Sample (SY-3) 

Total bulk weight before sieving = 370.00 g. 

Weight of pre-sieved portion of soil sample = 193.86 g. 

Total bulk weight after sieving = 366.89 g 

Weight of post-sieved portion of soil sample = 192.48 g. 

Sand (diameter 2.36 mm. - 75 Mm.) = 130.51 g. 

Weight of suspended fines = 173.41 g. 

Silt/Clay (diameter < 75 Mm.) = 235.38 g. 

Munsell Color = 5YR5/4 Reddish Brown 



29 



TABLE 9 
Particle Size Analysis for Reddish Brown Soil Sample (SY-4) 



Sieve Number 


Diameter 


Weight Retained 


% Retained 


8 


2.36 mm 


0.0 g 


0% 


16 


1.18mm 


o.o g 


0% 


30 


600 Mm 


o.o g 


0% 


50 


300 Mm 


3.44 g 


1% 


100 


150 Mm 


59.61 g 


16% 


200 


75 Mm 


67.46 g 


18% 


Pan 


NA 


61.97 g 


17% 


Fines 


Suspension 


174.41 g 


47% 


Sand to Silt/Clay Ratio = 36:64 



TABLE 10 
Graphic Distribution of Particle Size Analysis - Reddish Brown Soil Sample 



Reddish Brown Soil - Particle Size Analysis 



(Wo 



16% 



65°/c 




18% 



Q>2.36 mm 

■ > 1.18mm 

□ >600 Mm 

□ > 300 Mm 

■ >150Mm 
B> 75 Mm 

■ <75Mm 



30 



5.1 Yellow/Verv Pale Brown Stabilization Soil Sample fSY-2^ 

Total bulk weight before sieving = 400.00 g. 

Weight of pre-sieved portion of soil sample = 265.6 g. 
Total bulk weight after sieving = 398.02 g. 

Weight of post-sieved portion of soil sample = 263.62 g. 
Sand (diameter 2.36 mm. - 75 Mm.) = 256.72 g. 

Weight of suspended fines = 134.4 g. 

Silt/Clay (diameter < 75 Mm.) = 141.3 g. 

Munsell Color = 10YR7/4 Very Pale Brown 

TABLE 11 
Particle Size Analysis for Yellow/Very Pale Brown Soil Sample (SY-2) 



Sieve Number 


Diameter 


Weight Retained 


% Retained 


8 


2.36 mm 


1.51 g 


0% 


16 


1.18mm 


62.21 g 


16% 


30 


600 Mm 


53.59 g 


13% 


50 


300 Mm 


45.21 g 


11% 


100 


150 Mm 


50.78 g 


13% 


200 


75 Mm 


43.42 g 


11% 


Pan 


NA 


6.9 g 


2% 


Fines 


Suspension 


134.4 g 


34% 


Sand to Silt/Clay Ratio = 64:36 



31 



TABLE 12 
Graphic Distribution of Particle Size Analysis - Very Pale Brown Soil Sample 



Very Pale Brown Soil - Particle Size Analys 


s 


13% 




11% /^^^ ^^\ 




/ m W ^\ 11% 




E> 2.36 mm 


/ \. ^ ^^^Sk 


■ > 1.18mm 


13%/ \. ^m ^^^ wk 


D>600Mm 


^J^^k I 


D> 300 Mm 


^^Mi^tik I 


■ >150Mm 


^^8 V 


'B>75Mm 


V V 


i«<75Mm 


16% ^B ^T 36% 




0% 





Based on information compiled from previous surface finish analysis studies, the 
high silt and clay content of this soil was not appropriate for unammended use as 
facsimile earthen plaster. Use of this soil without adding fine grained sand would result 
in shrinkage cracking and poor surface finish durability. This assertion was confirmed by 
the results of two accelerated weathering experiments. The accelerated weathering 
experiment described in chapter seven utilized soil formulations that were not based upon 
the results of prior surface finish analysis. These samples exhibited severe deterioration 

in only three weathering cycles. While the accelerated weathering experiment described 

32 



in chapter eight produced less deterioration after being subjected to four cycles of 
increasingly severe environmental fluctuations. Thus, it is safe to conclude that the 
Ancestral Puebloan surface finish formulations set forth in this study were intentionally 
formulated for durability. This assertion is also supported by the crushed aggregate 
particles identified microscopically." 6 The presence of crushed aggregate particles further 
indicates that Ancestral Puebloan earthen surface finish formulations were intentionally 
modified. 



TABLE 13 
Graphic Distribution of Sand:Silt/Ciay Ratio- Reddish Brown Soil Sample 



Reddish Brown Soil - Sand:Silt/Clay 

Ju iiik 36% 

64% ^B ^^ / 




□ > 75 Mm 
■ <75Mm 





26 Slater, Mary E. "Characterization of earthen architectural surface finishes from Kiva Q, Cliff Palace, 

33 



TABLE 14 
Graphic Distribution of Sand: Silt/Clay Ratio - Very Pale Brown Soil Sample 



Very Pale Brown Soil - Sand:Silt/Clay 



36°/c 




□ > 75 Mm 
■ <75Mm 



64% 



Particle size distribution, petrographic analysis, mortar analysis, chemical 
and elemental analysis each contribute valuable information when sourcing and 
subsequently reproducing the earthen surface finishes at Mesa Verde National Park. A 
survey of prior finish analysis provided specific formulations for the reproduction of 
these finishes. Conducting particle size analysis of local soils is the first step in mixing 
these surface finish formulations. Once the sand:silt/caly ratio of each soil was obtained, 
the sand fraction was separated from the silt fraction according to the procedure set forth 
in ASTM D422-63(1998). The silt/clay fraction of reddish brown soil measuring less 



Mesa Verde National Park Colorado", University of Pennsylvania Masters Thesis, 1999. 

34 



than 75 Mm in diameter, caliche deposits ground to the same sized silt/caly fraction and a 
fine quartz sand that measured between 75 Mm and 1 50 Mm were selected to mix the 
reproduction finish formulations set forth in this study. 
5.3 Test for Salts 

Six samples were tested for salts with Merckoquant © test strips. Each sample 
was prepared with one gram of sample combined with 2 cc. de-ionized water. The 
sample was mixed thoroughly then allowed to settle for 15 minutes before being 
subjected to the following tests: chlorid test strip #1.10079.001, nitrate test strip 
#1.10020.001, sulfate test strip 1.10019.000 and nitrate test strip 1.10020.000. After 
determining positive results for Nitrates, this experiment was followed with chemical 
tests as outlined in the procedures for Experiment #16: Qualitative Analysis of Water- 
Soluble Salts and Carbonates as specified in Teutonico (1988). 27 

The procedure was to place each of the test strips into the solution and allow them 
to dry. A reading was taken at 5 minutes to determine if chemical confirmation was 
required. The most common reaction after 5 minutes was a positive test for Nitrates. 
Thus, all samples were subjected to a chemical test for Nitrates. (Readings for strips 
must be calculated for grams per liter.) The chemical test for NO2" was to add two drops 
of dilute acetic acid (CH3COOH 2N) and two drops of Griess-Hosvay's Reagent. An 
intense pink color would indicate a positive reaction. Addition of zinc powder to the 
same solutions reduced NO3" to NOV thus producing the same positive reaction. Results 
for the above mentioned tests are provided in table 15. 



" Teutonico, Jean Marie. "ARC: A Laboratory Manual for Architectural Conservators", ICCROM, 1988, 
p. 58. 

35 



TABLE 15 

Qualitative Analysis of Salts 



Sample: 


EM 

Quant 

N0 2 


EM Quant 

N0 2 7 NO3 


EM Quant 
SO4 2 ' 


EM Quant 
CI" 


Chemical 
N0 2 


Chemical 
NO3 


Stabilization 
Sand 


Og/1 


-10 mg/1 


< 200 (-) 





- 


- 


White 

Sandstone 

Sand 


Og/1 


-10 mg/1 


< 200 (-) 









Reddish 
Brown Soil 
Sand 


Og/1 


-10 mg/1 


< 200 (-) 









Square 
Tower 
Plaster 


Og/1 


++/25 mg/1 


< 200 (-) 


500 mg/1 






Square 
Tower 
Sandstone 


Og/1 


-10 mg/1 


< 200 (-) 









Caliche 


Og/1 


-10 mg/1 


< 200 (-) 





- 


- 


White 

Sandstone 

Binder 


0.1 g/1 


-10 mg/1 


< 200 (-) 







+- 


Reddish 
Brown Soil 
Silt 


Og/1 


-10 mg/1 


< 200 (-) 









Weathered 

Red 

Plaster/Wash 


Og/1 


+/10mg/l 


>400 (+) 


500 mg/1 






Brick 

Substrate 


Og/1 


-10 mg/1 


< 200 (-) 


500 mg/1 







KEY: 

+- = concentration of the ion at the limit of perceptibility 

- = absence of the ion 

+ = presence of the ion 



36 



The presence of salts at Mesa Verde National Park contributes to the deterioration 
of earthen surface finishes. These salts are present in both the soils that are used to 
formulate original surface finishes and contained within the stones upon which these 
finishes are applied. Nitrates, sulfates and chlorides were found at varying amounts 
within the soils, stones and Ancestral Puebloan plaster finishes at Mesa Verde. These 
results are significant because the leaching of salts to the surface of masonry structures 
and the subsequent crystallization of these salts can rapidly accelerate the delamination 
and detachment of surface finishes (see figures 5 and 6). 




3jf ^ -v +*■ 3P *^ ■ 



Figure 5. Photomicrographs of salts formed on reproduction earthen finishes applied to a 
Mesa Verde sandstone substrate, shown at lOx, 20x and 40x magnification. 




Figure 6. Tide line of salts that have leached out of a sandstone sample obtained from 
Mesa Verde National Park 



37 



5.4 Chemical Testing for Calcium Carbonate 

Calcium carbonate is a water soluble salt that occurs naturally at Mesa Verde National 
Park. Similar in chemical composition to gypsum, identification of calcium carbonate in 
earthen surface finishes contributes to interpretations of the durability and technological 
application of Ancestral Puebloan surface finishes. 

Both calcium carbonate and gypsum have been identified in Ancestral Puebloan 
surface finish studies. 28 Further studies of this topic may contribute to the modern 
interpretation of Ancestral Puebloan surface finish application technology." 9 During this 
study, the author noted that calcium sulfate is considered to be more water soluble than 
calcium carbonate. 30 An additional solubility test was conducted with caliche samples 
obtained from Mesa Verde. After three weeks of soaking, a miniscule amount of material 
separated from the sandstone on which this white substance was deposited. Thus, it is 
suspected that the presence of gypsum prior to chemical spot testing was minimal. 

5.4.1 Test for Calcium 

A wet chemical spot test was selected that uses nitric acid and sulfuric acid to test 
for calcium. This was followed up with a test for carbonate using hydrochloric acid and 
barium hydroxide. 31 The test for calcium uses nitric acid to separate the calcium and 



28 Smith, Watson. "Kiva Mural Decorations at Awatovi and Kawaika-A", Appendix A: Analyses of the 
Component Materials of Pueblo Mural Paintings . Peabody Museum, Cambridge, MA, 1952. 

29 Vandiver, Pamela B., James R. Druzik, Jose Luis Galvan Madrid, Ian C. Freestone. George Segan 
Wheeler. "Materials Issues in Art and Archaeology IV", Materials Research Society: Symposium 
Proceedings. Volume 352, May 16-21, 1994, Cancun, Mexico, 1995. 

30 Jusko, Don A. "History of Painting Mediums... Glue, Wax Paint, Cera Colla, Mastic, Casein Paint, 
Fresco, Egg, Oil Paint, Acrylic Paint", mauigateway.com. 
http://www.mauigateway.eom/~donjusko/lmediums.htm#100.000 B/C 

31 Nancy Odegard, Scott Carrol and Werner S. Zimmt, Material Characterization Test for Objects of Art 
and Archaeology. Archetype Publications Ltd, 2000, p 100-103. 

38 



disperse it into a solution. Sulfuric acid combines with calcium ions to form gypsum 
crystals that are visible with the aid of a microscope (see figure 7). 

When calcium ions (Ca ^ are exposed to certain acids (HNO3 and H2SO4) they 
undergo the chemical reaction Ca 2+ (aq)+ S04 2 '(aq) -> CaSCV 2H2O (s) resulting in the 
formation of gypsum crystals (CaSCV 2H2O). Therefore, the chemical spot test used to 
determine the presence of absence of calcium is based on the formation of gypsum 
crystals after the sample has been chemically treated (see table 16). 



Table 16 
Chemical Spot Test Results for the Presence of Calcium 



Sample Name 


Munsell Color 


Test Result 


White Soil (SY- 1.1) 


10YR8/2 


Positive 


White Soil (SY- 1.2) 


10YR8/2 


Positive 


White Soil (SY- 1.3) 


10YR8/2 


Positive 


White Sandstone (MR- 1.1) 


10YR8/8 


Negative 


White Sandstone (MR- 1.2) 


10YR8/8 


Negative 


White Sandstone (MR- 1.3) 


10YR8/8 


Negative 


Reddish Brown Soil (SY-3.1) 


5YR5/4 


Positive 


Reddish Brown Soil (SY-3.2) 


5YR5/4 


Positive 


Reddish Brown Soil (SY-3.3) 


5YR5/4 


Positive 


Kiva D Pinkish White Plaster 
5MV650(SQT-10.4w) 


7.5YR8/2 overlaying 
7.5YR5/4 


Positive 


Kiva D Pinkish White Plaster 
5MV650(SQT-10.5w) 


7.5YR8/2 overlaying 
7.5YR5/4 


Positive 


Kiva D Pinkish White Plaster 5MV650 
(SQT-10.6w) 


7.5YR8/2 overlaying 
7.5YR5/4 


Positive 


Kiva D Light Brown Plaster 5MV650 
(SQT-10.7r) 


7.5RY6/4 


Positive 


Kiva D Light Brown Plaster 5MV650 
(SQT-10.8r) 


7.5RY6/4 


Positive 


Kiva D Light Brown Plaster 5MV650 
(SQT-10.9r) 


7.5RY6/4 


Positive 



39 







Figure 7. Photomicrographs of gypsum crystals at 40x magnification that confirm a 
positive chemical reaction for calcium. 



5.4.2 Test for carbonates 

To test for calcium carbonate and other acid soluble contents, this procedure uses 

hydrochloric acid and barium hydroxide. Hydrochloric acid (HC1) in contact with 

carbonate ions (C0 3 2 ~) release carbon dioxide (C0 2 ) gas as shown in the chemical 

formula C032-(s)+ 2HCl(aq) ■* C02(g) + H20 (1) + 2Cl-(aq). Barium hydroxide is 

used to confirm this reaction (see tables 17 and 18). 

TABLE 17 
Test to Confirm the Presence or Absence of Carbonates in Sample SQT-10 (r) 



Sample Name 


Munsell Color 


Test Result 


Confirmation 


Kiva D Light Brown Plaster 
5MV650(SQT-10.1r) 


7.5YR5/4 


Positive 


Positive 


Kiva D Light Brown Plaster 
5MV650(SQT-10.2r) 


7.5YR5/4 


Positive 


Positive 


Kiva D Light Brown Plaster 
5MV650(SQT-10.3r) 


7.5YR5/4 


Positive 


Positive 


Kiva D Light Brown Plaster 
5MV650(SQT-10.4r) 


7.5YR5/4 


Positive 


Positive 


Kiva D Light Brown Plaster 
5MV650(SQT-10.5r) 


7.5YR5/4 


Positive 


Positive 


Kiva D Light Brown Plaster 
5MV650(SQT-10.6r) 


7.5YR5/4 


Positive 


Positive 



40 



TABLE 18 
Chemical Spot Test to Determine the Presence or Absence of Carbonates 



Sample Name 


Munsell Color 


Test Result 


Confirmation 


White Soil (SY- 1.1) 


10YR8/2 


Positive 


Positive 


White Soil (SY- 1.2) 


10YR8/2 


Positive 


Positive 


White Soil (SY- 1.3) 


10YR8/2 


Positive 


Positive 


Reddish Brown Soil (SY-3.1) 


5YR5/4 


Positive 


Positive 


Reddish Brown Soil (SY-3.2) 


5YR5/4 


Positive 


Positive 


Reddish Brown Soil (SY-3.3) 


5YR5/4 


Positive 


Positive 


Kiva D White Plaster 
5MV650(SQT-10.1w) 


7.5YR8/2 overlaying 
7.5YR5/4 


Positive 


Positive 


Kiva D White Plaster 
5MV650(SQT-10.2w) 


7.5YR8/2 overlaying 
7.5YR5/4 


Positive 


Positive 


Kiva D White Plaster 
5MV650(SQT-10.3w) 


7.5YR8/2 overlaying 
7.5YR5/4 


Positive 


Positive 


Kiva D Light Brown Plaster 
5MV650(SQT-10.1r) 


7.5YR5/4 


Positive 


Positive 


Kiva D Light Brown Plaster 
5MV650(SQT-10.2r) 


7.5YR5/4 


Negative 


NA 


Kiva D Light Brown Plaster 
5MV650(SQT-10.3r) 


7.5YR5/4 


Negative 


NA 


Room 24 Light Brown Plaster 
5MV640(STH-2.1r) 


7.5YR6/4 


Negative 


NA 


Room 24 Light Brown Plaster 
5MV640 (STH-2.2r) 


7.5YR6/4 


Negative 


NA 


Room 24 Light Brown Plaster 
5MV640 (STH-2.3r) 


7.5YR6/4 


Negative 


NA 



41 



Chapter 6 
PREPARATION OF SAMPLES WITH UNIFORM THICKNESS 

An initial survey of laboratory testing methods was conducted at the outset of this 
research. Many materials performance-testing standards are intended as a basis for 
comparing commercially manufactured products. This survey identified testing methods 
established by governmental standards for assessing the performance of architectural 
materials in the United States and in Great Britain, relative tests to assess materials 
compatibility developed by the coatings industry, tests to assess soil morphology 
developed by the US Department of Agriculture, testing used in the fields of food science 
and biochemistry, analysis methods used in the field of fine arts conservation, and testing 
methods developed specifically for architectural conservation assessment. American 
Standard Testing Methods (ASTM), a private distributor of standardized testing methods 
proved to be the most useful source of materials testing methods. This decision is 
primarily attributed to the general acceptance of ASTM distributed testing methods and 
accessibility to ASTM publications at the University of Pennsylvania Engineering 
Library. 

When testing surface finishes, it is important that surface finishes are applied at a 
uniform thickness. The cohesive strength, rigidity and expansion/contraction coefficient 
of surface finishes is related to the thickness of the surface coating. This is true of both 
the surface finishes and the adhesive film applied to reattach it. Previous conservation 
studies have determined that both film thickness and the uniformity of its application 

affect its performance. It is well documented that cracking and the eventual deterioration 

42 



of painted finishes are likely to occur in areas with less cohesive strength. 32 Minute flaws 
in the thickness of application can induce cracking in the thinner areas. This is why the 
coatings industry uses leveling agents in their products. Even brush marks produced 
during paint application produce thin areas of finish that are more prone to cracking. 

Determination of finish thickness was established through documentary research. 
Facsimile surface finishes were composed of a 0.8 mm. thick application of wash 
overlaying a 5 mm. thick plaster application and a 25 mm. thick substrate. The 
consistency of finish formulations used for this study required manual leveling and were 
not conducive to brush, spray or even wire-rod applications. This consistency is due to 
particle size distribution of the materials used to formulate reproduction finishes. The 
only control for viscosity and leveling with these plaster and wash formulations was the 
amount of water used and the amount of soil particles in suspension at the time of 
application. Additional problems were encountered while cutting masonry substrates to 
this degree of precision. Attempts were made to apply plaster and wash formulations 
according to both ASTM Practice D823-95(2001) Standard Practices for Producing Films 
of Uniform Thickness of Paint, Varnish, and Related Products on Test Panels and ASTM 
Test Method D4062-99 Standard Test Method for Leveling of Paints by Draw-Down 
Method. 

After some experimentation, ASTM Test Method D823-95 Practice E did prove 
successful. Most commercial draw-down tools are designed to apply at thin layer of 
finish to a larger substrate than was practical for this experiment. They are designed with 



32 Hess. Manfred. "Paint Film Defects: Their Causes and Cure", Reinhold Publishing Corporation, New 
York, 1951. & Berger, Gustav A. and William H. Russell. "Conservation of Paintings: Research and 
Innovations", Archetype Publications: London, 2000. 

43 



guides that slide across the top of the substrate and lift the blade a uniform thickness 
above it. This blade pushes any excess paint down the length of a substrate, thus 
distributing a uniform layer of finish (see figures 9, 10 and 1 1). For the purposes of this 
experiment, more than 70 samples were needed and their small dimensions would not 
accommodate the common commercial blade design. After careful review of current 
products, a modified prototype was constructed, inspired by the Gardco Adjustable 
Micrometer "Microm" Film Applicator and the more simplistic Universal Blade 
Applicator. The prototype illustrated in figure 8 proved successful for the purposes of 
this experiment. 




Universal Blade App licat or 
PaulM .Gardner Pat. 486920 




Gardco Adjustible Micrometer 
"Microm" Film ADDlicator 





Profile of draw down tool prototype 



Side profile of prototype 



Figure 8. Gardner Company Inc. and author's prototype Draw Down Bar Applicators 



33 Paul M. Gardner Company Inc., "Testing Instruments 65 Years Anniversary Catalog", 1996-2002. 

http://www.gardco.com/ 

44 




Figure 9. Tools used to apply Figure 10. Reproduction earthen surface 

reproduction earthen surface finishes finishes before weathering and treatments 




Figure 11. Author applying reproduction earthen surface finishes 

45 



6.1 Substrate Porosity 

Four types of brick substrate were tested to determine their porosity. The same tests 
were run on fragments of unmodified sandstone obtained from the midden of site 
5MV650 in Mesa Verde National Park. Assessment of substrate porosity was conducted 
in accordance with Experiment #8: Water Absorption by Total Immersion and 
Experiment 13: Porosity in Solids: Hypostatic Weighing as specified in the ICCROM 
published ARC: A Laboratory Manual for Architectural Conservators. 34 Three samples 
of sandstone obtained in the vicinity of 5MV650 were tested for porosity. Three samples 
each of four additional substrates were also tested for their comparable porosity. Please 
see attachment A for detailed data on substrate porosity. 

Based on the level of stone decay observed at site 5MV650, it was assumed that the 
porosity of exposed building stone would be high. However, the stone that was tested 
was not exceptionally porous. This may be partially attributed to the method of sample 
preparation for this test. In order to obtain consistent data for comparison to manmade 
materials, all samples were prepared in the same manner. Each sample was cut to exact 
specifications on a diamond bit rotary saw. This method of preparation removed the 
majority of weathered surface from the exterior of each facsimile masonry unit producing 
a smooth and uniform surface. The low porosity of recently modified sandstone and dry 
climate contributes to the durability of this ancestral architecture. 



j4 Teutonico, Jean Marie. "ARC: A Laboratory Manual for Architectural Conservators", ICCROM, 1988, 

p. 35-40 and 52-55. 

46 



The porosity of sandstone fluctuates due to environmental exposure, pore shape and 
pore configuration. This variability can substantially affect the rate of deterioration of 
both the stone substrate and surface finishes applied to it. At the conclusion of this test, 
the facsimile substrate most closely resembling the pore volume of Mesa Verde 
Sandstone was selected as a substrate for further testing (see table 19). Thus, the modern 
brick was selected as a substrate for subsequent surface finish reproduction, accelerated 
weathering, and treatment. 



TABLE 19 
Porosity of substrate samples determined by Hydrostatic Weighing 



Sitetrate Porosity by rtyfrostatic WBpJing 




%Rjcsity 



MasaVende Modem Historic Brick historic Brick Modem Brick 
Sardstcne Bctruded Brick (Yellow) (Fted) 

(P) 



47 



6.2 Relative Shrinkage of Reproduction Surface Finishes 

A simple test was devised to observe the relative contraction of different 
reproduction plaster mixtures. This test was based on modern tests to determine the 
linear shrinkage for soils. Modern extruded bricks were cut to form a coupon with a 
surface measuring 100 mm. by 100 mm. Three mixtures were applied at a thickness of 
approximately 5 mm. in accordance with ASTM Test Method D4062-99 Standard Test 
Method for Leveling of Paints by Draw-Down Method. 

Reproduction Plaster Sample Mixtures: 

• Reddish Brown Plaster = 60:40 sand to silt/clay ratio of SY-3 soil 

• Reddish Brown Wash = 1 0:90 sand to silt/clay ratio of SY-3 soil 

• White Sandstone Wash = 10:90 sand to silt ratio/clay of MR-1 soil 

Each coated brick was placed in a desiccator for 120 hours with an atmospheric 
temperature of 20 degrees Celsius and 30% relative humidity. As further proof of the 
correlation between particle size, shrinkage and adhesion, the sample of reddish brown 
plaster remained fully adhered to its substrate while the white wash and reddish brown 
wash mixtures each pulled up from their substrate at the edges. Since this detachment 
made it difficult to measure shrinkage, both washes were re-set to their substrate by 
wetting with water by capillary action. Then, both were covered with a sheet of fibrous 
Japanese tissue paper tucked under the edges of each brick to prevent the wash from 
pulling up from its substrate as it dries. The washes were dried once again before 

48 



measurements were made to determine relative shrinkage (see figure 12 and table 20). 
For more data on this experiment refer to Appendix F. 




Figure 12. Dried Reproduction Surface Finish Samples 



TABLE 20 
Results of Test to Determine the Relative Shrinkage of Reproduction Finishes 



Sample 


Area (Dry) 


% 
Shrinkage 


Visual Observations 


Reddish Brown 
Plaster 


50000 mm. 


Nominal 


No cracks and no visible shrinkage 


White Sandstone 
Wash 


20958 mm. 


58% 


3 large cracks at concentrated at one 
corner 


Reddish Brown 
Wash 


39680 mm. 


21% 


1 large central crack and 14 smaller 
cracks 



6.3 Relative Water Absorption of Reproduction Surface Finishes 

Based on particle size analysis and previous documentation, three plaster mixtures 
were selected for subsequent testing. All plasters consisted of a 60:40 sand to silt ratio 
and all washes were made up of a 10:90 sand to silt ratio based on particle size. The 

49 



To reproduce the aesthetic effects observed in the field, different Mesa Verde soils were 
used to produce different colored washes. 

Five reproduced plaster samples were used in this experiment to test the water 
absorption of similar finishes in situ (see figure 13). This procedure is described in 
Experiment #9: Water Drop Absorption as specified Teutonico (1988). 35 Additional 
measurements were made immediately after each drop of water was absorbed into the 
sample. The diameter of the water stain made by each drop was immediately measured 
as a relative indication of surface tension and spreadability of the solution. Temperature 
at the time of experiment was 70 degrees Fahrenheit and the Relative Humidity was 34- 
35%. 




Reddish Brown Plaster 



Whitewash Reddish Brown Plaster Reddish Brown Reddish Brown Plaster 
with Whitewash Wash & Reddish Brown Wash 



Figure 13. Surface Finish Samples used to Test Relative Absorption 



Teutonico, Jean Marie. "ARC: A Laboratory Manual for Architectural Conservators", ICCROM 1988 

p. 41-42. 

50 



Reproduction Plaster Sample Mixtures- 

• Reddish Brown Plaster = 60:40 sand to silt ratio of SY-3 soil 

• Reddish Brown Wash = 1 0:90 sand to silt ratio of SY-3 soil 

• White Sandstone Wash = 10:90 sand to silt ratio of MR-1 soil 

• White Wash = 10:90 sand to silt ratio of MR-1 sand and SY-1 silt 

The above tables record the absorption time in tenths of seconds for unweathered 
samples (UW) and for samples that have been subjected to accelerated weathering (W). 
Further measurements were taken to determine the difference between weathered and 
unweathered samples treated with different adhesives. Despite the rapid absorption rate 
of these samples, it can be concluded that weathered surface finishes are more absorptive 
than unweathered surface finishes. The white caliche washes that were treated and 
exposed to the same environmental conditions showed less fluctuation in absorption rate 
regardless of whether they were treated or not. The data generated by this experiment 
suggests that particle size distribution of the earthen finish layers may affect the ability of 
an adhesive to thoroughly wet the particles. Wettability of an adhesive affects both bond 
strength performance and reflectance. Consequently, an understanding of relative water 
absorption is influential when selecting an adhesive formulation to treat environmentally 
weathered earthen surface finishes. 



51 



Chapter 7 
ACCELLERATED WEATHERING - PRELIMINARY TESTING 

This experiment was inspired by ASTM D4 14 1-01 Standard Practice for 
Conducting Black Box and Solar Concentrating Exposures of Coatings. The experiment 
was structured to simulate the environmental factors affecting surface finish 
deterioration, yet these factors were simulated at a higher rate of fluctuation than is 
present in situ. Samples were subjected to controlled fluctuations of heat and moisture 
and monitored for evidence of adhesion loss between the substrate and finish layers. 

7.1 First Cvele 

The first cycle attempted to reproduce blistering by drying a wet sample in the 
oven. This sample was applied to an extruded brick substrate with a porosity of 8.53% 
measured gravimetrically and 17.4% measured hygrostatically. The result was map 
cracking or hairline fractures. 

7.2 Second Cycle 

The second cycle attempted to reproduce blistering by putting a wet sample in the 
oven within a dish of water to reproduce constant heat from the sides and top but rising 
damp from the bottom. This sample was applied to the Modern Brick substrate. The 
result was cracking through to substrate. 

7.3 Third Cycle 

For the third cycle, four samples with different substrates were placed in a pan of 

water with a heat lamp on them and with repeated misting (approximately 6) for a two 

week period. Sample X was also cycled with this group of samples. Two weeks into the 

52 



experiment, each sample was tilted at a 45° angle while wet to see if such samples would 
be cohesive enough to subject subsequent samples to artificial weathering with a Q-U-V 
Accelerated Weathering Tester distributed by Q-Panel Company. This action made it 
apparent that surface finishes applied to the Historic Brick (Red) sample had fully 
detached from their substrate because both layers of surface finishes slid off the substrate 
in one clean action. At this point, the Mesa Verde Sandstone, Modern Extruded Brick (P) 
and Modern Brick samples were propped at a 45° angle and allowed to dry under heat 
lamps. Figure 14 shows the resulting cracks that extended through to the substrate. 




Msa Verde Sandstone HstcricBi±(Ydlcw) Hstoric Bide (Red) MxtmQick Mxfcm Extruded Bick(P) 



Figure 14. Samples used for preliminary testing of the accelerated weathering 

Production of these cracks terminated the experiment for these samples until the 
Mesa Verde Sandstone was once again subjected to cyclic freezing, misting and heat 
lamps to see what the effect of moisture and wide temperature fluctuations would have on 
this sample. The result was interplanar cracking and blistering in close proximity to 



53 



already extant cracks (see table 21). Furthermore, the only examples of large scale 
blistering were observed for surface finish facsimiles prepared on Mesa Verde Sandstone 
substrates. 

TABLE 21 
Observations for Preliminary Accelerated Weathering Test 



Sample 


Observations 


Mesa Verde Sandstone 


Moderate blistering and cracking to substrate when tilted at 
a 45° angle. 


Modern Extruded Brick 
(P) 


Minimal blistering and cracking to substrate when tilted at a 
45° angle. 


Modern Brick 


Moderate blistering and cracking to substrate when tilted at 
a 45° angle. 


Historic Brick (Red) 


Moderate blistering and loss of substrate when tilted at a 45° 
angle. 


Sample X 


Large, single blister formed in the center of this sample 
between the substrate and the surface finishes. 



Loss of adhesion between the substrate and surface finishes occurred differently 
for different types of substrates. For example, the historic brick sample exhibited a 
uniform loss of adhesion at the interface between substrate and finish. This is probably 
due to the high porosity of this substrate. The water quickly penetrated through the 
substrate but was unable to penetrate the less porous surface finishes at the same 
transmission rate. This differential rate of water transmission caused the water to 
congregate in a thin film between the substrate and surface finishes. This film was tick 
enough to actually detach and suspend the finish layers above the substrate, enabling the 
finish layers to slide off the substrate in a single motion when the sample was tipped at a 
45 degree angle. Due to the low porosity of both modern brick samples, each displayed 
swelling and cracking of their surface finishes but neither sample exhibited an noticeable 

54 



loss of adhesion between substrate and surface finish. The two samples of Mesa Verde 
sandstone exhibited shrinking, swelling and blistering of their surface finishes. Sample X 
exhibited immediate and extensive blistering while the other sandstone substrate 
exhibited the smaller, salt covered blisters shown previously in figure 5. The presence 
of salts and the abundance of surface finish layers applied to sample X may account for 
the immediate and extensive blistering observed on this sample. Appendix J provides a 
photographic comparison of all samples tested in this experiment. The large central 
blister on Sample X has been broken in this photograph to show the extent of adhesion 
loss at the conclusion of this experiment. 



55 



Chapter 8 
ACCELERATED WEATHERING OF REPRODUCTION SURFACE FINISHES 

Fifty-six samples of reproduction surface finishes were created for this test. A 
brick with a gravimetric porosity of 7.5% and a hydrostatic porosity of 16.2 was applied 
with a 60:40 fine sand to silt and clay mixture of plaster and allowed to dry before 
applying a 10:90 mixture of wash on top of it. After all samples had cured for at least 
one week, they were subjected to accelerated weathering. Fifty-four samples were 
artificially weathered for a period of five weeks. At the end of each seven-day weathering 
cycle, the samples were fully dried and their conditions were mapped. Samples were 
cycled for a total of 12 hours a day for five cycles of seven days each. At the end of each 
seven-day cycle, the samples were allowed 48 hours of open-air exposure to fully dry 
before the condition of each sample was recorded according to ASTM D7 14-87 Standard 
Practice for Evaluating the Degree of Blistering of Paints, El 808-96 Standard Guide for 
Designing and Conducting Visual Experiments, D660-93(2000) Standard Test Method 
for Evaluating Degree of Checking of Exterior Paints and D66 1-93(2000) Standard Test 
Method for Evaluating Degree of Cracking of Exterior Paints. Each successive seven- 
day cycle was characterized by an incremental increase in the intensity of temperature 
and relative humidity fluctuations to which the samples were exposed. For each of the 
weathering cycles noted below, attempts were made to maintain room temperature at 24° 
Celsius with an RH of 25%. However, fluctuation in the ambient room temperature 

varied as much as 18° due to problems with the school heating system. The freezer was 

56 



set at -10° Celsius with an RH of 100%, and the oven was set at 40° Celsius with an RH 
of 20%. 

8.1 First Cvcle 

Samples were cycled for a seven-day period. For the entire 11 -hour period, 
samples were placed under heat lamps and monitored for changes in temperature and 
relative humidity. At the start of this cycle, samples were placed in a shallow water bath 
and allowed to absorb water through capillary action for 1 V 2 hours. Three hours into the 
cycle, the tops of the samples were misted with water. Six hours into the cycle, the 
samples were misted and placed in the 1 '/2-hour shallow bath once again. Nine hours into 
the cycle, the tops of all samples were misted again. 1 1 hours into the cycle, the heat 
lamps were turned off and samples were allowed to air dry until the beginning of the next 
cycle, 12 hours later. 

Preliminary Observations: 

Minute interfacial blister formation on the caliche samples while wet. This effect 
is less visible once the samples have dried. This effect may not be the result of true 
blistering that is typically caused by isolated interfacial adhesive loss, but may be 
attributed to salt crystallization. Many samples have detached from their substrate. 

8.2 Second Cvcle 

Samples were cycled for a seven-day period. At the start of this cycle, frozen 
samples were placed under heat lamps and monitored for changes in temperature and 
relative humidity. Four hours later, tops of all samples were misted with water and then 
placed in the freezer for four hours. Upon removal from the freezer, samples were placed 

in a shallow water bath and placed under the heat lamps. Twelve hours after the start of 

57 



this cycle, the samples were once again placed into the freezer and allowed to remain 
frozen for 12 hours until the start of the next cycle. 

Preliminary Observations- 

Minor cracking of brownish red samples. No substantial change in the condition 
of caliche samples since the last monitoring. All samples have detached from their 
substrate. 

8.3 Third Cxcle 

Samples were cycled for a seven-day period. At the start of this cycle, frozen 
samples were placed under heat lamps and covered with plastic containers to retain 
humidity as they warmed. Three hours later, the samples were placed in the freezer. 
Samples were removed from the freezer three hours later and placed under the heat 
lamps. Eight hours into this cycle, the samples were covered again to raise the relative 
humidity. Twelve hours into the cycle, samples were again placed into the freezer and 
remained frozen for 12 hours until the start of the next cycle. 

Preliminary Observations : 

Condensation induced minor water damage on a few samples when water drops 
fell onto them. Current conditions accelerating at a slow rate. As an aside, the sandstone 
sample used in the initial testing phase was further subjected to cycle 3 weathering. This 
sample was not detached from its substrate. Nor was it suffering large-scale interfacial 
detachment. Before the outset of cycle 3 weathering, this sample exhibited major 
cracking that was induced by rapidly drying out the sample. Cycle 3 accelerated 
weathering of this sandstone sample resulted in significant blistering concentrated around 

the major cracks in the finishes. By observing the rapid change in condition exhibited by 

58 



this sample as compared to the lack of change in the rest of the samples, it was 
determined that inducing rapid drying would accelerate the deterioration of all samples. 
8.4 Fourth CvHp 

Samples were cycled for a seven-day period. At the start of this cycle, frozen 
samples were placed in an oven for three hours. The top of each sample was misted with 
water and placed in to the freezer. Three hours later, the samples are returned to the 
oven. After three hours in the oven, samples are misted once again and placed in the 
freezer until the beginning of the next cycle. 
Preliminary Observations: 

Rapid drying and major temperature fluctuations induced by oven drying resulted 
in major cracking of the reddish brown samples. Yet the caliche samples remain 
unchanged excepting a few samples where the edges of the caliche layer curled up due to 
contact with the oven wall. Now that cracking had been induced, the samples were once 
again weathered according to the specifications of the third cycle. 
8.5 Fifth Cycle 

Samples were cycled for a seven-day period in accordance with the procedure set 
forth for cycle 3. 

Preliminary Observations: 

Major cracking and interfacial delamination has occurred for the reddish brown 
samples. Yet, the caliche samples did not exhibit major cracking. Desiccation of the 
earthen finish did however make them quite fragile and the precipitation of salts was 
evident on the surface of finishes when dry. 



59 




Figure 15. Accelerated weathering affects on facsimile reddish brown soil and white 
calcium carbonate finish 

Cracked finishes occur as a result of moisture induced swelling and thermal 
contraction of the finish layer while being restrained by the rigid support beneath it. 36 At 
the conclusion of this experiment, samples were visually examined and their conditions 
recorded. There was a notable difference between the deterioration of reddish brown 
samples and that of white caliche samples. Reddish brown samples exhibited more 
expansion/contraction cracking and more interfacial delamination when exposed to the 
same temperature and relative humidity fluctuations than their caliche counterparts. This 
is attributed to the greater reactivity of clays when hydrated. It is also due to the high 
percentage of Calcium Carbonate in the white samples. Ground caliche particles consist 
of a nearly 70% calcium carbonate. Calcium carbonate forms crystals when hydrated. 
Thus, even caliche that has been ground fine enough to qualify within the silt and clay 
range of particle size is more rigid than the clay bound finishes. 



Karpowicz, Adam. "A Study on the Development of Cracks on Paintings", Journal of the American 
Institute for Conservation, Volume 29, Number 2, Article 5, 1990, p. 169-180. 

60 



Clays, such the kaolinite found at Mesa Verde, are activated with water because 
the water coats each clay particle with a thin film of water that is electromagnetically 
held to the surface of the clay particle. This thin film of water acts as a lubricant 
between the particles of clay, allowing the finish layer to expand. In this hydrated state, 
the clays are more flexible than when they are dry. The amount and rate of expansion 
depends on the amount of clay particles within the finish formulation. When the finish 
layer is dried rapidly, the particles do not have time to return to their original position 
before this thin film of water evaporates. 

With the reddish brown samples, differential expansion and contraction of the 
plaster and wash layers produced consistent failure. The greater shrinkage of the wash 
layer in comparison to its underlying plaster layer and the stronger adhesion between the 
two finish layers as compared to adhesion between the finishes and their substrate caused 
the finishes to lift up off the substrate. A build up of stress induced by this differential 
shrinkage concentrates strain at the center of the surface finish. Cracking at the center of 
the sample releases this build up of internal stress within finish layers (see figure 16). 
However, it also causes a weakness in the cohesion of the layer and allows water to 
penetrate the crack. Freezing of water within such cracks causes further stress due to the 
expansion of the frozen water placing pressure onto the surface finishes. Thus, a cracked 
surface finish deteriorates faster than one that exhibits no cracking. 



61 




Arrows indicate forces inposed by differential contraction of finish layers. 



Photograph of weathered facsimile. 



Figure 16. Delamination and detachment of facsimile earthen surface finishes 

In contrast to the wash formulated with reddish brown soil, two different types of 
white binder were formulated. Both binders were made by grinding stone to a particle 
size that was small enough to pass through a 75um screen. Each was then mixed with the 
appropriate portion of sand sized particles and applied to the same substrate as the 
reddish brown samples. Even before subjecting these samples to accelerated weathering, 
it was apparent that the white sandstone binder shrank much more than the caliche 
binder. In fact, five of the twelve samples made from white sandstone cracked while 
drying after the wash was applied. The process of grinding white sandstone small 
enough to pass through a 75pm screen is not an exacting method and probably ground the 
particles smaller than was needed to clear the screen. Theoretically, the smaller the 
particles, the more that a finish layer will shrink as it dries. However, the caliche samples 
were made according to this same method and since none of the 28 caliche samples 
exhibited this extent of cracking even after weathering. 



62 



The cohesive strength of both wash formulations are dependant upon the amount 
of surface area that particles within the finish are in contact with each other. When wet, 
the surface area of each particle is in complete contact with the water making the water 
act as a binder in the clay formulation while it is wet. When dry, both the caliche and 
clay particles are small enough that they fill the voids between the sand particles. The 
application of finishes by smoothing them onto their substrate both compresses and aligns 
the particles parallel to the surface of their substrate. This interlocking of particles 
accounts for the cohesive strength within a finish layer and make finishes with a high 
clay content less porous than those formulated with a high sand content. Washes with 
high clay content characteristically swell more when hydrated and are more cohesive 
when applied in thin layers. 



63 



Chapter 9 

BINDING AGENTS COMMONLY USED IN 

ADHESIVE, SEALANT, AND PAINT FORMULATIONS 

The following text lists some of the traditional binders used in modern paintings. 
This brief overview of paint binders does not go into detail regarding specific types of 
materials used to formulate alkyd or proteinacious binders. Since the subject of this 
paper is to compare the material properties of two formulations of acrylic and two 
formulations of protein based adhesives, the following description only provides an 
overview of potential alternatives. 

9.1 Mineral Binders 

For the purposes of this paper, binders formed by crystalline formation and particle 
size distributions that produce a strong enough intermolecular attraction to produce a 
stable film will be classified as mineral binders. Finishes in which the pigment or filler 
particles are bound by crystal formation include mortars, cements, frescos, calcium based 
plasters and some stuccos. These are reaction adhesives that form strong secondary 
bonds that exhibit minimal shrinkage and a rigid structure. 37 Using the example of 
fresco painting, pigment is bound in place by a chemical reaction that occurs when the 
applied suspension of wet calcium hydroxide and fine sand reacts with the air to form a 
crystalline calcium carbonate matrix that secures the pigment particles into place. During 
this process, quicklime that is formed by heating calcium carbonate, and then hydrated to 



37 Wilks, Helen et al. Science for Conservators: Adhesives and Coatings, Volume 3, Conservation Unit of 
the Museums & Galleries Commission and Routledge, 1992. 

64 



form lime, binds the fresco pigments with the crystal structures that form as the lime 
cures and reacts with the air. Aluminum and potassium silicates are added to plaster to 
form cements 

Due to their structure, calcium carbonate particles expand and contract with water 
less than comparably sized clay particles. This property and the white color of calcium 
carbonate make derivatives such as chalk, whiting, lime, caliche and gypsum are ideal for 
use as fillers and pigments for paint and plaster formulations. Mesa Verde soils that were 
tested potentially contain as much as 70% calcium carbonate. It is probable that these 
caliche, high lime content soils were used for making the plasters and mortars at Mesa 
Verde National Park. 

9.2 Plant Binders 

Plant resins, gums and vegetable oils have been historically used in the formulation 
of paint binders as well. Organic varnishes, watercolors and oil paints are examples of 
plant binding mediums. The most common oil paint uses linseed oil obtained by 
processing flaxseeds. Film formation of linseed-oil-based paints occurs by the cross- 
linking of carbon-carbon double bonds that occurs as the film oxidizes. 39 Many plant 
binders are cellulose based. 40 Cellulose is a long chain polymer that occurs naturally in 



38 Jusko, Don A. "History of Painting Mediums... Glue, Wax Paint, Cera Colla, Mastic, Casein Paint, 
Fresco, Egg, Oil Paint, Acrylic Paint", mauigateway.com. 
http://www.mauigateway.com/~donjusko/ 1 mediums.htm# 1 00,000 B/C 

39 Dunn, Kevin M. "Paint", Course readings for CHEM710: Chemistry and Art, Hampden-Sydney College 
Department of Chemistry, 1996. http://cator.hsc.edu/~mollusk/ChemArt/paint/paints.html 

40 Wilks, Helen et al. Science for Conservators: Adhesives and Coatings, Volume 3, Conservation Unit of 
the Museums & Galleries Commission and Routledge, 1992. 

65 



plants. 41 Many plant-based binders were available to ancestral Puebloan painters. 42 For 
example, the pinion tree extruded a sticky sap that is still used today as a traditional 
sealant for ceramic vessels. 43 Boiling of the seeds also produces pine nut oil. Tree resins 
are the source of many alcohol and turpentine based binding systems whose use has been 
dated as early as 1600BC. Archeologists have also found numerous vessels that have 
been repaired with an adhesive made from pinion pitch. (Figure 1.) Some modern 
Puebloan people still use pine pitch as a sealant for ceramic vessels used in traditional 
ceremonies. 45 Pine pitch is concentrated tree sap. Processing the sap of trees forms 
resins, distilled turpentine solvents, and fermented alcohols to dilute them. 46 Gum 
Arabic, a commercially processed tree sap, is combined with glycerin in the formulation 
of watercolor paint. It is also used in the formulation of gouache by combining gum 
arabic with powdered gypsum (CaSO.*). 



41 Wilks, Helen et al. Science for Conservators: Adhesives and Coatings, Volume 3, Conservation Unit of 
the Museums & Galleries Commission and Routledge, 1992. 

42 Beas, Maria Isabel G. "Traditional Architectural Renders on Earthen Surfaces", University of 
Pennsylvania Masters Thesis, 1991 

43 Personal communication with archeolgists and with staff from the CU Cultural Center in Cortez, CO, 
10/15/2001. 

44 Jusko, Don A. "History of Painting Mediums... Glue, Wax Paint, Cera Colla, Mastic, Casein Paint, 
Fresco, Egg, Oil Paint, Acrylic Paint", mauigateway.com. 
http://www.mauigateway.com/~donjusko/ 1 mediums. htm# 1 00,000 B/C 

45 Artifact Database for the Chappell Collection of ceramic vessels stored at the Anasazi Heritage Center. 

46 Jusko, Don A. "History of Painting Mediums... Glue, Wax Paint, Cera Colla, Mastic, Casein Paint, 
Fresco, Egg, Oil Paint, Acrylic Paint", mauigateway.com. 
http-//www.mauigateway.com/~donjusko/lmediums.htm# 100,000 B/C 

66 




> 



Figure 17. Ancestral Puebloan sherd mended with pinion pitch. 
Found by Archeologist Joel Brisben in Room 16(1) of site 5MV640, July 2002 

9.3 Wax Binders 

Common waxes used as paint binders and adhesives include beeswax, paraffin wax 
and more recently, microcrystine wax. Both beeswax and petroleum based waxes are 
thermoset polymers that primarily consist of hydrocarbons. Beeswax was commonly used 
as a binder in ancient Egypt, Greece and Rome into the 8 th century AD. 47 Waxes are still 
used by modern day painters and some traditional fresco painters to enhance their 
artworks with overpainted detailing. 4 

9.4 Alkyd Binders 

Alkyds are manmade formulations of polymeric esters that cross-link during film 
formation. This classification doesn't fit neatly into the classification of animal, plant or 



47 http://cator.hsc.edu/~mollusk/ChemArt/paint/paints.html 

48 Personal communication with Richard Raisellis 

67 



mineral since the oils used in alkyd formulations may be derived from any of these three 
initial sources. The value of saturation for an oil determines its chemical properties as it 
approaches its glass transition point. Commercially, alkyd paints are classified by the 
amount of oil contained within the solution. These classifications vary from Type I oil- 
free polyester to Type IV long oil alkyds that contain more oil than is able to react within 
the molecule through esterfication. 49 Many oils used in the production of alkyd paints are 
also used as plasticizer additives within the formulation of paints based on other 
mediums. It is notable that alkyd paints are often recommended for alkaline surfaces due 
to the tendency of the more acidic formulations to saponify. 50 However, the inclusion of 
phenolic resin additives can improve an alkyd paints alkali resistance. 51 

The most common polyol used in the manufacture of alkyd paints is glycerin. 
Glycerin is obtained as a by-product of soap manufacture and may be of either animal or 
vegetable origin. In the early 1940s glycerin was able to be commercially produced from 
petroleum sources. 52 Glycerin has a high boiling point and a lower viscosity than other 
polyols with a functionality higher than three. This polyol is worthy of note for this 
paper since glycerin is currently being used as a plasticizer in the gelatin-based treatment 
adhesive used at Mesa Verde. 

One other polyol sometimes used in the production of Alkyd paints should be noted. 
Sorbitol is commonly used as a plasticizer for gelatin in the food industry. 53 It is 



49 Martins. Alkyd Resins p29 

50 Hess, Paint film defects 

51 Martins. Alkyd Resins p85 

52 Martins. Alkyd Resins p40 

53 SORBITOL 

68 



"produced by the catalytic hydrogenation of glucose." 54 Sorbitol contains six hydroxyl 
groups but is usually referenced as a functionality of four due to the inability of all 
hydroxyl groups to esterify by normal alkyd processing techniques. 

9.5 Acrylic Binders 

Since 1945, manmade acrylic esters have been manufactured as a paint medium. 
Both pigment and monomers of compounds such as methyl acrylate or vinyl acetate are 
suspended within an aqueous solution. 55 Depending on the chemical formulation of the 
acrylic solution, film formation may occur through either solvent loss or by crosslinking 
of these monomers. Acrylics are commonly used as adhesives and sealants for artifact 
and painting consolidation. Reasons for their use include consistencies in commercial 
manufacture, well-established solubility parameters and transparency of the resulting 
film. The most common, modern day, archeological use of acrylic resins is the use of 
Acryloid B-72 (US. Patent) / Paraloid B-72 (UK. Patent) for artifact labeling and 
mending potsherds. The National Park Service has used Rhoplex brand acrylic emulsion 
modified soil mortars to stabilize structures at archeological sites since the early 1970s. 56 
In fact, modified mortar and construction sealant formulations were sought by the 
National Park Service as early as the 1930s. Currently, Rohm and Haas Corporation 
supplies Mesa Verde National Park with Rhoplex E-330 for use in their acrylic emulsion 



54 rtins. Alkyd Resins p43 

55 Dunn, Kevin M. "Paint", Course readings for CHEM710: Chemistry and Art, Hampden-Sydney College 
Department of Chemistry, 1996. http://cator.hsc.edu/~mollusk/ChemArt/paint/paints.html 

56 Hartzler, Robert. "Acrylic-modified earthen mortar: a program of investigation and laboratory research 
into acrylic-modified earthen mortar used at three prehistoric Pueblo sites", Conservation Program, 
Intermountain Cultural Resource Center, Intermountain Field Area, National Park Service, Dept. of the 
Interior, Santa Fe, NM, 1996, p. 18. 

69 



modified soil mortars. 57 Both of the acrylic emulsions selected for this study are 
marketed for the modification of soil mortars by Rohm and Haas Corporation. Numerous 
adhesives such as methyl methacrylates, silicone solutions and polyvinyl acetates have 
also been used as adhesives to stabilize earthen plasters at archeological sites. 

9.6 Animal Binders 

Often credited as the first paint binder used, animal proteins such as milk, egg, blood 
and gelatin are still used today. Proteins are co-polymers made up of amino acids. 5 The 
subgroup Albumin includes "any of numerous simple heat-coagulable water-soluble 
proteins that occur in blood plasma or serum, muscle, eggs, milk, and other animal 
substances and in many plant tissues and fluids." 59 When used as film forming binders, 
this group of proteins is procured through the denaturation of collagen. 60 These proteins 
are usually specified by the generic names given to the paint formulations that they are 
contained within. 

Eggs are used in tempura formulations that were most common in European fine arts 
painting prior to the prominence of oil paints in the 15 th century 61 . The properties of 
tempura film formation is attributed to both denaturation of protein and polymerization of 
fats within the egg yolk. "The proteins form many hydrogen bonds with each other and 



57 Personal communication with Kathy Fiero, Stabilization Archeologist at Mesa Verde, 3/15/2002. 

58 Wilks, Helen et al. Science for Conservators: Adhesives and Coatings, Volume 3, Conservation Unit of 
the Museums & Galleries Commission and Routledge, 1992. 

59 Merriam- Webster Inc. "Dictionary", http://www.webster.com 

60 Wilks, Helen et al. Science for Conservators: Adhesives and Coatings, Volume 3, Conservation Unit of 
the Museums & Galleries Commission and Routledge, 1992. 

61 Jusko, Don A. "History of Painting Mediums... Glue, Wax Paint, Cera Colla, Mastic, Casein Paint, 
Fresco, Egg, Oil Paint, Acrylic Paint", mauigateway.com. 
http://www.mauigateway.eom/~donjusko/lmediums.htm# 100,000 B/C 

70 



with the surface, locking the pigments into a solid matrix. As they age, these proteins 
form covalent bonds with each other, making the matrix very stable." 62 

Milk is the common binder for casein. However, the term casein, or milk paint, has 
also been used to refer to paint formulations based on other protienacious binders. A 
survey of the literature revealed the use of gelatin and raw blood as binders used in the 
manufacture of casein. 

Animal proteins such as gelatin and blood are used in both paint and adhesive 
formulations. For example, one early documented albumen solution formulated with a 
protein binder of egg whites and ox blood with a filler of lime was used as a construction 
sealant 63 . 



62 Dunn, Kevin M. "Paint", Course readings for CHEM710: Chemistry and Art, Hampden-Sydney College 
Department of Chemistry, 1996. http://cator.hsc.edu/~mollusk/ChemArt/paint/paints.html 

63 Thornton, Jonathan. "A Brief History and Review of the Early Practice and Materials of Gap-Filling in 
the West", Journal of American Institute for Conservation 1998, Volume 37, Number 1, Article 2, p. 3-22. 

71 



Chapter 10 
GELATIN BASED ADHESIVES 

Gelatin is an animal binder derived from animal proteins. It a generally defined as a 
more refined version of what artists term hide glue. Hide glue has been traditionally 
combined with calcium carbonate or calcium sulfate and water in formulations for sizing, 
gesso, gauche used in fine arts applications. Furthermore, calcium carbonate in the form 
of chalk or whiting has served as a traditional paint pigment in paint formulations 
utilizing various other mediums as well. Gelatin and calcium carbonate have been 
combined with plant resins to formulate architectural composition reliefs. Gelatin also 
has a longstanding history of use as photographic emulsions. Weak protein solutions are 
also used as biodegradable-facing adhesive when administering conservation treatments 
on calcium carbonate surfaces. 64 

There are many different forms of animal based glue with the forms distinguished by 
which animal parts are used for its manufacture and the way that the glue is 
processed. (Figure 2.) The type of animal, parts of the animal used, and age of the animal 
can all affect physical properties of the final product even when a product is marketed 
under the same name. Common fluctuations in material properties include differences in 
pH and gel strength. Animal glue collagen is obtained from the bone, tendon and skin of 



64 Berger, Gustav A. and William H. Russell. "Conservation of Paintings : Research and Innovations", 
Archetype Publications: London, 2000. 

72 



animals. Other naturally occurring polymers are obtained by processing the keratin that 
is contained within feathers, horns and hair. 65 

TABLE 22 
Types of Commercially Available Gelatin 



Type of Gelatin 


Raw Material 


Physical Properties 


Isnglass 


sturgeon bladders 


Low gel point 


Hide glue 


bovine hide 


High coefficient of expansion 


Bone glue 


bovine bones 


Moderate coefficient of expansion 


Animal glue 


bovine bones, bovine hide, and 
pig skin 


High coefficient of expansion 


Rabbit skin glue 


Rabbit skin 


High molecular weight 


Fish glue 


Fish skin 


Weak gel strength 



Gelatin is an organic, hydrocolloidal compound of proteins that is produced from 
the denaturation of animal collagen. The chemical composition of gelatin-based hide 
glue roughly constitutes 51% carbon, 6% hydrogen, 24% oxygen and 18% nitrogen. 66 
Historically, animal glues have been made by breaking the original polymer chains 
derived from animal hides, tendons and bones. This was done by boiling the animal parts 
at a temperature of 80-90° Celsius 67 to break their naturally occurring polymer chains and 



65 Wilks, Helen et al. Science for Conservators: Adhesives and Coatings, Volume 3, Conservation Unit of 
the Museums & Galleries Commission and Routledge, 1992. 

66 Matt T. Roberts, Don Etherington and Margaret R. Brown. "Bookbinding and the Conservation of books: 
A Dictionary of Descriptive Terminology", Stanford University Libraries, 1994. 
http://palimpsest.stanford.edu/don/don.html 

67 Matt T. Roberts, Don Etherington and Margaret R. Brown. "Bookbinding and the Conservation of books: 
A Dictionary of Descriptive Terminology", Stanford University Libraries, 1994. 

73 



then concentrating the resulting broth 68 by drying it into sheets of solid gelatin. However, 
the denaturation of proteins can be induced through many different methods. Exposure to 
heat, pressure, salts, acids, alkalis, and alcohols can be used for the denaturation of 
collagen. The production of gelatin involves two chemical modifications. The first is to 
induce the denaturation of the proteins while the second is a process of aggregation. 69 

Modern methods for mass-producing gelatin use acid or alkaline digestion of 
animal parts to rapidly break these chains. The resulting gelatin differs in pH and 
viscosity depending on the raw materials used and manufacturing process. The grade of 
the final product is largely dependant upon what type of animal parts are used, the age of 
the animals , the purity of processing through filtering. Demineralization to remove 
salts and the extent to which fats were originally removed also affects the physical 
properties of gelatin. The pH of gelatin is largely determined by its manufacturing 
process. Hide glues generally have a pH within the range of 6.5-7.4. Acidic glues tend 
to absorb less water and set more slowly than glues that are more alkaline. Gelatin 
manufactured by means of an acid bath generally has an isoionic point between 7 and 9 
while alkaline processed gelatin ranges between 4.8 and 5.2. 71 Gelatin has "both positive 
and negative charges on the molecule (and no net charge at the isoionic point)." 72 This 
allows the gelatin to crosslink with acid groups when the gelatin is at a pH that enables 



http://palimpsest.stanford.edu/don/don.html & Cole, Bernard. "Gelatine Food Science", University of 
Pretoria, http://www.gelatin.co.za/gltn 1 .html 

68 Thornton, Jonathan. "A Brief History and Review of the Early Practice and Materials of Gap-Filling in 
the West", Journal of American Institute for Conservation 1998, Volume 37, Number 1, Article 2, p. 3-22. 

69 Gossett, P.W., S.S.H. Rizvi, and R.C. Baker. "Quantitative Analysis of Gelation in Egg Protein 
Systems", Food Technology, Vol. 38, Num. 5, May 1984, p. 67-96. 

70 Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/glml.html 

71 Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/glml.html 

72 Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/glml.html 

74 



the side chains to not carry an electrostatic charge. 73 Thus, pH affects the stability, 
solubility 74 and potential for internal plasticity when combined in an adhesive solution. 
"A gel network with a certain degree of order can be attained if the aggregation step 
occurs more slowly than the denaturation step. Thus giving the denatured protein 
molecule, time to orient themselves before aggregation; this is lower in opacity and 
higher in elasticity then one where aggregation is not suppressed. Schmidt (1981) 
suggested that if aggregation occurs simultaneously with denaturation, an opaque, less 
elastic gel results." 75 

As Matt T. Roberts and Don Etherington state, "Electrostatic Charge is one of the 
most commonly investigated factors. The pH as well as the ionic strength of the protein 
environment can alter the charge distribution among the amino acid side chains and can 
either decrease or increase the protein-protein interaction,. Nakamura et al. (1978) 
concluded that the main factor contributing to the heat-induced aggregation of ovalbumin 
(pi 4.5-4.6) is the degree of electrostatic repulsion among the denatured protein 
molecules. When the heat-denatured protein concentration is high (>0.5%), the aggregate 
size decreases as the pH increases from 5.8 to 10.0; this is due to increased repulsive 
forces among the protein molecules at the alkaline pH levels. Conversely, decreasing the 
pH or adding cations decreases the negative charge and accelerates aggregate formation, 
as does increasing the ionic strength." 

Gelatins are thermoplastic long-chain polymers of collagen that have been broken 
into smaller chains attached with weak secondary bonds to molecules. The protein 



Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/gltnl.htm] 
Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/gltnl.html 



75 



structure of gelatin is a triple helix structure held together by non-covalent molecular 
forces. The triple helix structure is formed from peptide bonded alpha chains of glycine, 
propline and hydroxyproline. 76 The content of amino acids within gelatin also includes 
glutamic acid, alanine, arginine, aspartic acid, lysine, serine, leucine, valine, 
phenylalanine, threonine, isoleucine, hydroxylysine, methionine, histidine and tyrisine 
depending on the method of manufacture. 

Gelatin is an organic polymer that is used in the production of adhesives (wood 
glues, medical adhesives), paints (distempers, canvas sizing, stucco marble), medical 
(surgical adhesive, thin-section microscopy samples, etc.), pharmaceutical drugs (gelatin 
capsules), foods, etc. Gelatin is manufactured to a more pure grade than traditional hide 
glues, but is essentially a variation of the same material. 

Numerous conservation studies have been conducted to assess the material 
properties of gelatin used in the manufacture of photographic emulsions and in the sizing 
and gesso of oil paintings. One question repeatedly addressed in these conservation 
studies include relative humidity induced expansion and contraction. Similar to the 
alignment of clay particles within a finish layer, fibrils within a gelatin solution naturally 
align themselves parallel to their substrate if the dwell time is long enough for them to do 
so. Above their glass transition temperature, gelatin solutions are viscous, amorphously 
structured solutions. This is because at high temperatures, their molecules slide over one 



75 Gossett, P.W., S.S.H. Rizvi, and R.C. Baker. "Quantitative Analysis of Gelation in Egg Protein 
Systems", Food Technology, Volume 38, Number 5, May 1984, p. 67-96. 

76 Friedli, Georges-Louis. "Protiens", Friedli Enterprises. 
http://www.friedli.eom/herbs/phytochem/proteins.html#gelation 

77 Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/gltol.html ( 



76 



another easily making the solution less viscous. The rigidity of a gelatin solution in gel 
state is determined by the spacing between cross-links along the molecule. 

When the gelatin fibrils are aligned parallel to one another, hygroscopic swelling 
occurs primarily along one axis. Therefore, the way that a gelatin film swells in humid 
conditions is an indication of how well the fibrils are aligned to one another. It is 
significant that aligned fibrils are isotropic and misaligned fibrils exhibit birefringence 
when viewed microscopically. Studies conducted by Karpowicz, Simms and Blake have 
confirmed that the misalignment of these fibrils occurs when the film is restrained while 



79 

curing. 



The method of adhesive application that is used at Mesa Verde would 
theoretically restrain the expansion and contraction of these fibrils unless there is 
sufficient time for the solution to cure. Another reason to allow for increased dwell time 
before the solution fully cures is to allow the adhesive solution to fully wet the particles 
of the substrate and finish. 

Previously published tests showed the same results as were exhibited with the 
cohesive shrinkage tests conducted for this study. On previous tests, the gelatin size 
remained intact at the center of the canvas, but cohesive shrinkage was such that the 
gelatin pulled into the center and damage resulted on the edges of the canvas due to this 



78 Cassar, JoAnn and Roberta de Angelis. "Glossary. Materials used in 19th and 20th century Plaster 
Architecture. Plaster Architecture Essay, Culture 2000 Programme of the European Union. 
http://www.plasterarc.net/essay/essay/CassarG.html 

79 Karpowicz, Adam. "A Study on the Development of Cracks on Paintings", Journal of the American 
Institute for Conservation, Volume 29, Number 2, Article 5, 1990, p. 169-180. 

80 Berger, Gustav A. and William H. Russell. "Conservation of Paintings : Research and Innovations", 
Archetype Publications: London, 2000. 

77 



internal contraction. 81 Gelatin experiences a period of relaxation when exposed to a 
constant source of stress. In other words, gelatin that has been subjected to a constant 
level of stress may adjust to that level of stress rather than releasing the stress in the form 
of strain-induced cracks. This has been the topic of research in the storage of 
photographic emulsions and their reaction to fluctuations in relative humidity. 

There are many uses of gelatin, so many additives are used when formulating it 
for those uses (see appendix D) For the purposes of this discussion, I will concentrate on 
additives that change the hardness, flexibility, biodeterioration resistance, viscosity and 
particle wettability. Each of these properties are relevant to the effectiveness and 
durability of in-situ reattachment. The contraction of gelatin solutions while approaching 
their glass transition temperature is so great that gelatin fdms are known to break ceramic 
and glass containers when heated for quick set in the lab. 82 The pharmaceutical, food and 
photographic industries have identified many cross-linking polymers that join with 
gelatin and often serve more than one function. Common additives that change the 
elasticity (E-modulus) of gelatin solutions include polyhydric alcohols like glycerol, 
propylene glycol, sorbitol, and formaldehyde. Cross-linking with acrylic is being studied 
and cross-linking of gelatin with aldehydes such as glutaraldhyde is also being 
researched. Cross-linking of gelatin using the enryme trans-glutaminase is used to join 
gelatin to other proteins. 



81 Karpowicz, Adam. "A Study on the Development of Cracks on Paintings", Journal of the American 
Institute for Conservation, Volume 29, Number 2, Article 5, 1990, p. 169-180. 

82 Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/glml.html 

78 



Chapter 11 
CURRENT ADHESIVE TREATMENT METHODS 

The following treatment description outlines the treatment methods developed by 
the University of Pennsylvania Architectural Conservation Lab. This method addressed 
in this study uses different concentrations of Gelatin in solution applied at different 
temperatures. Since gelatin can be converted to three different states based on its water 
content and temperature, three methods of application were developed for the use of this 
adhesive. 

Adhesive Formulations: 
(percentages of weight to volume) 

1) 5% gelatin plus 10% glycerin in water 

2) 10% gelatin plus 10% glycerin in water 

Prior to all treatments, the area of detachment is fully documented, cleared of all 
loose material and debris that may have collected behind the layer of surface finish, and 
pre-wetted with water or water and isopropyl alcohol. This initial preparation is very 
important to the longevity and adhesive strength of any treatment. Once the adhesive is 
applied, the exterior surface of the detached layer is misted with a solution of 30% 
isopropyl alcohol in water. The alcohol is a wetting agent, which lowers the surface 
tension of the water allowing the water to more readily coat the particles that make up the 
detached layer. Both the glycerin that is used in the formulation of these gelatin solutions 

79 



and the isopropyl alcohol serve as wetting agents in the production of printing fountain 
solutions. 83 

Glycerin is an oil that can be obtained from many substances. Glycerol of the 
chemical formula CH2(OH)CH(OH)CH20H is a trihedic alcohol with a molecular weight 
of 92.09 and a specific gravity of 1.26. It is processed from petroleum products, 
vegetables and animals. Its most common use is in cosmetics and soaps. As a surfactant, 
it lowers the surface tension of water at the interface of water to solid. In the case of 
pigment particles, this allows the particles to be more thoroughly coated with the binder. 
It is termed a surfactant and a wetting agent when used in this fashion. 

Glycerin is commonly combined with fatty acids in a 1:3 ratio on a molecular basis to 
form one molecule of oil for use as a plasticizing additive in paint and adhesive 
formulations. 84 Due to its hygroscopic nature, glycerol absorbs a large quantity of water. 
Thus, both gelatin and its added plasticizing agent, glycerin, are biodegradable and retain 
water in a humid environment. Thus, the susceptibility of this treatment to biological 
growth, specifically mold, is high. One solution to this problem is to add an antiseptic 
biocide to the adhesive formulation. 85 

Misting of the treatment area serves two purposes. First it relaxes the surface tension 
which binds the particles within the detached surface finish together as a rigid mass. The 
water solution penetrates into the pores of the finish and creates a thin layer of water that 



83 Ferguson, Ken, Joel Langdon, and Jack Power. "Van Son Printer's Digest: Printing Reference Guide" 
Van Son Tech Center 3 rd edition. Van Son Holland Ink Corporation of America, Mineola, NY, p.8. 
http://teched.vt.edu/gcc/HTML/VirtualTextbook/PDFs/PrintersDigest.pdf 

84 Gettens, Rutherford J.; Stout, George L. Painting Materials : A Short Encyclopedia 
Dover Publications Inc., Mineola, NY, 1965. 



coats the clay particles within the layer. This thin coating of water is said to activate the 
clay particles. 86 . .The shape of clay particles allows them to slide easily over one another 
making the layer more pliable when pressure is applied. 87 Second, the evaporation rate of 
isopropyl alcohol is faster than that of water. Thus, a solution of isopropyl alcohol mixed 
with water theoretically provides a more rapid and more thorough wetting of the pigment 
particles remaining in the surface finish while also increasing the evaporation rate of this 
water based solution. The result of better wetting is better coverage of the particles by 
the adhesive and thus an increase in adhesion. Rapid drying reduces the possibility of 
overwetting the earthen plaster layers which may deform the stratigraphic sequencing of 
individual layers. 

While resetting the detached finish to its original plane, conservators at the University 
of Pennsylvania experienced good results when using a cosmetic sponge as a buffer while 
applying pressure to the detached layer. This evens out the pressure to cover a greater 
surface area and absorbs any excess solution on the surface of the finish. 

11.1 Cold Gelatin Treatments 

Cold treatment is the term used to describe application of 5% and 10% gelatin 
solutions that have been applied in their gelled state. According to the testing conduced 
for this paper, the gelatin solutions used at Mesa Verde form a firm gel between 20° C. 
(68° F.) and 25° C. (77° F.) depending on the solution formulation. Cold treatment is 



85 Matt T. Roberts, Don Etherington and Margaret R. Brown. "Bookbinding and the Conservation of books: 
A Dictionary of Descriptive Terminology", Stanford University Libraries, 1994. 
http://palimpsest.stanford.edu/don/don.html 

86 Brady.Nyle C. and Ray R.Weil. "The Nature and Properties of Soils", 1 1th Edition, Macmillan 
Publishing, 1996. 

87 Dix, Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from 
Mug House, Mesa Verde National Park Colorado", University of Pennsylvania Masters Thesis, 1996. 



primarily used when the area of detachment is large enough that the adhesive can be 
applied without the use of a hypodermic syringe. In most cases, cold treatments are 
applied between a detached layer and its substrate with a microspatula. After the layer 
has been misted with isopropyl alcohol and allowed to become pliable, a slight pressure 
is applied to the outermost surface of the detached layer to gently set it back into place. 

11.2 Warm Gelatin Treatments 

Warm gelatin treatments are applied with a hypodermic syringe at a temperature 
approximating 36 C. (98° F.). This method of application subjects the adhesive to shear 
stress while it is passed through the needle. The recommended temperature for warm 
gelatin treatments is above the melting point for glycerin and above the glass transition 
temperature for the gelatin. Thus, the mixture is quite viscous and there may be the 
potential for crosslinking of the gelatin and the glycerin used in this adhesive solution. 



82 



Chapter 12 
ANALYSIS OF ADHESIVE PERFORMANCE 

Responsible conservation practice dictates that the conservator understand the 
material properties of the object to be treated, the properties of materials used to treat it 
and a consideration for the effects that a treatment will have on the object. Careful 
assessment of the mechanisms that contribute to the deterioration of the object dictate the 
treatment method that will be used. Detailed documentation of existing conditions prior 
to and after treatment provides for the continued monitoring and assessment of specific 
treatments. This approach has been adopted by the University of Pennsylvania in 
developing grouts and adhesives for conservation use at archeological sites. It is also the 
basis for the testing program set forth in this thesis. 

Initial testing and analysis to determine the materials characteristics of original 
surface finishes were determined by visual examination and documentation of in situ 
plaster finishes during the 2000 and 2001 field season. As a basis for this study, 
Microscopic cross-sectional analysis was provided by University of Pennsylvania theses 
and by research by the Getty Conservation Institute. Petrographic analysis of mortar and 
plaster samples at Mesa Verde was conducted by Mary Griffith 88 , and soils studies were 
conducted by the Department of Agriculture. 89 Previous surveys of Mesa Verde Surface 



88 Nordby, Larry and Mary Griffins. "Cliff Palace Building Materials Classifiaction and Selection", 
December, 1999. 

89 USD A -NRCS Soil Survey Division. "National SSURGO Database Data Access", January 8, 2001. 
http://www.ftw.nrcs.usda.gov/ssur_data.html 

83 



Finishes were conducted by Wood Canyon Archeology 90 and Constance Silver 91 . 
Mechanical testing of the stabilization soils used at Mesa Verde was published by Bob 
Hartzler in 1996. 92 That same year, Linnaea Dix conducted microscopic analysis of 
Mesa Verde surface finishes. 93 This study was followed up with the study conducted by 
Mary Slater in 1999. 94 A third study was conducted by Urs Mueler of the Getty 
Conservation Institute in 200 1. 95 Various treatment methods were laboratory tested in 
the theses of Maria Isabel Beas, 96 Angelyn Bass-Rivera, 97 and Kechia Fong. 98 Park 
specific conditions terminology and in-situ testing of treatment methods were conducted 
by University of Pennsylvania Conservation Laboratory field crews from 1994 to 1997. 
This research the basis for current conservation practices at Mesa Verde. 

The purposes of this study are to assess the properties of materials that are currently 
being used by the University of Pennsylvania to stabilize original earthen surface finishes 
and to assess their interaction with the materials that were used to formulate these 



90 Fetterman, Jerry and Linda Honeycutt, The 1987 Mesa Verde Plaster Recordation Project Project, Woods 
Canyon Archaeological Consultants, Inc., Yellow Jacket, CO, 1987. 

91 Silver, Constance. 

Analysis and Conservation of Pueblo Architectural Finishes in the American Southwest, Adobe 90, 1990. 
1981 Report on the Development of Methods for the Conservation of Pueblo Indian Mural Paintings in the 
American Southwest, National Park Service, 1982. 
The State of Preservation of Pueblo Indian Mural Paintings in the American Southwest, ICCROM, 1980. 

92 Hartzler, Robert. "Acrylic-modified earthen mortar: a program of investigation and laboratory research 
into acrylic-modified earthen mortar used at three prehistoric Pueblo sites", Conservation Program, 
Intermountain Cultural Resource Center, Intermountain Field Area, National Park Service, Dept. of the 
Interior, Santa Fe, NM, 1996. 

93 Dix, Linnaea A. "Characterization and analysis of Prehistoric earthen plasters, mortars, and paints from 
Mug House, Mesa Verde National Park Colorado", University of Pennsylvania Masters Thesis, 1996. 

94 Slater, Mary E. "Characterization of earthen architectural surface finishes from Kiva Q, Cliff Palace, 
Mesa Verde National Park Colorado", University of Pennsylvania Masters Thesis, 1999. 

95 Mueller, Urs. "Final Report", The Getty Conservation Institute. Los Angeles, CA, 1 1/29/2001. 

96 Beas, Maria Isabel G. "Traditional architectural renders on earthen surfaces", University of Pennsylvania 
Masters Thesis, 1 99 1 . 

97 Bass, Angelyn. "Design and Evaluation of Hydraulic Lime Grouts for in Situ Reattachment of Lime 
Plaster to Earthen Walls", University of Pennsylvania Masters Thesis, 1998. 

98 Fong, Kecia Lee. "Design and Evaluation of Acrylic-Based Grouts for Earthen Plasters", University of 
Pennsylvania Masters Thesis, 1999. 

84 



finishes. First, significant physical properties for plaster formulation were identified. 
The same was done to identify the material properties of the adhesive formulation 
currently used in-situ. Next, a sequence of testing was conducted to assess the effects of 
accelerated weathering of these materials and to assess their interaction with one another. 

Factors that were considered in the assessment of original plaster formulations 
included particle size distribution, particle shape, petrographic and elemental analysis, 
color, pH, salt content and carbonate content. These same properties, plus an assessment 
of soil density and plasticity were also noted for locally obtained soils. Further tests to 
assess the effects of environmentally induced shear stress to strain coefficients were 
conducted for this study. 

To assess the material properties of the University of Pennsylvania's adhesive 
treatment formulation cure time, cohesive shrinkage, viscosity, reflectance, flexibility, 
glass transition temperature, vapor transmission and bond strength were each tested. 
Research was conducted in the fields of biochemistry, photographic conservation, adobe 
preservation, food science and fine arts painting conservation. Detailed conditions 
mapping also revealed the short-term effects of environmental weathering. To test the 
physical interaction between the adhesive and native materials used in plaster 
manufacture, initial visual observations were combined with measurements of the shear 
force needed to detach readhered facsimile plasters that were detached from their 
substrates. 

The testing program began with the production of reproduction plaster and wash 
layers applied to facsimile substrates. Layer thickness, granulometry and porosity of the 

substrates were based on previous analysis of Mesa Verde earthen renders. Both brick 

85 



and sandstone were used as facsimile substrates. Each substrate was tested to determine 
its percent porosity prior to plaster application. The seven samples were prepared 
according to the ASTM D 4062-99 Standard Test Method for Leveling of Paints Draw- 
Down Method, slightly modified to accommodate the thickness of a masonry substrate. 
Though the method of application was the same, an adjustable draw-down tool was 
constructed that is able to produce uniform surface finishes on various thickness of 
substrate. Each of the samples was prepared the same way except for Sample X. All 
substrates were cut to a thickness in the range of 16-23 mm. with a diamond bit, water 
lubricated rotary saw. The thickness of plaster layers was gauged according to ASTM D 
41 38-94(200 l)el Standard Test Methods for Measurement of Dry Film Thickness of 
Protective Coating Systems by Destructive Means. The underlying coat of reddish brown 
plaster was formulated with a sand:silt/clay ratio of 65:35 and was applied at a thickness 
within the range of 1.2-1.3 mm. The top layer of wash consisted of a 35:65 sand: silt/clay 
ratio applied at a thickness of 0.4-0.5 mm. Sample X was a thin slice of sandstone that 
was coated with four layers of plaster. The first layer was a mixture of the reddish brown 
(SY-3) soil mixed with the same ratio as above. The second layer was made from the 
same mixture of very pale brown (S Y-2) soil and was followed with a layer of white soil 
(SY-1). The white soil consisted of 50% very pale brown sand, 30% very pale brown silt 
and 20% white silt. 

The intention of these tests was to try different variations of temperature and moisture 
cycling to determine a method most likely to produce the blistered and delaminated 
condition that is common at Mesa Verde. These experiments were terminated once the 
samples showed a sign of either blistering or cracking. 



12.1 Viscosity Test 

Samples of each of eight solutions were subjected to three tests with appropriate 
Zahn viscosity cups. Tests were conducted according to ASTM D 4212-99 Standard Test 
Method for Viscosity by Dip-Type Viscosity Cups. The solutions were heated and cooled 
numerous times throughout the experiment in order to obtain exact temperatures for 
testing. However, this should not induce a high margin of error because each solution 
was subjected to the same procedure. Viscosity tests of gelatin based solutions at colder 
temperatures were attempted with Zahn cups #3 and #4. However, the gelatin did not 
solidify uniformly throughout the solution at a consistent rate. Thus, interruptions in 
flow of the solution affected the timing of these tests producing inconsistent results. Since 
the viscosity of gelatin-based solutions vary with slight temperature changes between 20- 
25 degrees Celsius, additional tests were conducted at higher temperatures for the gelatin- 
based solutions. Ambient temperature during the course of this experiment was 21°C 
with 22% relative humidity. 



87 



TABLE 23 
Viscosity of Treatment Solutions 



Comparison of Solution 
Viscosities 



^ 60 

s 50 

co 40 

8 30 

» ?8 

> 10 

^ 









C# c# G° G° ^° ^° A& J& 



\* 



n> 



Solution 



KEY 

5%GW = 5% Gelatin in water 

10%GW = 10% Gelatin in water 

5%GG = 5% Gelatin with 10% Glycerin in water 

10%GG = 10% Gelatin with 10% Glycerin in water 

5%MC = 5% Roplex MC-1834 in water 

10%MC = 10% Roplex MC-1834 in water 

5%E = 5% Roplex E-330 in water 

10%E = 5% Roplex E-330 in water 



The acrylic emulsions were less viscous than the gelatin solutions, which explains 
why the acrylic solutions were more likely to cause staining when applied in the field. 
Staining was likely caused by the more thorough coverage of soil particles and reverse 
migration of the suspended solids. The viscosity of acrylic emulsions tested was 
equivalent to the viscosity of de-ionized water without the added adhesive component. 
Viscosity of the gelatin solutions varied according to the percentage of gelatin within the 
solution. Other determinants of viscosity of gelatin solutions that were not specifically 
tested include temperature, molecular weight and hydrogen-ion concentration." The 
molecular weight of gelatin varies from 20,000 to 250,000 100 and has a direct impact on 
the adhesive bond and gel strength of a gelatin solution. "The lower the mean molecular 
weight (MW) of a gelatin the lower the gel strength and viscosity of its solution, however 
it has been shown that the collagen alpha-chain is the main contributor of gel strength and 
that higher molecular-weight components make a relatively low contribution to gel 
strength but a high contribution to viscosity... In general one can say that the lower the 
mean molecular weight (MW) of a gelatin the lower the gel strength and viscosity of its 
solution." Since the molecular weight of gelatin can vary greatly depending on the raw 
materials used and method of manufacture, viscosity is an important factor in 
determining the adhesive capability of a gelatin solution. Thus, a major factor for 



Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/gltnl.html 
100 Matt T. Roberts, Don Etherington and Margaret R. Brown. "Bookbinding and the Conservation of 
books: A Dictionary of Descriptive Terminology", Stanford University Libraries, 1994. 
http://palimpsest.stanford.edu/don/don.html 

' Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/gltnl.html 

89 



assessing commercial grades of gelatin is the calculation of viscosity by a mathematical 
model to calculate Bloom. 

Most gelatin-based films require a low viscosity to enable wetting and coverage of 
the adherent surfaces. Addition of a gelatin plasticizing agent lowered the viscosity of a 
10% Gelatin solution. Based on the results of this test, the higher the concentration of 
gelatin within the solution, the higher the temperature needed to obtain equivalent 
amounts of viscosity. 

12.2 Set Time 

This test was loosely based on D 2471-99 Standard Test Method for Gel Time and Peak 
Exothermic Temperature of Reacting Thermosetting Resins and D 4640-86(2001) 
Standard Test Method for Determining Stroke Cure Time of Thermosetting Phenol- 
Formaldehyde Resins and D 4473-01 Standard Test Method for Plastics: Dynamic 
Mechanical Properties: Cure Behavior and D 3056-00 Standard Test Method for Gel 
Time of Solventless Varnishes. In additional, a glazed ceramic spot test plate was filled 
with a 0.05 cc. of each solution. The ambient environment was 21° Celsius at 22% 
relative humidity. The tray was placed in the vent hood and samples were monitored on 
an hourly basis. The following solutions were tested: 5% Rhoplex E-330in water (5%E), 
10% Rhoplex E-330in water (10%E), 5% Rhoplex MC-1834in water (5%MC), 10% 
Rhoplex MC-1834in water (10%MC), 5% Gelatin in water (5GW), 10% Gelatin in water 
(10%GW), 5% Gelatin with 10% Glycerin in water (5%GG), 10% Gelatin with 10% 
Glycerin in water (10%GG). 



90 



Observations at 1 hour: 

All gelatin solutions were in solid/gel form containing approximately the same 
volume as they did in liquid form. The acrylic solutions were approximately 75% 
evaporated as determined through visual examination. A cracked film had formed on the 
surface of 10%MC and an extremely thin, uncracked film had formed on the surface of 
the 10%E. 

Observations at 2 hours: 

Gelatin solutions were still in solid/gel form and only 25% of the original volume 
had evaporated. All acrylics had more than 75% evaporated and a surface film has 
formed on each sample. 

Observations at 3 hours: 

More than 75% of all solutions had evaporated. All acrylic solutions were white, 
rigid films adhering to the surface of the ceramic test plate. Gelatin solutions in water 
formed thin, rigid films that cohesively pulled up from the bottom of the test plate 
forming their characteristic air bubble beneath them. Gelatin in water solution films were 
of a transparent, slightly yellow coloration. Gelatin and glycerin solutions adhered to the 
surface of the test plate, were transparent and remained tacky to the touch. 

Observations at 4 hours: 

Same as observations at 3 hours except that the acrylic films changed to a clear 

coloring. One method for establishing the grade of gelatin used in a solution is the 

determination of Gel/Bloom Strength. This is determined as follows by measuring the 

force needed to compress a specified amount of gelatin while in a gelatinous state. 

Laboratory methods for establishing the Bloom Strength are outlined in British Standard 

91 



757 of 1975 and in the Standard Methods for sampling and testing gelatin, published by 
theGMIA. 102 

12.2.1 Glass Transition Temperature 

Previous studies of the glass transition temperature of gelatin determined their 
liquid limit to be 35° Celsius and solid limit to be at 10° Celsius. The term glass 
transition point is commonly used to describe the point where a film converts from a 
liquid to a solid. For gelatin solutions, the transition from a liquid to a solid is dictated by 
two factors. The initial transition from liquid state to solid for this treatment is dictated 
by temperature while the final transition is the result of solvent loss through evaporation. 
Testing was conducted to determine the temperature that liquid gelatin formulations form 
a gelatinous mass. This gel point was recorded for each gelatin based solution used in 
this study. The test was conducted at an ambient temperature of 66 degrees Celsius at 
42% relative humidity. This test was conducted by warming 500 ml of each solution to 
attain a fully liquefied state. The solutions were then left to cool. Solutions were stirred 
every fifteen minutes with a glass stirring rod. Temperatures were recorded at the point 
when gelatinous solutions became solid enough to support the glass stirring rod in a 
vertical position within the solution. This test produced the following results. 



Cole, Bernard. "Gelatine Food Science", University of Pretoria, http://www.gelatin.co.za/gltnl.html 

92 



Liquid to Gel/Solid Transition Point 

• 5% Gelatin in water = 2 1 degrees Celsius 

• 10% Gelatin in water = 23 degrees Celsius 

• 5% Gelatin and 10% Glycerin in water = 24 degrees Celsius 

• 10% Gelatin and 10% Glycerin in water = 24 degrees Celsius 

12.3 Reflectance Test 

Observations were made according to ASTM D 4449-90 Standard Test Method 
for Visual Evaluation of Gloss Differences Between Surfaces of Similar Appearance with 
Lamp B as specified in this test. Reflectance was most noticeable with the lamp positions 
at a 90-degree angle to the specimens and located 10 inches above them. Observations 
were made at a 45-degree angle to the specimens. Observations were recorded on a scale 
of 0-5 with 5 having the most reflectance and having no visible reflectance. 
Microscopic observations were made one week after treatment. Samples 1-3 were tested 
with solutions heated to a temperature of 65 degrees Celsius (see table 24). 



93 



TABLE 24 
Test Data for Assessing Reflectance 



Form- 
ulation 


Sample #1 - 


White Wash 


Sample #2 
Brown Plaster 


Sample #3 - 


Brown Wash 


Dry 

Substrate 


Pre-wet 
Substrate 


Dry 

Substrate 


Dry 

Substrate 


Pre-wet 
Substrate 


1%MC 

















3%MC 





1 


1 


1 





5%MC 


2 


3 


2 


3 


1 


10%MC 


5 


4 


3 


4 


3 


1%E 

















3%E 


2 


2 


1 


1 





5%E 


3 


3 


3 


3 


2 


10%E 


5 


4 


4 


4 


3 



Both the 5% and 10% mixtures of gelatin without glycerin on white plaster shrank 
upon cure when applied to dry calcium carbonate plaster. Thus, their cohesive strength 
was stronger than that of the wash resulting in cracks and flaking where the solution was 
in contact with the wash. The reddish brown surface finishes exhibited less reflectance 
than the white wash did. The reddish brown plaster, formulated with a larger amount of 
sand sized particles exhibited less reflectance than both of the wash samples. As 
predicted, a higher the percentage of acrylic produces an increase in reflectance (see table 
25 and 26). 



94 



TABLE 25 
Reflectance of Acrylics when Applied to Earthen Surface Finishes 

Comparison of Acrylic Reflectance 




White Wash Red Wash Red Plaster 
Dry Substrate 



■ 1%MC 

■ 1%E 

□ 3%MC 

■ 3%E 

■ 5%MC 

□ 5%E 

■ 10%MC 

■ 10%E 



TABLE 26 
Comparison of Reflectance Ratings for Adhesive Formulations 

Comparison of Reflectance Ratings 




DSample#1 - 
White Wash 



ISample#2 - 
Brown Plaster 



□ Sample #3 - 
Brown Wash 



1%MC 1%E 3%MC 3%E 5%MC 5%E 10%MC 10KiE 

Formulation 



95 



During the gloss test, it was noted that shrinkage cracks and detachment occurred 
where the treatment contacted the surface finish. In the field, solutions are used within 
the temperature range from 10°-40° Celsius. Applications recorded as "hot treated" are 
heated on site to a temperature of approximately 35° - 37° Celsius. "Cold treated" 
applications are injected at a temperature range of 21° - 26° Celsius depending on the 
concentration of the treatment solution. Thus, two subsequent tests were conducted. 
The first was a test to determine the effects of temperature on the cohesive contraction of 
gelatin solutions. Observations were recorded as follows: No Cracks, Micro-Cracks, 
Macro-Cracks, and Detached. Microscopic observations were made one week after 
treatment (see tables 27 and 28). 



TABLE 27 
Size of Cracks formed by Unrestrained Cohesive Shrinkage of Adhesives 



Cohesive Shrinkage Cracking 

— . . , . 



BSu, 




• 1 % G W 
■ 1 % G G 



30 40 

Tem perature 



96 



TABLE 28 
Shrinkage Observations for White Wash Sample #4 



Temperature 


10%GG 


10%GW 








20 Degrees Celsius 


Micro-Cracks 


Macro-Cracks 


30 Degrees Celsius 


Micro-Cracks 


Macro-Cracks 


40 Degrees Celsius 


Micro-Cracks 


Macro-Cracks 


50 Degrees Celsius 


Macro-Cracks 


Micro-Cracks 


60 Degrees Celsius 


Macro-Cracks 


Macro-Cracks 


70 Degrees Celsius 


Detached 


Detached 



12.4 Shrinkage of Solutions 

A second test was conducted to determine any difference in cohesive shrinkage 
cracking between solutions of gelatin with glycerin (as an added plasticizer) and solutions 
of gelatin without an added plasticizer. Ambient conditions during treatment was 22°C 
and there was 30% relative humidity. Temperatures selected for this test were within the 
range where these solutions begin to gel. Observations were recorded 24 hours after 
treatment at 23 °C with 20% relative humidity and at one week after treatment. They were 
recorded according to the following scale: No Cracks, Micro-Cracks, Macro-Cracks and 
Detached. Microscopic observations were made at 30X magnification. 

The treatment that is currently in use at Mesa Verde is formulated with a protein 
binder that consists of reagent grade gelatin, often mixed with the alcohol glycerin. This 
formulation is common. As Thorton explains, "It has long been understood that glycerin 
added to animal glue will give it greater toughness and elasticity when dry. If glycerin is 
added in sufficient quantities (a 1:1 dry glue weight to plasticizer volume mixture ), it 

97 



will prevent the glue from hardening altogether, the result being a rubber-like 
substance." The effectiveness of this plasticizing additive was exhibited in the 
materials testing conducted for this study. Gelatin is a polymer that may physically bond 
with glycerin when combined into solution. However, the two components of this 
solution do not crosslink on a chemical level at room temperature. 104 When applied to the 
nonabsorbent substrate of a spot-test plate, the gelatin and glycerin remained suspended 
within the solution. However, it may be possible for these physical bonds to be broken. 
The effectiveness of glycerin as a plasticizing agent is dependant upon the strength and 
durability of these physical bonds. 

Therefore, this test was run two times. The first attempt at this test used solutions 
that had been heated, cooled and reheated numerous times before being used. The results 
of that initial test were inconsistent with the results found when the same solutions were 
applied to a glazed ceramic substrate. During this initial test, both plasticized and 
unplasticized gelatin solutions exhibited cracking at the junction between adhesive and 
substrate. One possible cause is that when plasticized solutions are applied to a desiccated 
substrate, the glycerin absorbs into the substrate at a more rapid rate than the gelatin 
resulting in the same results for both solutions. Another explanation may be that the 
warming and cooling of this solution induced evaporation thus changing the percentage 
of each component within the solution. Since human error could not be ruled out, the test 
was conducted again with newly mixed solutions. 



103 Thornton, Jonathan. "A Brief History and Review of the Early Practice and Materials of Gap-Filling in 
the West", Journal of American Institute for Conservation 1998, Volume 37, Number 1, Article 2, p. 3-22. 

104 Personal Communication with Lee Jhong, Rheaological Chemist and speaker at the 3 l sl International 
Symposium of Archeometry, 3/5/2002. 

98 



The results of this second test consistently revealed that the cohesive strength of a 
gelatin solution that does not contain a plasticizing additive such as glycerin is much 
greater than the cohesive strength of the earthen surface finishes. This results in cracks 
forming where the forces of internal contraction within a gelatin formulation are stronger 
than the cohesive forces within the finish layer. Since the cohesion within a finish layer is 
stronger than the adhesion between one layer and the next, there is a plane of weakness 
between each layer of surface finish. When subjected to external stresses, the resulting 
fracture often occurs at this plane. The differential rate of contraction for unplasticized 
gelatin formulations and surface finishes resulted in crack formation at the boundary of 
the treated area and interfacially along this plane of weakness. The 10% gelatin solution 
in water contracted so much as it set that, within a week, most of the treated areas where 
solution was originally applied to a sound substrate of surface finish had detached 
completely and exhibited finish loss. This effect makes it clear that use of an 
unplasticized gelatin solution is inappropriate in conditions where the gelatin is subjected 
to fluctuations in temperature and relative humidity. In fact, without the addition of a 
plasticizer in gelatin solutions, this adhesive could cause deterioration of surface finishes. 

This consideration should not be lost when determining the percentage of plasticizer 
to gelatin within a solution. Both gelatin and glycerin retain moisture within the structure. 
Unlike colorless gelatin that is precipitated from salts or alcohol, gelatin produced by 
changes in pH or temperature has a yellow cast to it when solid. This yellow gelatin is 
documented to retain 15-18% water in solid, dry form, making it more flexible. 105 Over 



Roberts, Matt T. and Don Etherington. "Bookbinding and the Conservation of books: A Dictionary of 
Descriptive Terminology", Stanford University, 2001. http://palimpsest.stanford.edu/don/don.html 

99 



time, the amount of water that gelatin is able to retain within its structure may change, 
making this adhesive more brittle. The effects of gelatin embrittlement are documented in 
numerous studies for the conservation of historical oil paintings. The pH of the gelatin 
also affects its hardness, which may be a factor in the embrittlement of gelatin used for 
painting and bookbinding. "Hardness of the gel is a maximum at pH 8.5 and decreases on 
either side of this pH." 106 Gelatin and glycerin are not chemically bonded when 
suspended within this adhesive solution. They are physically attracted to one another, but 
with time, the glycerin may be absorbed into the substrate leaving the gelatin 
unplasticized. This is one instance where the acrylic solutions are more practical because 
they are chemically bound, otherwise known as internally plasticized. Research is 
currently being conducted to test the crosslinking of gelatin solutions with acrylics. 

Due to surface finish detachment and cracking observed while testing for reflectance 
and cohesive shrinkage, the penetration of gelatin solutions could be observed. Amounts 
of solution were applied to the surfaces of reproductions made up of a 4-mm-thick plaster 
overlaid with a 1-mm wash layer. The solution never penetrated into the plaster layer. 
Thus, these gelatin solutions did not penetrate more than 1 mm into the reproduction 
surface finishes. This was evidenced because as the gelatin solutions cured, they 
contracted and lifted up from their plaster substrate. When applied to plaster without a 
wash, gelatin solutions did not lift from the surface but microscopic cracks did occur. 
For more data regarding this test refer to Appendix F. 



106 Roberts, Matt T. and Don Etherington. "Bookbinding and the Conservation of books: A Dictionary of 
Descriptive Terminology", Stanford University, 2001. http://palimpsest.stanford.edu/donydon.html 

100 









Figures 18 and 19. Shrinkage cracks formed Figure 20. Testing apparatus 
by unplasticized gelatin for Shrinkage and Reflectance 

12.4.1 First Test for the Relative Shrinkage of Solutions 

A sample of 3 cc. solution of each material was placed in a black glazed ceramic spot 
test plate. The acrylics were applied at a temperature of 23 degrees Celsius and the 
gelatin solutions were applied at 35 degrees Celsius to ensure fluidity. The atmospheric 
temperature at the time of application was 23 degrees Celsius and the relative humidity 
was 35%. Observations were made 96 hours later at an atmospheric temperature of 21 
degrees Celsius and 41% relative humidity. Observations were based on tactile, visual 
and volumetric comparison. Visual comparisons were made with the naked eye and 
microscopically. Multiple tests of each of the following were made for relative 
comparison. 

Observations: 

The gelatin in water solutions formed a rigid, hard, cohesive film that adhered to 
itself better than it adhered to the glazed ceramic substrate. Due to the cohesive nature of 

this solution, an air bubble formed on the underside of the film in every sample. The size 

101 



of air bubbles formed below films of the 10% solution were visually approximated at 
twice the size of that formed with the 5% solution. The cohesive nature of the gelatin 
films effectively sealed the solution underneath from the air. Thus, even after 96 hours, a 
portion of the 5% solution was not fully cured, but instead was trapped in the bubble 
underneath a rigid film. Only as the gelatin contracted cohesively, did the sides of this 
film pull away from the walls of the cup exposing the solution beneath it to the air and 
thus allowing it to cure. 

Gelatin with glycerin used as an additive formed a less rigid but just as cohesive 
film. No air bubble was trapped beneath the film. Furthermore, the film remained tacky 
to the touch 96 hours after the solution was applied. 

Both acrylic resins formed hard films that were less cohesive than the gelatin 
solutions. All acrylic films cracked as they set and no air bubbles were formed. This 
reaction can be explained by applying the model of evaporative drying used to explain 
the cracked appearance of some latex paints. "As the film dries from the surface down, a 
fixed film area is then subject to contraction in the z-plane, thereby producing stress in 
the x-y plane. If polymer elasticity is insufficient, then the stress can be overcome by 
slippage between the coalesced layer and the fluid beneath giving rise to the 'mud- 
cracked' surface effect." 1 

12.4.2 Second Test for the Relative Shrinkage of Solutions 
An additional test was conducted by putting 9 cc. of each adhesive into a 50 ml. 
graduated cup. The shrinkage of each sample was rated from 0-10 with 10 denoting the 



107 Roberts, Matt T. and Don Etherington. "Bookbinding and the Conservation of books: A Dictionary of 
Descriptive Terminology", Stanford University, 2001. http://palimpsest.stanford.edu/don/don.html 

102 



most shrinkage and denoting the least amount of shrinkage once cured. Volumetric data 
was obtained by recording the number of cc. needed to fill the cup, atop of the dried film, 
to achieve the same level of fullness. Observations of volume loss were made 336 hours 
later at an atmospheric temperature of 20° Celsius and 17% relative humidity. 

TABLE 29 
Test Data for Volumetric Shrinkage Test 



Sample Solution 


Volume Lost (cc. of solution) 


5% Gelatin in Water 


8cc. 


10% Gelatin in Water 


8cc. 


5% Gelatin with 

10% Glycerin in Water 


8cc. 


10% Gelatin with 
10% Glycerin in Water 


8cc. 


5% E-300 in Water 


7 cc. 


10% E-330 in Water 


7 cc. 


5%MC-1834inWater 


7 cc. 


10%MC-1834inWater 


7.5 cc 



Studies have shown that swelled gelatin is able to retain ten times its dry weight 
in moisture when in gel form. 108 Yet in solid form, there was little difference between 
the gelatin and acrylic-based solutions. Thus, the material properties of gelatin solutions 
are equivalent to that of acrylic solutions when not exposed to great fluctuations in 
temperature and relative humidity. Unfortunately, climate control is not possible in the 
field. 



103 



12.5 Expansion. Contra ction and Flexibility of Adhesive* 

To provide a relative comparison of how each formulation would react to the 
wetting and drying cycles it might be exposed to in the field, each of the cured solutions 
used in the first test for relative shrinkage were rewetted with 2.5 cc of water retained at a 
temperature of 10° Celsius. The solutions were left to soak in this water bath for 24 
hours, then observed. Once dry, they were again rewetted one more time. Both visual 
and tactile observations were made when the solutions were fully dry. The following 
solutions were tested: 10% gelatin in water, 10% gelatin with 10% glycerin in water, 10% 
MC-1834 in water, 10% E-330 in water (see figures 21). 




10% Gelatin 
Diluted in Water 



10% Gelatin & 10% Glycerin 10% Rhoplex E-330 

Diluted in Water Diluted in Water 



10% Rhoplex MC-1834 
Diluted in Water 



Figure 2 1 . Spot Test Plates Containing Cured Adhesives 



12.5.1 Acrylic solutions 

While wet, the acrylic solutions resumed their white color but did not return to 
solution (see figure 22). Upon drying, the adhesive films exhibited the same transparent 
color and the same "mud-cracking" that occurred during the initial cure of these films. It 
is notable that the acrylic films were able to be removed from the ceramic spot plates 



Cassar, JoAnn and Roberta de Angelis. "Glossary. Materials used in 19th and 20th century Plaster 
Architecture. Plaster Architecture Essay, Culture 2000 Programme of the European Union. 
http://www.plasterarc.net/essay/essay/CassarG.html 

104 



only after soaking and vigorous scrubbing. Thus, removal of acrylic adhesives with a 
solution consisting solely of water would not be reasonable in the context of earthen 
surface finishes. 

12.5.2 Unplasticized gelatin solutions 

This was the only solution that did not remain closely adhered to itself throughout 
the duration of this experiment. Cohesive contraction of this gelatin solution during its 
initial cure caused it to pull away from the ceramic dish. Each successive wetting and 
drying episode caused the unplasticized gelatin film to exacerbate this affect by pulling 
up from the center of the cupped portion of the ceramic spot plate. By the end of the 
second wetting and drying period, the unplasticized gelatin solution had become fully 
detached from the glazed ceramic substrate. This affect was not observed for any of the 
other solution types. 

12.5.3 Plasticized gelatin solutions 

While wet, the plasticized gelatin solutions took on a yellow cast and swelled 
slightly but did not return to gel form at room temperature. The solution remained tacky 
to the touch after two wetting and drying cycles, and remained closely adhered to the 
ceramic spot plate. 



105 




Figure 22. Spot Test Plates Containing Rewetted Adhesives 



12.4.4 Elasticity 



Elasticity, commonly recorded as E-modulus in paint and adhesive formularies, has a 
highly influential affect on the performance of such films. As stress builds up 
interfacially between layers due to fluctuations in temperature and relative humidity, this 
stress causes strains that result in cracking and adhesion loss. If the adhesive is less rigid 

109 

and more flexible than the adherents, it may serve as a buffer to absorb these stresses. 
So long as the adhesive does not impose new stresses on the object being conserved, as 



109 Berger, Gustav A. and William H. Russell. "Conservation of Paintings : Research and Innovations", 
Archetype Publications: London, 2000. 

106 



the adhesive reacts to these same environmental fluctuations, elasticity is a most 
favorable quality when selecting an adhesive. As gelatin ages, it becomes more 
completely crosslinked resulting in a more rigid and brittle bond. This brittleness results 
in a loss of bond strength for the original unplasticized gelatin adhesive and a reduction 
in bond strength for future treatments as well. Materials testing published in the 
Conservation of Paintings tested the bond strength of unplasticized gelatin solutions to 
that of gelatin solutions that were plasticized with honey. u0 The results of this 
experiment exhibited no difference in bond strength (see table 30). However, the 
plasticizing effects of glycerin was not tested in this experiment. 



TABLE 30 
Materials testing to Determine the Bond Strength for Retreatment of Adhesives 



Peel test group (d): peel strength of different adhesives on 
microcrystalline was (ASTM D 903-»9) 


paint 


films impregnated 


with gelatin and 


Composition of 
adhesive 






Cleaned, 

unimpregnatcd 

control 


Paint film 


impregnated with: 


gelatin in microcrystalline 
water 1:16 wax (Victory White) 


Fish glue + honey in water 1:1:10 






failure 




failure 




failure 


Gelatin in water 1:10 

Rabbitskin glue in water 1:10 

Gelatin + honey in water 1:1:10 

Rabbistldn glue + honey in water 1:1:10 

Elvacet 1454 in water 1:2 

Thermogrip in benzine 1:3 

Beeswax, multiwax. Dammar, Venice turpentine 

Microcrystalline wax (Victory White) 


6:6:4: 


failure 

failure 

failure 

failure 

400 

750 

1 135 

100 




failure 

failure 

failure 

failure 

failure 

20 

80 

100 




failure 

failure 

failure 

failure 

failure 

30 

50 

50 


All values in grams per 12.7 mm at the cross 


-head speed 


of 1 mm/min 










Failure - spontaneous delaminarion prior to test. 















Acrylics are generally considered to be internally plasticized. An internally 
plasticized adhesive is defined as "An adhesive which has had the plasticizing agent 



Berger, Gustav A. and William H. Russell. "Conservation of Paintings : Research and Innovations", 

107 



introduced as part of the adhesive molecule during the manufacturing process, as 
contrasted with an adhesive to which the plasticizer is added by the user. The adhesive is 
copolymerized with the plasticizer to form the internally plasticized adhesive." 111 

By the definition noted above, the gelatin used in these formulations is 
unplasticized until the user adds an external plasticizing agent such as glycerin. In 
theory, the adhesive solution of 10% gelatin in water would be less elastic than the 10% 
solution that is combined with an equal percentage (weight to volume) of the plasticizing 
agent glycerin. This was proved a valid assertion in the tests conducted for this study. 

One advantage to using an internally plasticized adhesive is that adhesive agent 
and plasticizing agent will not separate without human intervention so long as they are 
stored within the normal range of environmental fluctuation. However, internally 
plasticized adhesives are often less reversible and the crosslinking of some adhesive 
formulation can eventually cause the solution to become embrittled. Crosslinking within 
unplasticized gelatin solutions can cause the embrittlement of such films thus inducing 
the damage seen in cracked oil paintings that have been sized with gelatin. Physical 
bonding of gelatin to glycerin is possible, but chemical crosslinking is not possible at 
room temperature. 1 12 

Several methods were devised to measure the elasticity of each 10% solution. 
The simplest test for elasticity was simple visual and tactile observations made during the 
course of this experiment. At the end of this experiment, the unplasticized gelatin films 



Archetype Publications: London, 2000. 

Matt T. Roberts and Don Etherington. Bookbinding and the Conservation of books: A Dictionary of 
Descriptive Terminology http://palimpsest.stanford.edu/don/don.html 

' Personal Communication with Lee Jhong, Rheaological Chemist and speaker at the 31 st International 
Symposium of Archeometry, 3/5/2002. 

108 



were already detached, and the plasticized gelatin films were carefully removed from 
their substrate with a microspatula. The unplasticized gelatin film was hard and rigid 
while the plasticized gelatin film was still elastic and pliable. 

12.6 Adhesive bond streng th 

After five cycles of accelerated weathering, 27 samples were treated with an 
adhesive solution and mechanically tested to determine the relative bond strength of such 
solutions. All samples were treated for both substrate detachment and interlayer 
detachment. 

Three reddish brown samples were treated with each of the following solutions: 

(1) water 

(2) 5% gelatin in water 

(3) 10% gelatin in water 

(4) 5% gelatin combined with 10% glycerin in water 

(5) 10% gelatin combined with 10% glycerin in water 

(6) 5% Rhoplex MC-1834 acrylic in water 

(7) 10% Rhoplex MC-1834 acrylic in water 

(8) 5% Rhoplex E-330 acrylic in water 

(9) 10% Rhoplex E-330 acrylic in water. 



109 



Three samples of white caliche finishes were also treated with these solutions: 

(1) water 

(2) 5% gelatin combined with 10% glycerin in water 

(3) 10% gelatin combined with 10% glycerin in water 

(4) 10% gelatin in water 

(5) 10% Rhoplex MC-1834 acrylic in water 

(6) 10% Rhoplex E-330 acrylic in water. 

A single seven-day cycle of weathering was conducted on all samples after 
treatment. Due to the already severely deteriorated state of these samples, the procedure 
for this weathering cycle was limited to fluctuations in the level of moisture applied to 
one half of the sample. Misting of finish surfaces was conducted hourly for the first five 
hours. Then samples were given a two-hour period to dry before being misted hourly for 
the next five hours. At the end of this seven-day cycle, all samples were examined and 
photographed. 

Since full substrate detachment was consistent for all samples prior to treatment, 
mechanical testing was conducted on treated and weathered samples to determine the 
relative bond strength of each adhesive at this juncture. Two tests were developed to 
measure the amount of shear force required to break the bond between substrate and 
plaster finish. In an effort to devise an inexpensive testing method that can be done in the 
field, a hand-held force meter was retrofitted with an attachment to disperse the force 
needed to detach the finishes from their substrate (figure 24 and 24). This method of 

detachment was effective in providing relative measurements for bond strength of 5% 

110 



solutions, except that the force needed to break a bond created with 10% solutions was 
beyond this tool's maximum capacity. For this, an Instron model 1331 was utilized. 
Both testing setups are illustrated in figures 25 and 26. 

One notable difference between the two tests is that the Instron graphs minute 
fluctuations in adhesive bond strength such as cracking of the material prior to full 
detachment. In some cases, the finishes detached in a single, intact layer. This type of 
detachment was attributed to the use of an adhesive that was weaker than the cohesive 
strength of the finishes. Other samples crumbled and cracked rather than fully detached 
from their substrate. This result was interpreted as evidence that the adhesive was 
stronger than the original finish materials. 




Figure 23. Illustration of the Testing Set up for applying force to treated Samples 



ill 




Figure 24. Adhesive bond strength testing conducted with the hand-held force meter 
















09 

ZT 


33 

03 

CD 


CO 1 

c ■ 
cr ■ 
w 1 

CD 



















































Figure 25. Adhesive bond strength testing 
with the Instron model 1331 



Figure 26. Illustration of Insron 
model 1331 testing method 



112 



A comparison of these results shows that the Rhoplex MC-1834 solutions have 
the highest bond strength. In fact, the mean value of force needed to break the adhesive 
bonds formed with a solution of 10% gelatin and 10% glycerin in water is equivalent to 
that needed to break a bond formed with a solution of 5% Rhoplex MC-1834 in water 
(see table 31). The difference between a 5% and 10% solution of Rhoplex MC-1834 was 
more than double while the same increase in solids content for Rhoplex E-330 resulted in 
a nominal increase in bond strength (see table 32). 

Visual comparisons of fractures induced by this indicated a tendency for both 
10% gelatin solutions and the 10% MC-1834 acrylic solution to suffer fractures within 
the plaster and wash layers before the plaster layer fully separated from its substrate. This 
indicates that either the adhesive is stronger than the adherents that it bonds or that the 
sample was so weathered that it fractured along flaws that already existed within the 
reproduced surface finishes. If this first assumption is correct, the cohesive strength of 
weathered reproduction plaster layers lies just under 300 pounds of force. Furthermore, 
the crumbling observed to occur with samples that were treated with a solution of 10% 
gelatin in water crumbled differently from those of the other samples (see figure 113). 
While the unplasticized 10% gelatin solution crumbled into small fragments, the 
plasticized gelatin solution and MC-1834 acrylic solution each retained their original 
form despite the new cracks and delamination that occurred. This is significant because 
it may indicate that earthen plasters that are treated with the gelatin with glycerin may be 
more resistant to losses caused by physical impact than surfaces treated with an 
unplasticized gelatin solution. 



113 




Figure 27. Sample exhibiting fractures that indicate a stronger adhesive 
bond strength that the cohesive strength of the surface finishes 

Further deterioration occurs because the use of less binder allows more moisture 
to penetrate it. The ratio of particle content to binding medium determines how well the 
particles are coated with binding medium. An excess of binding medium can serve as a 
sealant by filling the pores of both surface finishes and substrate. Since wash layers are 
formulated with a greater quantity of clay and silt sized particles, they are less porous 
than paints with larger particle sizes. When water enters the masonry substrate by means 
of rain, percolation or capillary action it is retained at the plaster-to-wash interface 
because the plaster formulation allows for more moisture permeability than the wash 
does. When the wash is not chemically formed through crystallization, these small 
binding particles are free to expand with the retained water. This expansion increases the 
rate of isolated detachment between plaster and wash that is characterized by blistering. 



114 



TABLE 31 
Comparison of Bond Strength for 5%GeIatin to 5%Acrylic Formulations 



Five Percent Adhesive Solutions 



(A 

T3 
C 
3 
O 

Q. 




Water 5% GW 5% GG 5% E 5% MC 
Adhesive Solution 



TABLE 32 
Comparison of Bond Strength for 10%Gelatin to 10%Acrylic Formulations 



Ten Percent Adhesive Solutions 




600/ 


fSm 




Pounds of 
Force 


/, 
% 
/ 
/ 






IF 




fSt 








i • 








1 ■ yWTTJ 




Water 1 
C 

A 


3% 


10% 10% E 10°/ 
GG MC 

sive Solution 


3 





115 



12.7 Vapor Transmission Test 

Procedures for this experiment are outlined in ASTM D 1653-93 Standard Test 
Methods for Water Vapor Transmission of Organic Coatings, Test Method B. Eighteen 
samples of 60:40 sand:silt/clay ratio were cast to form circular discs of a 1.5 cm. 
thickness and a diameter of 8 cm. Samples disks were allowed to sit in 30%RH for 72 
hours after air-drying. Coatings were applied with a camel-hair brush in two successive 
coatings applied at 90° angles from one another. After another 72 hours of drying in a 
desiccator maintained at 20° Celsius and 30% relative humidity. Samples were sealed in 
plastic bags and transported to the testing site. Plastic cups were weighed and filled with 
180 ml. of water each. Sample disks were removed from their protective bags, weighed, 
placed on top of cups containing water and then secured in place with paraffin wax. A 
recording of temperature and relative humidity was taken at each 24-hour cycle and noted 
in appendix I. 

Water vapor transmission rate can be calculated as the slope of a graph plotting 
the weight loss over time and dividing this number by the surface area of the treatment. 
For the purposes of this study, the mean water vapor transmission rates listed in table 33 
are recorded in terms of grams per meters 2 per 24 hours. This experiment indicates that 
the rate of water vapor transmission is similar for all adhesive formulations tested. 



116 



TABLE 33 
Water Vapor Transmission - Summary of Test Data 



Sample 


Weight 
Change for 
Sample 1 
(g) 


Weight 
Change for 
Sample 2 
(g) 


Weight 
Change for 
Sample 3 
(g) 


Mean 

Weight 

Change 

(g) 


Time 

(h) 


Surfac 
e Area 
(m 2 ) 


Water Vapor 
Transmission 
Rate 


Control 


34.6 


41.3 


35.1 


37.0 


572 


0.005 


12.9 


10% 
GW 


27.0 


30.3 


28.8 


28.7 


572 


0.005 


10.0 


5% GG 


25.6 


31.7 


26.5 


27.9 


572 


0.005 


9.8 


10% 
GG 


21.2 


29.2 


26.0 


25.5 


572 


0.005 


8.9 


10% 
MC 


33.5 


31.9 


26.9 


30.8 


572 


0.005 


10.8 


10% E 


24.9 


28.0 


27.7 


26.9 


572 


0.005 


10.2 



TABLE 34 
Average Water Vapor Transmission Rates 



310.0 

£ 300.0 

■jj? -^290.0 

£ E 280.0 

£ 2270.0 
q, O) 

E ^260.0 

w 250.0 

240.0 



Mean Sample Wieght of Vapor 
Transmission Samples 




Control 
10% GW 
5% GG 
10% GG 
10% MC 
10%E 



Time (hours) 



117 



Chapter 13 
REVERS ABILITY 

The principle of reversibility is essential in the selection of any stabilization 
treatment performed by responsible conservators. This is a difficult criterion to attain 
since the very purpose of treating an object is to change its natural course of 
deterioration. As stated by Appelbaum, reversibility 



does not require that the object be identical to what it was, only that 
we can return it to a state where our treatment choices are as broad as 
they were before the treatment in question was performed. 113 



Future technological innovations are likely to provide new and better methods for both 
stabilization and analysis. Yet, this must be balanced with current threats to the resource. 



Even if an internal consolidant is easily soluble, it is unlikely that much can 
ever be removed, particularly since objects that need consolidation are by 
definition so weak that repeated applications of solvent may cause 
damage... Even a minor treatment like injecting warm gelatin under loose 
flakes of paint is not reversible, as there is no physical access to the gelatin 
lodged between the layers of paint after the paint is laid down... An equally 
important question is: what will happen when the piece needs treatment 
again, particularly if the problem that necessitated the treatment recurs? 
Can the same treatment be repeated? Can a different material be used with 
the first one still in place? What can be done with written condition and 
treatment records to make it more likely that a future conservator can find 
out what was done? The undertaking of an admittedly irreversible 
treatment does not absolve the conservator of responsibility for the future 
of the object, but increases the importance of a factor we might call, for 
want of a more elegant term, "re-treatability." The notion of re-treatability 



113 Barbara Appelbaum. "Criteria for Treatment: Reversability", ", Journal of the American Institute for 
Conservation, Volume 26, Number 2, Article 1, 1987, p. 65-73. 

118 



is one that is often more helpful in evaluating treatments than the idea of 
reversibility itself. This is particularly true in the impregnation of badly 
deteriorated materials, since the treatment strengthens what is left of the 
object but may not prevent further deterioration of original material, and re- 
treatment may not be far in the future. 114 



Animal proteins have been used for years in the field of objects conservation. 
Thus, the methods for their retreatment are well documented. Hide glue was used in a 
variety of applications; possibly the most well documented is in the priming of canvases 
with Gesso prior to the application of oil paint. The main problem experienced with 
gelatin adhesive solutions is that they become brittle with age. As the gelatin becomes 
more brittle, it loses adhesion. Materials testing of adhesives for the consolidation of oil 
paintings has found that the bond strength is less for retreatment with gelatin solutions to 
a gelatin based gesso substrate than it is with acrylic solutions to a gelatin based gesso 
substrate. 

Removal of adhesive solutions can be a complex issue. Even in cases where the 
adhesive formulation is readily soluble, that does not damage either the paint or the 
substrate, dissolving the adhesive after it has been applied requires heat and agitation. 
Agitation is impossible once this adhesive has been applied to in-situ. Without agitation, 
treated areas would require heat and water to melt the gelatin. Unfortunately, heat and 
water would subject the gelatin to swelling and would reactivating the earthen finishes. 
Therefore, the removal of gelatin solutions may cause further damage to the earthen 
surface finishes. 



114 Barbara Appelbaum. "Criteria for Treatment: Reversability", ", Journal of the American Institute for 
Conservation, Volume 26, Number 2, Article 1, 1987, p. 65-73. 

119 



While conducting these treatments, conservators have developed methods to 
reduce the potential affects of reverse migration. By rewetting original plasters, carbon 
may migrate to the surface, appearing as stains on the outermost surface finishes. This 
affect can be seen in the field when the water from treatment applications result in dark 
stains on the surface of the plaster. In 2000, two interns working for the University of 
Pennsylvania developed a method for countering this affect. An application of 
cyclododicane is currently used to block the migration of such solutions from reaching 
the surface of the earthen finishes. 115 

However, it should be noted that since gelatin is a biodegradable adhesive that 
becomes brittle with age, treated areas will eventually lose their adhesion. Other studies 
have cited that retreatment with gelatin does not provide a bond with the same strength as 
was originally established. Thus, though retreatment is feasible, further testing needs to 
be done to establish the best method for retreatment. 

Numerous wet chemical methods have been developed to determine the presence 
of proteinacoius binders such as the biochemical biuret test, or testing with 
givestrichloroacetic acid, tanic acid or ninhydrin. The precipitate with 5 % tannic acid is a 
particularly sensitive test for very dilute solutions of gelatin. X-ray diffraction and 
differential scanning calorimetry are other methods commonly used to detect protein 
conformation changes." 6 Testing of original plasters for protein content yielded negative 
results and personal communications with representatives from the Hopi asserted that no 



115 Personal communication with Brynn Bender, objects conservator, 2001 field season. 

116 Messier, Paul. "Work In Progress: An Analysis of the Effect of Water on the Cracking of Albumen 
Photographs", Topics In Photographic Preservation, Volume 4, Compiled by Robin E. Siegel, American 
Institute for Conservation of Photographic Materials Group, 1991. 

120 



proteins were mixed into their traditional earthen plasters. Thus, a positive result for 
protein could indicate that conservation treatment had occurred at this location. When 
this test yeilds a positive result, it provides conservators with an additional method to 
determine the locations of previous treatments. 117 When combined with the detailed 
method of documentation developed by the University of Pennsylvania, the treatment 
methods examined in this study would extend the life of this resource without destroying 
the potential for further study of the resource. 



117 Watkms, Stephanie. "Chemical Watermarking of Paper", Journal of the American Institute for 
Conservation, Volume 29, Number 2, Article 2, 1 990, p. 1 1 7- 1 3 1 . 



121 



Chapter 14 
CONCLUSIONS 

In conclusion, it is the responsibility of a conservator to have a good 
understanding of the cultural resource that they are treating, the mechanisms of 
deterioration affecting this resource, detailed methods for recording these conditions, an 
understanding of treatment methods and a monitoring plan. This study has attempted to 
provide preliminary information necessary to fulfill this responsibility. 

A vast quantity of research has been conducted on the topic of stabilization 
treatments for earthen surface finishes at Mesa Verde National Park. This research has 
led to the development of a detailed condition survey and monitoring procedure. 
Previous testing had been conducted in-situ prior to the outset of this survey. Previous 
field testing involved the use of both acrylic resins and gelatin solutions. This study has 
provided materials testing data that should be considered when selecting an adhesive 
suitable for administering earthen finish conservation treatments. 

The experiments in this study were conducted to clarify the mechanisms of 
deterioration that contribute to a loss of Ancestral Puebloan finishes. The ideal adhesive 
would provide a bond strength between substrate and surface finish that is slightly 
weaker than the cohesive strength of these two adherents. It would sufficiently bond the 
adherents but not seal their pore structure, allowing for good vapor penetration and low 
reflectance. The adhesive formulation would be non-toxic, easy to apply and low cost. 
The ideal treatment would be acceptable to Native American Tribes. It would be flexible 

enough to buffer the environmentally induced differential movement at the junction of 

122 



both adherents. The ideal treatment would also be easily removed, resistant to 
environmental degradation, durable, long lasting, and be suitable to accommodate future 
re treatments. 

The criteria listed above are virtually impossible to satisfy. Yet, each of these 
criteria has been met by at least one of the adhesive formulations tested for this study. 
Therefore, the question becomes not which formulation is the ideal solution for the 
treatment of earthen surface finishes, but which solution is best suited to the specific 
environmental fluctuations that it will be subjected to. 

Based on observations made during accelerated weathering experiments and 
observations made while testing the bond strength of weathered materials, the nature of 
this deterioration causes a continued decrease in the adhesive strength of these particles. 
Thus, the cohesive strength of each layer and the adhesive strength of one layer to the 
next are perpetually weakened by the natural forces of environmentally induced 
deterioration. Since the strength of original materials is not constant, the ideal adhesive 
solution would lose adhesive strength at the same rate as the adherents. Thus, a 
biodegradable adhesive such as gelatin would be preferred. Still, enough information has 
not yet been collected to determine the rate of deterioration. Thus, continued monitoring 
of treated areas is essential for the long-term assessment of these treatments. 

In this case, adhesive films should be viscous enough to provide good adhesion of 
particles of both adherents. However, the penetration of an adhesive should be minimal 
and the wetting of particles not be so thorough that they induce a significant change in 
reflective index. The high viscosity and wetting ability of acrylic emulsions allow them 

to be easily injected with a hypodermic syringe, but also allows them to fill pores and 

123 



create a uniformly smooth surface. This can result in noticeable changes of the visual 
properties of surface finishes. The gelatin solutions, though still indictable, were less 
viscous and easily converted from liquid to gel state. The reduced wettability and 
penetration of gelatin based adhesives made them less prone to these detrimental changes 
in optical quality. 

The ability of an adhesive to absorb stresses that induced the initial damage is 
dependent on many factors. The most prominent physical property affecting this ability 
is elasticity. A sufficiently flexible adhesive film allows the adherents to move 
independently from one another without losing contact with the adhesive film. Visual 
examinations of all four solutions revealed that films of the plasticized gelatin retained 
the most flexibility. As a measure of flexibility, so long as the external plasticizer 
remains entrapped within the gelatin structure, the plasticized gelatin solution is far better 
than that of its acrylic counterparts. Though the acrylic solutions were stronger and 
easier to apply, they did not offer the same elasticity that the externally plasticized gelatin 
solution can provide. The logical result of such treatment would be a very stable, strong, 
and well consolidated area that was treated. However, the same fluctuations of 
environmentally induced expansion and contraction that induced the initial damage 
would still be active. Thus, instead of stabilizing the entire wall, acrylic emulsions would 
theoretically stabilize the areas of initial weakness while the same stresses would induce 
strain-related damage in other portions of the wall when subjected to further 
environmental fluctuations. 

Since the primary environmental factor that induces loss of adhesion is water, 

vapor transmission rate is another significant criteria when selecting an adhesive solution. 

124 



The results of this test showed all formulations to be fairly vapor permeable relative to 
the control. However, the ability of a gelatin and glycerin solution to shrink and swell 
when exposed to humidity present concerns for the use of gelatin based adhesives. In an 
environment with rapid changes in relative humidity, the swelling of gelatin adhesives 
could induce added strain to an already weakened area. However, based on preliminary 
observations at Mesa Verde National Park, the climate is dry enough that this is not a 
substantial concern so long as the gelatin treatments are applied to areas that are not 
actively wetted due to drainage, exposure or capillary action. Thus, the use of gelatin 
adhesive is most useful for the treatment of deterioration that is caused by moisture 
related exposure that is no longer active, but is still subject to further deterioration from 
wind and mechanical abrasion. Furthermore, the retention of water within the structure 
of gelatin adhesives also contributes to the flexibility of the adhesive. 

One potentially detrimental effect of water retention is that it makes a favorable 
environment for biological organisms. However, adding biocides such as sulfur dioxide, 
beta napthol or pentachlorophenoline could limit the damage induced by this threat. Since 
manually removing adhesive treatment formulations is unrealistic, the biodegradable 
gelatin based adhesives have been favored as a naturally reversible treatment. 

Bond strength is the most obvious factor to consider when assessing the feasibility 

of an adhesive solution. For such tests, the bond strength of acrylic solutions was 

stronger than that of the gelatin solutions. However, the 10% solution of plasticized 

gelatin was comparable to 5% solutions of acrylics. Observations made while testing the 

adhesive bond strength of 10% acrylic solutions indicated that their strength was 

oftentimes stronger than the earthen finishes. 

125 



Of the acrylic emulsions tested, Roplex MC-1835 and Roplex E-330 formulations 
performed similarly. However, visual observations revealed that facsimile earthen 
surface finishes treated with MC-1834 withstood accelerated weathering slightly better 
than those treated with E-330. The greater bond strength of the 10% concentrations of 
acrylic indicates that a very small amount of acrylic is needed to establish an adhesive 
bond. 

The cohesive strength of an unrestrained, unplasticized film of gelatin proved to 
be stronger than the earthen plasters it was used to adhere. Hence, gelatin solutions that 
have not been combined with a plasticizing agent are not recommended. The 5% gelatin 
based formulations did not provide enough bond strength to ensure prolonged durability 
of such treatments. However, tests revealed that the 5% MC-1835 provided bond 
strength comparable to that of the 10% plasticized gelatin formulation. Consequently, of 
the four proteinacious formulations tested, the 10% plasticized gelatin solution was the 
more practical option to ensure long-term durability of an adhesive solution. 

In selecting an adhesive for reattachment of earthen surface finishes at Mesa 

Verde National Park, gelatin based formulations were selected in favor of acrylics. This 

decision weighed considerations of bond strength, water vapor permeability, ease of 

application, optical quality, low toxicity, reduced cost and accessibility of materials. The 

testing program described in this study reveals the complexity of issues one must contend 

with when selecting an adhesive formulation for reattachment of earthen surface finishes. 

Preliminary research to predict the effectiveness of an adhesive treatment should include 

both materials and product testing. Research and test results generated by this type of 

research program enable professional architectural conservators to make educated 

126 



decisions regarding the formulation, application and feasibility of individual conservation 
treatments. 



127 



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128 



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Pillsbury, Joanne "Technical Evidence for Temporal Placement: Sculpted Adobe Friezes 
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142 



APPENDIX A: 
List of Soil Samples and Collection Proveniences 



143 



APPENDIX A 


: List of Soil Samples and Collection Proveniences 




Sample Name 


Description of Sample 


Origin of Sample 


Munsell Color 






Interior of Room 24 






Spalled reddish plaster 


(Spruce Tree House 


7.5RY6/4 Light 


STH-2 (r) 


finish 


5MV640:Brisben2001) 


Brown 




Spalled plaster finish 


Interior of Kiva D (Square 






that is predominantly 


Tower 5MV650: Bamett 


7.5YR6/4 Light 


SQT-lO(r) 


reddish 


&Brisben2001) 


Brown 




Spalled finish with 


Interior of Kiva D (Square 


7.5YR8/2 Pinkish 




white wash overlaying 


Tower 5MV650: Bamett 


White overlaying 


SQT-lO(w) 


reddish plaster 


&Brisben2001) 


7.5YR5/4 Brown 






Collected by Kathy Fiero 






Ground caliche 


in the vicinity of Balcony 




SY-1 


fragments 


House 


10YR8/2 White 




Yellowish soil 








currently used for 








Mesa Verde 


Purchased from the Ute 


10YR7/4Very 


SY-2 


stabilization 


Reservation Soil Quarry 


Pale Brown 




Reddish soil currently 


Collected by Kathy Fiero 






used for Mesa Verde 


in vicinity of mesa top 


5YR5/4 Reddish 


SY-3 


stabilization 


helipad 


Brown 






Collected by Rebecca 








Carr in the vicinity of mile 








marker 12, Main Park 




MR-1 


White Kaolinite 


Road 


7.5YR8/1 White 






Collected by Rebecca Can- 








in the vicinity of mile 




MR-4 


White sandstone 


marker 8, Main Park Road 


10YR8/1 White 



144 



APPENDIX B: 
Porosity of Sample Substrates - Total Immersion Test 



145 



APPENDIX B: Porosity of Sample Substrates - Total Immersion Test 



ME VE SANDSTONE 

Pre-Testing Weight (Mo): 



Dry Sample A = 326.5 g 
Dry Sample B = 108.9 g 
Dry Sample C = 291.1 g 



Post-Testing Weight (Md) = 241.8 g: 

Dry Sample A = 326.4 g 
Dry Sample B = 108.7 g 
Dry Sample C = 290.3 g 



Sample Mass (Mn) 



Mass at 5 mm. 
Change in Mass 



Mass at 10 mm. 
Change in Mass 



Mass at 15 mm. 
Change in Mass 



Mass at 30 mm. 
Change in Mass 



Mass at 60 min. 
Change in Mass 



Mass at 790 min. 
Change in Mass 



Mass at 1145 min. 
Change in Mass 



Mass at 1440 min. 
Change in Mass 



Mass at 2880 mm. 
Change in Mass 



Mass at 4320 min. 
Change in Mass 



Mass at 5770 mm. 
Change in Mass 



Mass at 7200 mm. 
Change in Mass 



Mass at 8640 mm. 
Change in Mass 



Mass at 10200 min. 
Change in Mass 



iST-A 



ST-B 



329.0 g 
0.77% 



113.4g 

4.13% 



329.3 g 

0.86% 



114.1 g 

4.78% 



329.4 g 
0.89% 



114.3 g 

4.96% 



330.1 g 
1.10% 



114.4 g 

5.05% 



331.5 g 
1.53% 



114.5 g 

5.14% 



334.5 g 
2.45% 



1 14.5 g 

5.14% 



334.7 g 
2.51% 



114.5 g 
5.14% 



334.7 g 
2.51% 



114.5 g 

5.14% 



334.7 g 
2.51% 



114.5 g 

5.14% 



335.7 g 
2.82% 



115.0g 
5.60% 



336.3 g 
3.00% 



115.4g 
5.97% 



335.6 g 

2.79% 



115.4g 
5.97% 



335.9 g 

2.88% 



115.5 g 

6.06% 



335.9 g 

2.88% 



H5.6g 
6.15% 



IST-C 



295.0 g 
1.34% 



296.4 g 
1.82% 



296.8 g 
1.96% 



297.5 g 

2.20% 



298.7 g 
2.61% 



299.9 g 

3.02% 



300.2 g 
3.13% 



300.1 g 
3.09% 



300.9 g 
3.37% 



300.9 e 
3.37% 



301.4 g 
3.54% 



301.4 g 
3.54% 



301.4 g 
3.54% 



301.4 g 
3.54% 



Hygrostatic weight 1201.8 g 



!67.6g 



180.1 g 



IMean Values (M max & WAC) 

245.8 g 

0.42% 

246.6 g 

1.74% 



246.8 g 
2.07% 



247.3 g 

2.27% 



248.2 g 
2.65% 



249.6 g 
3.23% 



249.8 g 
3.31% 



249.8 g 
3.31% 



250.0 g 
3.39% 



250.5 g 
3.60% 



251.0g 

3.80% 



250.8 g 
3.72% 



250.9 g 
3.76% 



251.0 g 

3.80% 



149.8 g 



146 



APPENDIX B: Porosity of Sample Substrates - Total Immersion Test 



MODERN EXTR UDED E 

Pre-Testing Weight (Mo): 


'RICK (Penn) 

Post-Testing Weight (Md) = 

Dry Sample A = 188.9 g 
Dry Sample B = 185.8 g 
Dry Sample C = 206.4 g 


193.7 g: 




Dry Sample A = 188.9 g 
Dry Sample B= 185.8 g 
Dry Sample C = 206.4 g 




Sample Mass (Mn) 


ST- A 


ST-B 




ST-C 


Mean Values (M 


max & WAC) 


Mass at 5 min. 
Change in Mass 


200.8 g 
6.30% 


197.2 g 
6.14% 




218.8 g 
6.01% 


205.6 g 
6.14% 




Mass at 10 min. 
Change in Mass 


200.8 g 
6.30% 


197.4 g 

6.24% 




218. Sg 
6.01% 


205.7 g 
6.20% 




Mass at 15 min. 
Change in Mass 


200.8 g 
6.30% 


197.4 g 
6.24% 




218.8 g 
6.01% 


205.7 g 
6.20% 




Mass at 30 min. 
Change in Mass 


200.8 g 
6.30% 


197.4 g 
6.24% 




219.0g 
6.30% 


205.7 g 
6.20% 




Mass at 60 min. 
Change in Mass 


201.3 g 
6.56% 


197.8 g 
6.46% 




219.2 g 
6.20% 


206.1 g 
6.40% 




Mass at 940 min. 
Change in Mass 


202.2 g 
7.04% 


199.2 g 

7.21% 




220.2 g 
6.69% 


207.2 g 
6.97% 




Mass at 1 145 min. 
Change in Mass 


202.8 g 
7.36% 


199.3 g 

7.27% 




221.1 g 

7.12% 


207.7 g 
7.23% 




Mass at 1480 min. 
Change in Mass 


202.9 g 
7.41% 


199.3 g 

7.27% 




221.3 g 
7.22% 


207.8 g 
7.28% 




Mass at 2880 min. 
Change in Mass 


204.2 g 
8.10% 


200.9 g 
8.13% 




222.6 g 

7.85% 


209.2 g 
8.02% 




Mass at 4320 min. 
Change in Mass 


204.9 g 
8.47% 


201.1 g 
8.23% 




223.4 g 
8.24% 


209.8 g 

8.31% 




Mass at 5760 min. 
Change in Mass 


205.0 g 
8.52% 


201.5 g 
8.45% 




223.6 g 
8.33% 


210.0 g 

8.42% 




Mass at 7260 min. 
Change in Mass 


205.3 g 
8.68% 


201.6 g 

8.50% 




224.0 g 
8.53% 


210.3 g 

8.57% 




Mass at 8650 min. 
Change in Mass 


205.4 g 
8.73% 


201.7 g 
8.56% 




224.0 g 
8.53% 


210.4 g 
8.60% 




Mass at 10100 min. 
Change in Mass 


205.6 g 
8.84% 


202.0 g 
8.72% 




224.0 g 
8.53% 


210.5 g 
8.69% 




Hygrostatic weight 


1111-2 g 


1109.6 g 




1 121.5 g 


|ll4.1g 





147 



APPENDIX B: Porosity of Sample Substrates - Total Immersion Test 



HISTORIC BRICK (Yellow New Orleans) 

Pre-Testine Weight (Mo): Posr-Testino Weiaht IMH1 = 


= 156.6 2: 




Dry Sample A = 92.9 g 
Dry Sample B = 176.3 g 
Dry Sample C = 201.5 g 




Dry Sample 
Dry Sample 
Dry Sample 


A = 92.6g 
B = 176.0 g 
C = 201.2 g 




Sample Mass (Mn) 


ST-A 


ST-B 


ST-C 


IMean Values (M max & WAC) 


Mass at 5 min. 
Change in Mass 


110.0 g 

18.41% 


209.4 g 
18.77% 


237.2 g 
17.72% 


185.5 g 
18.45% 




Mass at 10 min. 
Change in Mass 


110.1 g 

18.51% 


209.3 g 
18.72% 


237.3 g 
17.77% 


185.6 g 

18.52% 




Mass at 15 min. 
Change in Mass 


110.1 g 
18.51% 


209.5 g 
18.83% 


237.3 g 
17.77% 


185.7 g 
18.53% 




Mass at 30 min. 
Change in Mass 


1 10.2 g 
18.62% 


209.5 g 
18.83% 


237.3 g 
17.77% 


185.7 g 
18.53% 




Mass at 60 min. 
Change in Mass 


110.5 g 
18.95% 


210.4 g 
19.34% 


237.6 g 
17.92% 


186.2 g 
18.88% 




Mass at 620 min. 
Change in Mass 


111.1 g 

19.59% 


211.3 g 

19.85% 


239.2 g 

18.71% 


187.2 g 
19.54% 




Mass at 1 160 min. 
Change in Mass 


111.8 g 

20.34% 


212.5 g 
20.53% 


240.1 g 
19.16% 


188.1 g 
20.14% 




Mass at 1330 min. 
Change in Mass 


111.9g 
20.45% 


212.4 g 
20.48% 


240.1 g 
19.16% 


188.1 g 
20.14% 




Mass at 1480 min. 
Change in Mass 


H2.0g 
20.56% 


212.5 g 
20.53% 


240.4 g 
19.31% 


188.3 g 
20.25% 




Mass at 2880 min. 
Change in Mass 


H2.9g 

21.53% 


214.3 g 
21.55% 


242.4 g 
20.30% 


189.9 g 
21.26% 




Mass at 4320 min. 
Change in Mass 


113. lg 
21.74% 


214.7 g 
21.78% 


243.1 g 
20.65% 


190.3 g 
21.52% 




Mass at 5760 min. 
Change in Mass 


H3.2g 
21.85% 


215.1 g 
22.01% 


243.8 g 
20.99% 


190.7 g 
21.78% 




Mass at 7200 min. 
Change in Mass 


H3.2g 
21.85% 


215.2g 
22.06% 


243.8 g 
20.99% 


190.7 
21.78% 




Hygrostatic weight 


50.1 g 


94.3 g 


106.2 g 


83.5 g 





148 



APPENDIX B: Porosity of Sample Substrates - Total Immersion Test 



HISTORIC BRICK (Red New Orleans) 



Pre-Testing Weight (Mo): 



Dry Sample A = 191.7 g 
Dry Sample B= 139.5 g 
Dry Sample C= 183.4 g 



Post-Testing Weight (Md) = 171.2 v: 
Dry Sample A = 191.4 g 
Dry Sample B= 139.0 g 
Dry Sample C= 183.1 g 



Sample Mass (Mn) 



Mass at 5 min. 
Change in Mass 



Mass at 10 min. 
Change in Mass 



Mass at 1 5 min. 
Change in Mass 



Mass at 30 min. 
Change in Mass 



Mass at 60 min. 
Change in Mass 



Mass at 620 min. 
Change in Mass 



Mass at 1 160 min. 
Change in Mass 



Mass at 1330 min. 
Change in Mass 



Mass at 1480 min. 
Change in Mass 



Mass at 2880 min. 
Change m Mass 



Mass at 4320 min. 
Change in Mass 



Mass at 5760 min. 
Change in Mass 



Mass at 7200 mm. 
Change in Mass 



ST-A 



ST-B 



227.3 g 
18.57% 



165.1 g 

18.35% 



227.3 g 
18.57% 



165.3 g 

18.49% 



227.3 g 
18.57% 



165.4 g 
18.57% 



227.3 g 
18.57% 



165.4 g 
185.66% 



227.3 g 
18.57% 



165.4 g 
18.57% 



228.6 g 
19.25% 



166.4 g 
19.28% 



228.9 g 
19.41% 



166.5 g 
19.35% 



229.2 g 

19.56% 



166.6 g 
19.35% 



229.6 g 
19.77% 



166.9 g 
19.43% 



231.3 g 
20.66% 



168.4 g 
20.72% 



232.4 g 
21.23% 



169.2 g 
21.29% 



234.2 g 
22.17% 



170.4 g 
22.15% 



234.2 g 
22.17% 



170.5 g 
22.22% 



! ST-C 



218.0g 
18.87% 



218.0g 
18.87% 



218.1 g 
18.92% 



218.1 g 
18.92% 



218.1 g 
18.92% 



219.3 g 
19.57% 



220.0 g 
19.96% 



220.2 g 
20.65% 



220.4 g 
20.17% 



221.9 g 

20.99% 



222.7 g 
21.43% 



223.5 g 

21.86% 



223.5 g 
21.86% 



Hygrostatic weight j 1 1 1.9 g 81.5 g 1 106.1 g 



Mean Values (M max & WAC ) 

203.5 g 

18.85% 

203.5 g 

18.89% 



203.6 g 
18.93% 



203.6 g 
18.93% 



203.6 g 
18.93% 



204.8 g 
19.63% 



205.1 g 
19.82% 



205.3 g 
19.94% 



205.6 g 
20.11% 



207.3 g 
21.03% 



208.1 g 
21.55% 



209.4 g 
22.29% 



209.4 g 
22.31% 



99.8g 



149 



APPENDIX B: Porosity of Sample Substrates - Total Immersion Test 



MODERN BRICK 

Pre-Testina Weight (Mo): 


Post-Testins Weight tMd) = 231 .1 «• 




Dry Sample A = 225.9 
Dry Sample B = 236.7 


g 
g 


Dry Sample A - 
Dry Sample B = 


= 225.7 g 
= 236.4 g 


Sample Mass (Mn) 


:ST-A 


ST-B 


Mean Values (M max & WAC) 


Mass at 5 min. 
Change in Mass 


238.2 g 
5.44% 


249.4 g 
5.37% 


243.8 g 
5.52% 




Mass at 10 min. 
Change in Mass 


238.2 g 
5.44% 


249.4 g 
5.37% 


243.8 g 
5.52% 




Mass at 15 min. 
Change in Mass 


238.3 g 
5.48% 


249.4 g 

5.37% 


243.9 g 

5.54% 




Mass at 30 mm. 
Change in Mass 


238.9 g 

5.75% 


249.9 g 

5.56% 


244.4 g 
5.78% 




Mass at 60 min. 
Change in Mass 


239.6 g 
6.06% 


250.8 g 
5.96% 


245.2 g 
6.12% 




Mass at 620 nun. 
Change in Mass 


240.1 g 
6.29% 


251.9g 
6.42% 


246.0 g 

6.47% 




Mass at 1 160 min. 
Change in Mass 


241.4 g 
6.86% 


252.3 g 
6.59% 


246.9 g 

6.84% 




Mass at 1330 min. 
Change in Mass 


241.4 g 
6.86% 


252.5 g 
6.68% 


247.0 g 
6.88% 




Mass at 1480 mm. 
Change in Mass 


241.6 g 
6.95% 


252.8 g 
6.80% 


247.2 g 
6.97% 




Mass at 2880 min. 
Change in Mass 


242.3 g 
7.26% 


253.5 g 
7.10% 


247.9 g 

7.27% 




Mass at 4320 min. 
Change in Mass 


242.6 g 
7.39% 


253.5 g 
7.10% 


248.1 g 
7.33% 




Mass at 5760 min. 
Change in Mass 


242.8 g 
7.48% 


254.0 g 

7.31% 


248.4 g 
7.49% 




Mass at 7200 nun. 
Change in Mass 


242.8 g 
7.48% 


253.9 g 
7.27% 


248.4 g 
7.49% 




Hygrostatic weight 


138.2 g 


j 144.6 g 


[141.4 g 





150 



APPENDIX C: 

Porosity of Sample Substrates - Hygrostatic Weighing Test 



151 



APPENDIX C: Porosity of Sample Substrates - Hygrostatic Weighing Test 





Sandstone 


Modern Extruded 


Historic Brick 


Historic Brick 


Modem Brick 






Brick (P) 


(Yellow) 


(Red) 




Dry Mass (Ml) 


241.8 


193.7 


156.6 


171.2 


231.1 


Immersed Mass (M2) 


149.8 


114.1 


83.5 


99.8 


141.4 


Saturated Mass (M3) 


251.0 


210.5 


190.7 


209.4 


248.4 


Pore Volume 


9.2 


16.8 


34.1 


38.2 


17.3 


(Vp = M3-Ml) 












Apparent Volume 


101.2 


96.4 


107.2 


109.6 


107 


(Va = M3 - M2) 












Real Volume 


92 


79.6 


73.1 


71.4 


89.7 


(Vr = Ml -M2) 












Real Density 


2628.3 


2433.4 


2142.3 


2397.8 


2576.4 


(Pr = [Ml / Vr]x 10 3 ) 












Apparent Density 


2389.3 


2009.3 


1460.8 


1562.0 


2159.8 


(Pa = [Ml/Va]x 10 3 ) 












% Porosity 


9.0% 


17.4% 


31.8% 


34.9% 


16.2% 


([1 -Pa/Pr]x 100) 













35.00% 



30.00% 



25.00% 



20.00% 



15.00% 



10.00% 



5.00% 



0.00% 



Substrate Porosity by Hydrostatic Weighing 




|% Porosity 



Mesa Verde Modern Historic Historic Modern Brick 

Sandstone Extruded Brick Brick (Red) 

Brick (P) (Yellow) 



152 



APPENDIX D: 
Common Additives used in Gelatin Based Formulations 



153 



APPENDIX D: Common Additives used in Gelatin Based Formulations 



Material Specifications 


Description 


Use 


Phenol (monohydroxy benzene) 


A byproduct m the processing of 
acetone. Phenols have a hydroxyl 
(-OH) group bonded to a carbon 
atom that forms part of an aromatic 
ring. Phenols form stronger 
hydrogen bonds than alcohols, are 
water soluble, and acidic, and react 
with formaldehyde. P-phenyl 
phenol is commonly used in gelatin 
solutions. 


Preservative" 8 

(not recommended 
for use on alkaline 
surfaces) 


Chemical C 6 H 6 
Formula 


Molecular 94.1128 
Weight: 


Formaldehyde 


A gas that is usually sold diluted in 
37%-40% water and sold as 
"formalin". Often combined with 
gelatin and gum arable. Hardens 
the surface of gelatin paints when 
sprayed on the surface after cure." 9 
Also used to make gelatin capsules 
for pharmaceutical drugs. 


Hardener, 
preservative, 
decreases water 
solubility 


Chemical CH : 
Formula 


Molecular 30.03 
Weight: 


Glutaraldehyde 


Cross-links with gelatin and gum 
arabic in solution. Commonly used 
to make gelatin capsules for 
pharmaceutical drugs. 


Hardener, 
improves thermal 
resistance, 
decreases water 
solubility 


Chemical C 5 H s O : 
Formula 


Molecular 100.12 
Weight: 


Alum (Potassium chrome alum)' 2u 


A potassium aluminum sulfate salt. 
Used for paper making and leather 
tanning. 


Hardener, 
decreases water 
solubility 


Chemical KA1(S0 4 ) : 12H : 
Formula 


Molecular 788. 13 1 " 
Weight: 



Cassar, JoAnn and Roberta de Angelis. "Glossary. Materials used in 19th and 20th century Plaster 
Architecture. Plaster Architecture Essay, Culture 2000 Programme of the European Union. 
http://www.plasterarc.net/essay/essay/CassarG.html 

Jusko, Don A. "History of Painting Mediums... Glue, Wax Paint, Cera Colla, Mastic, Casem Paint, 
Fresco, Egg, Oil Paint, Acrylic Paint", mauigateway.com. 
http://www.mauigateway.eom/~donjusko/lmediums.htm#l 00,000 B/C 

"° Cassar, JoAnn and Roberta de Angelis. "Glossary. Materials used in 19th and 20th century Plaster 
Architecture. Plaster Architecture Essay, Culture 2000 Programme of the European Union. 
http://www.plasterarc.net/essay/essay/CassarG.html 

Merriam-Webster Inc. "Dictionary", http://www.webster.com 
"" Krompiec, Michal and Luc Patiny. "ChemCalc", Silesian University of Technology, University of 
Lausanne, 5' International Electronic Conference on synthetic Organic Chemistry, ChemExper. 
http://www.chemcalc.org/ 

154 



APPENDIX D: Common Additives used in Gelatin Based Formulations 



Material Specifications 


Description 


Use 


Sorbitol 


A hexahydric alcohol that is used as 
a sweetener in food products 123 , as a 
plasticizer in glue formulations 
and as a softening agent for textiles, 
paper and leather. 125 It occurs 
naturally, but is commercially 
produced by reducing aqueous 
glucose solutions as well. 


Plasticizer 

(Not 

recommended for 
use in arid 
climates) 


Chemical C 6 H !4 „ 
Formula 


Molecular 182.17 
Weight: 


Ammonia 


A colorless, alkaline gas that can be 
condensed into liquid form with 
cold temperature and pressure. " 


Modifies the pH of 

gelatin 

formulations. 12 


Chemical NH 3 
Formula 


Molecular 17.03 
Weight: 


Sulphur Dioxide 


Sulfur dioxide is a gas that is used 
as a solvent in paper production. 
Sulfur is also used as a fungicide 
and insecticide. It is formed by 
burning sulfur. 


Preservative, 
bleaching agent. 


Chemical S0 2 
Formula 


Molecular 64.06 
Weight: 


[Methylene Glycol (DEG) 


Hygroscopic liquid that is used in 
the production of polyester resins 
and polyurethanes. It is also used in 
the production ot paper, glue and 
cellophane. 


Plasticizer 


Chemical C4H10O3 
Formula 


Molecular 106.12 
Weight: 


Iso-Propyl Alcohol (Isopropanol) 


Used as a wetting agent and a 
solvent in many paint formulations 
and as a surfactant in cleaning 
solutions. It also has in medicinal 
and herbicidal (glyphosate) uses. 
Isopropyl is similar to ethyl alcohol 
in solvent properties. 


Wetting agent 


Chemical C 3 H 8 
Formula 


Molecular 60.09 
Weight: 



123 Partos, Lindsey. "FoodNavigator", 2000/2002. http://www.foodnavigator.com/intemet/bestof.asp 

124 Cassar, JoAnn and Roberta de Angelis. "Glossary. Materials used in 19th and 20th century Plaster 
Architecture. Plaster Architecture Essay, Culture 2000 Programme of the European Union. 
http://www.plasterarc.net/essay/essay/CassarG.html 

125 Matt T. Roberts, Don Etherington and Margaret R. Brown. "Bookbinding and the Conservation of 
books: A Dictionary of Descnptive Terminology", Stanford University Libraries, 1994. 
http://palimpsest.stanford.edu/don/don.html 

126 Merriam- Webster Inc. "Dictionary", http://www.webster.com 

127 Cole, Bernard. "Gelatine Food Science", University of Pretona, http://www.gelatin.co.za/gltnl.html 

155 



APPENDIX D: Common Additives used in Gelatin Based Formulations 



Material Specifications 


Description 


Use 


Glycerol (Glycerin) 


A byproduct in the manufacture of 
animal fats and plant oils into soap. 
Glycerin is a hygroscopic tnhednc 
alcohol. Due to its hygroscopicity, 
it is used to retain moisture in 
cosmetics and chemically reacts 
with acetic anhydrides. 


Plasticizer, wetting 
agent, antifreeze 


Chemical C 3 H s (OH) 3 
Formula 


Molecular 92.09 
Weight: 


Propylene glycol 


Used as an antifreeze and solvent. 
Cellulose based glycols are also 
used as plasticizers in glues. 128 


Solvent, wetting 
agent, plasticizer 


Chemical C 3 H 8 02 
Formula 


Molecular 76.10 

Weight: 


Gelatin (Collagen Protein) 


Protein made from denatured 
collagen that has been hydrolized 
by either heat or changes in pH. 
There is variation in the 
composition and pH depending on 
manufacturing processes. Thus, an 
approximate chemical formula and 
molecular weight are given. 12 


Adhesive, 
defoaming agent, 
gelling agent 


Chemical C ]02 H 151 39 N 
Formula 3 , 


Molecular 2435.51 
Weight: 


Beta naphthol 


A monohydnc alcohol within the 
phenol family. It is manufactured 
by fusing naphthalenesulfonic acid 
with caustic soda and is used as 
biocidic preservative in gelatin 
solutions. It is also used in leather 
tanning, antioxidants, and 
antiseptics. 130 


Preservative 


Chemical C 10 H 7 OH 
Formula 


Molecular 144.17 
Weight: 


Pentachlorophenoline 


A crystalline compound that found 
in rabbit skin glue solutions as a 
preservative. Also used as a wood 
preservative. 


Preservative 


Chemical C 6 C1 5 0H 
Formula 


Molecular 266.34 
Weight: 



128 Matt T. Roberts and Don Ethenngton. Bookbinding and the Conservation of books: A Dictionary of 
Descriptive Terminology http://palimpsest.stanford.edu/don/don.html 

129 Matt T. Roberts and Don Ethenngton. Bookbinding and the Conservation of books: A Dictionary of 
Descriptive Terminology http://palimpsest.stanford.edu/don/don.html 

130 Chemical Land 21.com Arokor Holdings Inc. 2000. www.cherrucalland21.com 

156 



APPENDIX E: 

Viscosity of Acrylic and Gelatin Adhesive Solutions 



157 



APPENDIX E: Viscosity of Acrylic and Gelatin Adhesive Solutions 



Concentration 
of Solution 


Cup 

Size 


Temperature 
(Celsius) 


Time Time 
(Seconds) (Seconds) 


Time 
(Seconds) 


MEAN 
VISCOSITY 


5% GW 


#1 


25 


35.3 


36.1 


32.8 


34.7 


5% GW 


#1 


48 


31.5 


31.6 


31.4 


31.5 


5% GW 


#2 


25 


16.1 


15.6 


15.8 


15.8 


5% GW 


#3 


25 


7.6 


8.2 


8.1 


8.0 


10% GW 


#1 


25 


50.8 


56.1 


52.3 


53.1 


10% GW 


#1 


51 


35.2 


35.4 


35.2 


35.3 


10% GW 


#1 


61 


33.9 


34.3 


34.1 


34.1 


10% GW 


#2 


25 


28.0 


23.9 


26.7 


26.2 


10%GW 


#3 


29 


8.3 


8.4 


8.3 


8.3 


5% GG 


#1 


25 


35.8 


40.4 


38.7 


38.3 


5%GG 


#1 


56 


30.5 


30.7 


31.0 


30.7 


5%GG 


#1 


70 


30.8 


31.2 


31.2 


31.1 


5% GG 


#2 


25 


24.8 


27.4 


27.6 


26.6 


10% GG 


#1 


27 


45.5 


44.8 


46.2 


45.5 


10%GG 


#1 


47 


33.3 


37.4 


37.4 


36.0 


10%GG 


#1 


66 


34.5 


34.4 


34.6 


34.5 


10% GG 


#2 


25 


23.9 


24.6 


25.3 


24.6 


10% GG 


#3 


25 


16.3 


15.7 


17.2 


16.4 


5% MC 


#1 


25 


28.5 


28.6 


28.8 


28.6 


5% MC 


#2 


25 


13.8 


14.1 


13.9 


13.9 


10% MC 


#1 


25 


28.6 


28.5 


28.5 


28.5 


10% MC 


#2 


25 


13.8 


12.9 


13.6 


13.4 


5%E 


#1 


25 


28.7 


28.8 


29.0 


28.8 


5%E 


#2 


25 


13.7 


13.9 


13.8 


13.8 


10% E 


#1 


25 


29.4 


28.9 


29.1 


29.1 


10% E 


#2 


25 


13.8 


13.9 


13.7 


13.8 



158 



APPENDIX F: 
Shrinkage Cracks formed on Reproduction Surface Finishes 



159 



APPENDIX F: Shrinkage Cracks formed on Reproduction Surface Finishes 



Sample # 


Substrate 


Treatment Solution 


Temperature 
(Celsius) 


Observations 
(24 hours) 


RBP-1 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


25 


Micro-Cracks 


RBP-2 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


25 


Micro-Cracks 


RBP-3 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


25 


Micro-Cracks 


RBP-4 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


25 


No Cracks; 
still in gel 
state on top of 
surface 


RBP-5 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


25 


No Cracks; 
still in gel 
state on top of 
surface 


RBP-6 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


25 


No Cracks; 
still in gel 
state on top of 
surface 


RBP-7 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


25 


Micro-Cracks 


RBP-8 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


25 


No Cracks 


RBP-9 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


25 


Micro-cracks 


RBP-10 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


25 


Detached 


RBP-1 1 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


25 


Detached 


RBP-12 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


25 


Detached 


RBP-1 3 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


30 


Micro-Cracks 



160 



APPENDIX F: Shrinkage Cracks formed on Reproduction Surface Finishes 


Sample # 


Substrate 


Treatment Solution 


Temperature 
(Celsius) 


Observations 
(24 hours) 


RBP-14 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


30 


Micro-Cracks 


RBP-15 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


30 


Micro-Cracks 


RBP-16 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


30 


No Cracks 


RBP-17 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


30 


No Cracks 


RBP-18 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


30 


Macro-Cracks 


RBP-19 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


30 


Micro-Cracks 


RBP-20 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


30 


Micro-Cracks 


RBP-21 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


30 


Micro-Cracks 


RBP-22 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


30 


Micro-Cracks 


RBP-23 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


30 


Macro-Cracks 


RBP-24 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


30 


Macro-Cracks 


WW-1 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin 
in Water 


25 


Micro-Cracks 


WW-2 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin 
in Water 


25 


Micro-Cracks 


WW-3 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin 
in Water 


25 


Micro-Cracks 


WW-4 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


25 


No Cracks; 
still in gel 
state on top of 
surface 



161 



APPENDIX F: Shrinkage Cracks formed on Reproduction Surface Finishes 



Sample # 


Substrate 


Treatment Solution 1 Temperature 
1 (Celsius) 


Observations 
(24 hours) 


WW-5 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


25 


No Cracks; 
still in gel 
state on top of 
surface 


WW-6 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


25 


No Cracks; 
still in gel 
state on top of 
surface 


WW-7 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


25 


Micro-Cracks 


WW-8 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


25 


Micro-Cracks 


WW-9 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


25 


No Cracks 


WW- 10 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


25 


Detached 


WW- 11 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


25 


Detached 


WW- 12 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


25 


Detached 


WW- 13 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin 
in Water 


30 


Micro-Cracks 


WW- 14 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin 
in Water 


30 


Micro-Cracks 


WW- 15 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin 
in Water 


30 


Micro-Cracks 


WW- 16 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


30 


No Cracks 


WW- 17 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


30 


No Cracks 


WW- 18 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


30 


No Cracks 


WW- 19 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


30 


No Cracks 


WW-20 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


30 


Micro-Cracks 


WW-21 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


30 


Micro-Cracks 


WW-22 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


30 


Detached to 

underlying 

layer 


WW-23 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


30 


Detached 



162 



APPENDIX F: Shrinkage Cracks formed on Reproduction Surface Finishes 



Sample # 


Substrate 


Treatment Solution 


Temperature 
(Celsius) 


Observations 
(24 hours) 


WW-24 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


30 


Detached 


RBP-25 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


40 


No Cracks 


RBP-26 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


40 


Micro-Cracks 


RBP-27 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


40 


Micro-Cracks 


RBP-28 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


40 


Micro-Cracks 


RBP-29 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


40 


Micro-Cracks 


RBP-30 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


40 


Micro-Cracks 


RBP-31 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


40 


Micro-Cracks 


RBP-32 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


40 


No Cracks 


RBP-33 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


40 


Micro-Cracks 


RBP-34 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


40 


Micro-Cracks 


RBP-35 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


40 


Micro-Cracks 


RBP-36 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


40 


Micro-Cracks 


RBP-37 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


20 


No Cracks 



163 



APPENDIX F: Shrinkage Cracks formed on Reproduction Surface Finishes 


Sample # 


Substrate 


Treatment Solution 


Temperature 
(Celsius) 


Observations 
(24 hours) 


RBP-38 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


20 


No Cracks 


RBP-39 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin 
in Water 


20 


No Cracks 


RBP-40 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


20 


No Cracks 


RBP-41 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


20 


No Cracks 


RBP-42 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin 
in Water 


20 


No cracks 


RBP-43 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


20 


Detached 


RBP-44 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


20 


Detached 


RBP-45 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


20 


Detached 


RBP-46 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


20 


Detached 


RBP-47 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


20 


Detached 


RBP-48 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


20 


Detached 


WW-25 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


50 


No Cracks 


WW-26 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


20 


Micro-Cracks 


WW-27 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


19 


Macro-Cracks 


WW-28 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


19 


Macro-Cracks 


WW-29 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin 
in Water 


19 


Macro-Cracks 



164 



APPENDIX G: 

Relative Absorption for Reproduction Surface Finishes 



165 



APPENDIX G: Relative Absorption for Reproduction Surface Finishes 



Sample 



Reddish Brown Plaster - 1 



Reddish Brown Plaster - 2 



Reddish Brown Plaster - 3 



White Sandstone Wash - 1 



White Sandstone Wash - 2 



White Sandstone Wash - 3 



Reddish Brown Wash -1 



Reddish Brown Wash 



Reddish Brown wash - 3 



Reddish Brown Plaster covered bv White Wash -1 



Reddish Brown Plaster covered by White Wash - 2 



Reddish Brown Plaster covered by White Wash - 3 



Reddish Brown Plaster covered by Reddish Brown Wash - 1 



Reddish Brown Plaster covered by Reddish Brown Wash - 2 



Absorption 
Time (UW) 



0.5 



0.4 



0.5 



0.7 



0.5 



0.4 



0.5 



0.3 



0.4 



1.4 



0.9 



1.0 



0.4 



Reddish Brown Plaster covered bv Reddish Brown Wash - 3 



Reddish Brown Plaster and Caliche White Wash Treated with 
10%GW- 1 



Reddish Brown Plaster and Caliche White Wash Treated with 
10%GW-2 



Reddish Brown Plaster and Caliche White Wash Treated with 
10%GW-3 



Reddish Brown Plaster and Caliche White Wash Treated with 
Water - 1 



Reddish Brown Plaster and Caliche White Wash Treated with 
Water - 2 



Reddish Brown Plaster and Caliche White Wash Treated with 
Water - 3 



Reddish Brown Plaster and Caliche White Wash Treated with 
5%GW - 1 



0.2 



0.2 



1.5 



1.6 



1.3 



1.4 



0.9 



1.2 



Reddish Brown Plaster and Caliche White Wash Treated with 
5%GW - 2 



Reddish Brown Plaster and Caliche White Wash Treated with 
5%GW - 3 



Reddish Brown Plaster and Caliche White Wash Treated with 
5%GG - 1 



Reddish Brown Plaster and Caliche White Wash Treated with 
5%GG- 2 



Reddish Brown Plaster and Caliche White Wash Treated with 
5%GG - 3 



Reddish Brown Plaster and Caliche White Wash Treated with 
10%GG- 1 



Reddish Brown Plaster and Caliche White Wash Treated with 
10%GG-2 



Reddish Brown Plaster and Caliche White Wash Treated with 
10%GG-3 



1.1 



0.7 



0.7 



1.4 



0.8 



1.3 



1.0 



1.6 



1.4 



Absorption 
Time (W) 



1.3 



1.4 



1.7 



1.5 



1.3 



1.4 



1.0 



1.0 



1.1 



1.5 



1.4 



1.5 



1.9 



1.7 



5.6 



166 



APPENDIX H: 
Cohesive Shrinkage for Gelatin Based Adhesive Formulations 



167 



APPENDIX H: Cohesive Shrinkage for Gelatin Based Adhesive Formulations 



Sample # 


Substrate 


Treatment Solution 


Temperature 
(Celsius) 


Observations 

(24 hours) 


RBP-1 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


25 


Micro-Cracks 


RBP-2 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


25 


Micro-Cracks 


RBP-3 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


25 


Micro-Cracks 


RBP-4 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycenn in 
Water 


25 


No Cracks; 
still in gel 
state on top 
of surface 


RBP-5 


Reddish 
Brown Plaster 
(60:40) 


1 0% Gelatin with Glycerin in 
Water 


25 


No Cracks; 
still in gel 
state on top 
of surface 


RBP-6 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin in 
Water 


25 


No Cracks; 
still in gel 
state on top 
of surface 


RBP-7 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


25 


Micro-Cracks 


RBP-8 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


25 


No Cracks 


RBP-9 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


25 


Micro-cracks 


RBP-10 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


25 


Detached 


RBP-1 1 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


25 


Detached 


RBP-12 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


25 


Detached 


RBP-13 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


30 


Micro-Cracks 



168 



APPENDIX H: Cohesive Shrinkage for Gelatin Based Adhesive Formulations 



Sample # 


Substrate 


Treatment Solution 


Temperature 
(Celsius) 


Observations 
(24 hours) 


RBP-14 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


30 


Micro-Cracks 


RBP-15 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


30 


Micro-Cracks 


RBP-16 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin in 
Water 


30 


No Cracks 


RBP-17 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin in 
Water 


30 


No Cracks 


RBP-18 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin in 
Water 


30 


Macro- 
Cracks 


RBP-19 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


30 


Micro-Cracks 


RBP-20 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


30 


Micro-Cracks 


RBP-21 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


30 


Micro-Cracks 


RBP-22 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


30 


Micro-Cracks 


RBP-23 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


30 


Macro- 
Cracks 


RBP-24 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


30 


Macro- 
Cracks 


WW-1 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin in 
Water 


25 


Micro-Cracks 


WW-2 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin in 
Water 


25 


Micro-Cracks 


WW-3 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin in 
Water 


25 


Micro-Cracks 



169 



APPENDIX H: Cohesive Shrinkage for Gelatin Based Adhesive Formulations 



Sample # 


Substrate 


Treatment Solution 


Temperature 
(Celsius) 


Observations 
(24 hours) 


WW-4 
WW-5 


White (SY-1) 
Wash (10:90) 

White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 

10% Gelatin with Glycerin in 
Water 


25 
25 


No Cracks; 
still in gel 
state on top 
of surface 
No Cracks; 
still in gel 
state on top 
of surface 


WW-6 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


25 


No Cracks; 
still in gel 
state on top 
of surface 


WW-7 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


25 


Micro-Cracks 


WW-8 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


25 


Micro-Cracks 


WW-9 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


25 


No Cracks 


WW- 10 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


25 


Detached 


WW- 11 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


25 


Detached 


WW- 12 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


25 


Detached 


WW-13 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin in 
Water 


30 


Micro-Cracks 


WW- 14 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin in 
Water 


30 


Micro-Cracks 


WW- 15 


White (SY-1) 
Wash (10:90) 


5% Gelatin with Glycerin in 
Water 


30 


Micro-Cracks 


WW-16 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


30 


No Cracks 


WW- 17 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


30 


No Cracks 


WW-18 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


30 


No Cracks 


WW- 19 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


30 


No Cracks 


WW-20 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


30 


Micro-Cracks 


WW-21 


White (SY-1) 
Wash (10:90) 


5% Gelatin in Water 


30 


Micro-Cracks 



170 



APPENDIX H: Cohesive Shrinkage for Gelatin Based Adhesive Formulations 



Sample # 


Substrate 


Treatment Solution 


Temperature 

(Celsius) 


Observations 
(24 hours) 


WW-22 


White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 


30 


Detached to 

underlying 

laver 


WW-23 
WW-24 


White (SY-1) 
Wash (10:90) 
White (SY-1) 
Wash (10:90) 


10% Gelatin in Water 
10% Gelatin in Water 


30 
30 


Detached 
Detached 


RBP-25 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


40 


No Cracks 


RBP-26 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


40 


Micro-Cracks 


RBP-27 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycenn in 
Water 


40 


Micro-Cracks 


RBP-28 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycenn in 
Water 


40 


Micro-Cracks 


RBP-29 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycenn in 
Water 


40 


Micro-Cracks 


RBP-30 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycenn in 
Water 


40 


Micro-Cracks 


REP-31 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


40 


Micro-Cracks 


RBP-32 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


40 


No Cracks 


RBP-33 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


40 


Micro-Cracks 


RBP-34 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


40 


Micro-Cracks 


RBP-35 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


40 


Micro-Cracks 



171 



APPENDIX H: Cohesive Shrinkage for Gelatin Based Adhesive Formulations 



Sample # 


Substrate 


Treatment Solution 


Temperature 

(Celsius) 


Observations 
(24 hours) 


RBP-36 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


40 


Micro-Cracks 


RBP-37 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


20 


No Cracks 


RBP-38 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


20 


No Cracks 


RBP-39 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin with Glycerin in 
Water 


20 


No Cracks 


RBP-40 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin in 
Water 


20 


No Cracks 


RBP-41 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin in 
Water 


20 


No Cracks 


RBP-42 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin with Glycerin in 
Water 


20 


No cracks 


RBP-43 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


20 


Detached 


RBP-44 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


20 


Detached 


RBP-45 


Reddish 
Brown Plaster 
(60:40) 


5% Gelatin in Water 


20 


Detached 


RBP-46 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


20 


Detached 


RBP-47 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


20 


Detached 


RBP-48 


Reddish 
Brown Plaster 
(60:40) 


10% Gelatin in Water 


20 


Detached 


WW-25 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


50 


No Cracks 


WW-26 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


20 


Micro-Cracks 



172 



APPENDIX H: Cohesive Shrinkage for Gelatin Based Adhesive Formulations 



Sample # 


Substrate 


Treatment Solution 


Temperature 

(Celsius) 


Observations 
(24 hours) 


WW-27 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


19 


Macro- 
Cracks 


WW-28 


White (SY-1) 
Wash (10:90) 


1 0% Gelatin with Glycerin in 
Water 


19 


Macro- 
Cracks 


WW-29 


White (SY-1) 
Wash (10:90) 


10% Gelatin with Glycerin in 
Water 


19 


Macro- 
Cracks 



173 



APPENDIX I: 

Adhesive Bond Strength of Treated Samples 



174 



APPENDIX I: Adhesive Bond Strength of Treated Samples 



Sample 


Adhesive 


Notes 


Bond 

Strength 

(lbs.) 


A 


Water 


Force Meter Test - break located at 
interface between substrate and plaster 


1.46 


J 


Water 


Force Meter Test - break located at 
interface between substrate and plaster 


1.90 


S 


Water 


Force Meter Test - break located at 
interface between substrate and plaster 


2.35 


w 


5% Gelatin in 
Water 


Force Meter Test - break located at 
interface between substrate and plaster 


0.10 


N 


5% Gelatin in 
Water 


Force Meter Test - break located at 
interface between substrate and plaster 


0.04 


E 


5% Gelatin in 
Water 


Instron test - break located at the 
interface between substrate and plaster. 
Scale could not capture exact moment of 
break. 


NA 


F 


10% Gelatin in 
Water 


Instron test - break located within plaster 
layer, above the interface between 
substrate and plaster. Crumbled fracture. 


430 


P 


10% Gelatin in 
Water 


Instron test - break located within plaster 
layer, above the interface between 
substrate and plaster. Crumbled fracture. 


420 


X 


10% Gelatin in 
Water 


Instron test - break located within plaster 
layer, above the interface between 
substrate and plaster. Crumbled fracture. 


442 


M 


5% Gelatin & 10% 
Glycerin in Water 


Force Meter Test - break located at 
interface between substrate and plaster 


0.07 


D 


5% Gelatin & 10% 
Glycerin in Water 


Force Meter Test - break located at 
interface between substrate and plaster 


0.43 


V 


5% Gelatin & 10% 
Glycerin in Water 


Force Meter Test - break located at 
interface between substrate and plaster 


0.12 


G 


10% Gelatin & 
10% Glycerin in 
Water 


Instron test - break located at the 
interface between substrate and plaster 
Lost failure point. Crumbled fracture. 


286 


Z 


10% Gelatin & 
1 0%Glycerin in 
Water 


Instron test - half of the break was 
located at the interface between substrate 
and plaster while the other half crumbled 
but did not fully detach from the 
substrate. 


125 



175 



APPENDIX I: Adhesive Bond Strength of Treated Samples 




Sample 


Adhesive 


Notes 


Bond 

Strength 

(lbs.) 





10% Gelatin & 
10% Glycerin in 
Water 


Instron test - half of the sample exhibited 
a break located within plaster layer, 
while the other half experienced a break 
at the interface between substrate and 
plaster. Crumble fracture. 


186 


H 


5% Rhoplex E-330 
in Water 


Instron test - half of the sample exhibited 
a break located within plaster layer, 
while the other half experienced a break 
at the interface between substrate and 
plaster. 


72 


Q 


5% Rhoplex E-330 
in Water 


Instron test - break located at interface 
between substrate and plaster. 


60 


Y 


5% Rhoplex E-330 
in Water 


Instron test - break located at the 
interface between substrate and plaster. 


55 


I 


10% Rhoplex E- 
330 in Water 


Instron test - break located at the 
interface between substrate and plaster. 


46 


R 


10% Rhoplex E- 
330 in Water 


Instron test - break located at the 
interface between substrate and plaster. 


138 


AB 


10% Rhoplex E- 
330 in Water 


Instron test - break located at the 
interface between substrate and plaster. 


100 


B 


5% Rhoplex MC- 
1834 in Water 


Instron test - half of the sample exhibited 
a break located within plaster layer, 
while the other half experienced a break 
at the interface between substrate and 
plaster. 


261 


T 


5% Rhoplex MC- 
1834 in Water 


Instron test - break located within plaster 
layer, at the interface between substrate 
and plaster. 


281 


L 


5% Rhoplex MC- 
1834 in Water 


Instron test - break located at the 
interface between substrate and plaster. 


55 


C 


10% Rhoplex MC- 
1834 in Water 


Instron test - break located within plaster 
layer, above the interface between 
substrate and plaster. Crumbled fracture. 


621 


K 


10% Rhoplex MC- 
1834 in Water 


Instron test - break located at the 
interface between substrate and plaster. 


641 


U 


10% Rhoplex MC- 
1 834 in Water 


Instron test - break located within plaster 
layer, above the interface between 
substrate and plaster. Crumbled fracture. 


481 



176 



APPENDIX I: Adhesive Bond Strength of Treated Samples 



GravimetricComparison of Water Vapor Transmission for 10% Formulations 



40 - 


Water Vapor Transmission 


u> 35 - 
o 

-i 30 - 

Sg25 
! 1 20- 

« 3 15- 

| 10 - 

RJ c 
W ° 

i 
























































































Control 10% GW 5% GG 10% GG 10% MC 10% E 
Sample Formulations 



Comparison of Mean Water Vapor Transmission Rates 



14 


Vteter Vapor Transmission Rate 




12 
10 

8- 
6- 
4 
2 
n - 




































□ Water Vapor 
Transmission Rate 








Control 10% 5%GG 10% 10% 10% E 
GW GG MC 





177 



APPENDIX J: 
Water Vapor Transmission Rate of Treated Samples 



178 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Sample Number 


Control- 1 


Control-2 


Control-3 


10% 
GW-1 


10% 
GW-2 


10% 
GW-3 


36 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


75% 


75% 


75% 


75% 


75% 


75% 


Mass (g) 


279.3 


283.1 


280.0 


285.4 


290.4 


280.6 


60 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


278.7 


281.3 


278.2 


283.2 


287.5 


278.8 


84 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


48% 


48% 


48% 


48% 


48% 


48% 


Mass (g) 


277.0 


278.3 


276.6 


281.9 


286.8 


276.8 


108 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


50% 


50% 


50% 


50% 


50% 


50% 


Mass (g) 


275.5 


276.0 


274.9 


281.0 


285.1 


275.4 


132 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


273.2 


274.2 


272.0 


279.4 


283.3 


273.5 


156 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


65% 


65% 


65% 


65% 


65% 


65% 


Mass (g) 


272.2 


270.9 


270.5 


278.4 


282.1 


272.8 


180 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


270.3 


268.8 


268.5 


276.5 


280.4 


271.1 


205 hours 


Temp 


58 


58 


58 


68 


68 


68 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


1 


Mass (g) 


268.8 


267.1 


266.8 


275.1 


278.9 


269.7 



179 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Sample Number 


Control- 1 


Control-2 


Control-3 


10% 
GW-1 


10% 
GW-2 


10% 
GW-3 


229 hours 


Temp 
RH 


68 
50% 


68 

50% 


68 
50% 


68 
50% 


68 
50% 


68 

50% 


Mass (g) 


265.6 


263.6 


263.7 


273.8 


277.6 


268.3 


257 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


56% 


56% 


56% 


56% 


56% 


56% 


Mass (g) 


263.8 


260.0 


261.7 


272.4 


276.0 


267.2 


421 hours 


Temp 


66 


66 


66 


66 


66 


66 


RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


255.5 


252.6 


254.3 


265.3 


269.4 


259.9 


448 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


254 


250.9 


252.4 


263.9 


267.9 


258.6 


472 hours 


Temp 


71 


71 


71 


71 


71 


71 


%RH 


41% 


41% 


41% 


41% 


41% 


41% 


Mass (g) 


252.4 


250.6 


251.1 


262.4 


266.7 


257.3 


500 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


251 


248 


249.7 


261.1 


265.3 


255.9 


520 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


39% 


39% 


39% 


39% 


39% 


39% 


Mass (g) 


249.8 


246.8 


248.5 


260 


264.4 


254.7 


548 hours 


Temp 


58 


68 


68 


58 


58 


58 


5 /oRH 


42% 


42% 


42% 


42% 


42% 


42% 




Vlass(g) 248.2 


245.4 


247 


258.9 


263.1 


253.3 



180 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Sample Number 


Control- 1 


Control-2 


Control-3 


10% GW- 
1 


10% GW- 

2 


10% GW- 

3 


572 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


247 


244 


245.9 


257.6 


261.8 


252.1 



Sample Number 


5% 
GG-1 


5% 
GG-2 


5% 
GG-3 


10% 
GG-1 


10% 
GG-2 


10% 
GG-3 


36 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


75% 


75% 


75% 


75% 


75% 


75% 


Mass (g) 


285.1 


290.4 


286.6 


288.6 


278.4 


291.0 


60 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


283.2 


288.6 


284.9 


287.0 


276.6 


289.6 


84 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


48% 


48% 


48% 


48% 


48% 


48% 


Mass (g) 


281.9 


286.7 


283.5 


285.7 


274.8 


288.2 


108 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


50% 


50% 


50% 


50% 


50% 


50% 


Mass (g) 


280.5 


284.9 


282.4 


284.3 


273.0 


286.8 


132 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


279.0 


283.0 


280.5 


282.9 


271.5 


285.4 


156 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


65% 


65% 


65% 


65% 


65% 


65% 


Mass (g) 


278.1 


281.4 


280.0 


282.2 


270.1 


284.7 



181 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Sample Number 


5% 
GG-1 


5% 
GG-2 


5% 
GG-3 


10% 
GG-1 


10% 
GG-2 


10% 
GG-3 


180 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


276.6 


279.9 


278.2 


280.5 


268.4 


283.1 


205 hours 


Temp 


68 


68 


68 


68 


68 


68 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


275.0 


277.9 


276.8 


279.3 


266.9 


281.7 


229 hours 


Temp 


68 


68 


68 


68 


68 


68 


RH 


50% 


50% 


50% 


50% 


50% 


50% 


Mass (g) 


273.4 


275.7 


275.7 


278.1 


265.4 


280.4 


257 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


56% 


56% 


56% 


56% 


56% 


56% 


Mass (g) 


272.5 


273.6 


274.3 


276.7 


262.0 


279.5 


421 hours 


Temp 


66 


66 


66 


66 


66 


66 


RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


266 


267.4 


267.8 


270.2 


257.6 


272.6 


448 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


264.6 


266.1 


266.5 


269 


256.2 


271.3 


472 hours 


Temp 


71 


71 


71 


71 


71 


71 


%RH 


41% 


41% 


41% 


41% 


41% 


41% 


Mass (g) 


263.4 


264.8 


265.7 


267.7 


255 


270.2 


500 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


262 


263.6 


264.1 


266.4 


253.7 


269 



182 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Sample Nu 


mber 


5% 
GG-1 


5% 
GG-2 


5% 
GG-3 


10% 
GG-1 


10% 
GG-2 


10% 
GG-3 


520 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


39% 


39% 


39% 


39% 


39% 


39% 


Mass (g) 


261.1 


262.6 


263.1 


265.5 


252.8 


268 


548 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


260 


261.4 


261.9 


264.2 


251.5 


266.9 


572 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


258.8 


260.3 


261.0 


263.1 


250.6 


265.7 



Sample Number 


10% 
MC-1 


10% 
MC-2 


10% 
MC-3 


10% 
E-l 


10% 
E-2 


10% 
E-3 


36 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


75% 


75% 


75% 


75% 


75% 


75% 


Mass (g) 


294.0 


301.0 


309.0 


301.0 


308.0 


304.8 


60 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


290.7 


298.8 


307.4 


299.5 


307.9 


302.9 


84 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


48% 


48% 


48% 


48% 


48% 


48% 


Mass (g) 


289.6 


297.0 


306.1 


298.3 


306.5 


300.6 


108 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


50% 


50% 


50% 


50% 


50% 


50% 


Mass (g) 


288.1 


294.9 


304.7 


296.9 


304.9 


300.2 



183 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Sample Number 


10% 
MC-1 


10% 
MC-2 


10% 
MC-3 


10% 
E-l 


10% 

E-2 


10% 
E-3 


132 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


286.4 


293.3 


303.3 


295.3 


303.2 


298.6 


156 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


65% 


65% 


65% 


65% 


65% 


65% 


Mass (g) 


285.3 


291.8 


302.6 


294.5 


301.7 


297.7 


180 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


283.4 


290.0 


300.8 


292.6 


300.0 


295.9 


205 hours 


Temp 


68 


68 


68 


68 


68 


68 


RH 


35% 


35% 


35% 


35% 


35% 


35% 


Mass (g) 


282.0 


288.6 


299.4 


291.3 


298.7 


294.4 


229 hours 


Temp 


68 


68 


68 


68 


68 


68 


RH 


50% 


50% 


50% 


50% 


50% 


50% 


Mass (g) 


273.7 


286.8 


298.1 


290.0 


297.4 


293.3 


257 hours 


Temp 


70 


70 


70 


70 


70 


70 


RH 


56% 


56% 


56% 


56% 


56% 


56% 


Mass (g) 


273.1 


285.3 


296.8 


288.8 


295.9 


291.9 


421 hours 


Temp 


66 


66 


66 


66 


66 


66 


RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


271.9 


278.6 


290.2 


282 


289.8 


285.3 


448 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


270.5 


277.1 


288.9 


280.7 


288.4 


283.8 



184 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Sample Number 


10% 
MC-1 


10% 
MC-2 


10% 
MC-3 


10% 
E-l 


10% 
E-2 


10% 
E-3 


472 hours 


Temp 


71 


71 


71 


71 


71 


71 


%RH 


41% 


41% 


41% 


41% 


41% 


41% 


Mass (g) 


269.4 


275.8 


287.5 


279.6 


287.2 


282.6 


500 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


38% 


38% 


38% 


38% 


38% 


38% 


Mass (g) 


268 


274.5 


286.2 


278.2 


285.9 


281.1 


520 hours 


Temp 


70 


70 


70 


70 


70 


70 


%RH 


39% 


39% 


39% 


39% 


39% 


39% 


Mass (g) 


267.1 


273.5 


285.1 


277.2 


285 


280.2 


548 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


265.7 


272.1 


283.9 


275.8 


283.7 


279.1 


572 hours 


Temp 


68 


68 


68 


68 


68 


68 


%RH 


42% 


42% 


42% 


42% 


42% 


42% 


Mass (g) 


264.6 


270.9 


282.8 


274.6 


282.7 


278 



185 



APPENDIX J: Water Vapor Transmission Rate of Treated Samples 



Summary of Gravimetric Loss by Water Vapor Transmission 



Sample Solution 


Container 

Weight 

(grams) 


Sample 
Weight 
(grams) 


Original 

Weight 

(grams) 


Control- 1 


5.4 


98.2 


281.6 


Control-2 


4.8 


99.2 


285.3 


Control-3 


5.6 


94.6 


281.0 


1 0% G W- 1 ( 1 0% Gelatin in water) 


5.5 


100.6 


284.6 


10%GW-2 (10% Gelatin in water) 


5.4 


109.6 


292.1 


10%GW-3 (10% Gelatin in water) 


5.6 


93.8 


280.9 


5% GG- 1 (5% Gelatin with 1 0% Glycerin in water) 


5.5 


101.4 


284.4 


5% GG-2 (5% Gelatin with 1 0% Glycerin in water) 


5.2 


108.4 


292.0 


5% GG-3 (5% Gelatin with 1 0% Glycerin in water) 


5.0 105.9 


287.5 


10% GG-1 (10% Gelatin with 10% Glycerin in water) 5.0 


105.8 


284.3 


10% GG-2 (10% Gelatin with 10% Glycerin in water) 5.1 


99.4 


279.8 


10% GG-3 (10% Gelatin with 10% Glycerin in water) 5.4 


107.0 


291.7 


10%MC-1 (10%MC-1834inwater) 


5.5 


121.0 


298.1 


1 0% MC-2 ( 1 0% MC- 1 834 in water) 


5.1 


120.7 


302.7 


1 0% MC-3 ( 1 0% MC- 1 834 in water) 


5.3 


124.8 


309.7 


10% E-l (10% E-330 in water) 


5.5 


117.6 


299.5 


1 0% E-2 ( 1 0% E-330 in water) 


5.6 


123.6 


310.7 


10% E-3 (10% E-330 in water) 


5.2 


121.6 


305.7 



186 



APPENDIX K: 

Accelerated Weathering - Preliminary Testing 



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Substrate: Modern Extruded Brick 

Surface Finishes: Reddish Brown Plaster with a White Wash 

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Surface Finishes: Reddish Brown Plaster with a White Wash 

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Surface Finishes: Reddish Brown Plaster with a Reddish Brown Wash 
Weathered Samples - Treated 



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APPENDIX O: 

Substrate: Modern Extruded Brick (Penn) 

Surface Finishes: Reddish Brown Plaster with a Reddish Brown Wash 

Weathered Samples - Digital Condition Maps 







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APPENDIX P: 
Rohm and Haas Product Performance Specification Sheets 



ISO 




I N 



RHOPLEX® E-330 

Cement Mortar Modifier 



Introduction 

Performa nee Adva ntages 

Phvsical & Chemical Properties 

Suggested Starting Formulations for RHOPLEX® E-o^O 

FormulaWDJLujde.w.ith^HpPLEX®_E-330 

Variables Affecting Cement Mortor Properties Using RHOPLEX 5 

Safe Handling Information 



RHOPLEX® E-330 

Cement Mortar Modifier 



RHOPLEX® E-330 is a water dispersion of an acrylic polymer specifically designed for 
modifying Portland cement compos.tions. Important application areas include 
patching and resurfacing, floor underlayments, terrazzo flooring spray and fill coats, 
precat architectural building panels, stucco, industrial cement floors, and highway 
and br dqe deck repair. Additional information on cement modifiers is available in the 
inni azotes for RHOPLEX® MC-76, RHOPLEX® MC-1834, and DRYCRYL® DP-2903 



PERFORMANCE ADVANTAGES 

. Durability and Strength: Cement mortars modified with RHOPLEX® E- 
330 are hard tough, and durable. Compared with unmodified mortars, 
polymer-modified mortars have superior flexural, adhesive, and impact 
strengths, as well as excellent abrasion resistance. They are especially 
useful where thin sections are desirable and where excessive vibration 
and heavy traffic are encountered. 



• Adhesion- RHOPLEX® E-330-modified cement mortars have excellent 
adhesion to a variety of surfaces, such as concrete, masonry, brick, wood, 

and metals. — 

. Resistance Properties:Cement mortars prepared with RHOPLEX® E-330 
are resistant to many industrial chemicals and have excellent resistance 
to ultraviolet light and heat. They dry to a uniform color with no tendency 



toward yellowing or discoloration. 



• Curing Advantages: For optimum physical properties, cement mortars 
modified with RHOPLEX® E-330 should be air-cured at ambient 
temperature and relative humidity. Unlike unmodified mortars, which 
require laborious moist curing conditions for optimum strength properties, 
polymer-modified mortars should not be cured under these conditions. 

• Storage Advantages: RHOPLEX® E-330 emulsion is sediment-free and 
stable to a minimum of five cycles of freezing at -15°C and thawing at 
25°C. 



TYPICAL PHYSICAL PROPERTIES 


Appearance 






White, milky liquid 


Solids content, % 






47 ± 0.5% 


pH, when packed 






9.3 to 10.2 


Specific gravity 






1.059 


Pounds per gallon 






3.S 


Freeze/thaw stabil 


ity 




5 cycles 


Minimum film-formation 


temperature 


10°C to 12°C 



RHOPLEX® E-330 is stable for a minimum of five cycles of freezing at -15°C and 
thawing at 25°C. However, in cold weather or after prolonged storage, the emulsion 
should be thoroughly stirred prior to use to ensure a completely homogeneous 
mixture. 

Suggested starting point formulations, test results, and other technical information 
for RHOPLEX® E-330 are noted in the Technical Data Sheets for this product. 

SUGGESTED STARTING FORMULATIONS FOR RHOPLEX® E-330 

Depending upon the particular application involved, a variety of cement mortar 
formulations shown below are useful as starting point systems. 

The quantities of water cited in the formulations below should be considered as rough 
guides. Exact amounts depend on the type and brand of cement, particle size and 
moisture content of the sand, and on the other agents used in the mortar mix. 
Increasing amounts of RHOPLEX E-330 used in the cement mortar require decreasing 
amounts of water for a suitable workable consistency. 

To prepare RHOPLEX E-330-modified mortar for evaluation, thoroughly premix the 
sand and cement. The RHOPLEX E-330, water and antifoamer should be blended 
together and added to the premixed sand and cement. The entire composition is 
mixed thoroughly for about two to four minutes. When preparing mortars for 
application in the field, a portion of the water should be withheld and added gradually 
to the modified mortar mixture until the desired consistency is obtained. This is 
necessary to avoid overly fluid compositions in those cases where the sand is used in 
high moisture content or where other variables affect the amount of water to be used. 

Prior to testing, all mortar specimens were cured for 28 days. Unmodified mortars 



were prepared by both air-cured and wet-cured procedures, whereas the polymer- 
modified samples were all air-cured. The conditions employed for air and wet-curing 
are as follows: 

AIR-CURING CONDITIONS 

• 28 days at 25°C and 50% relative humidity 

WET-CURING CONDITIONS 

• 1 day at 25°C and 90% relative humidity 

• 6 days water immersion at 25°C 

• 7 days at 25°C and 50% relative humidity 

• 7 days water immersion at 25°C 

• 7 days at 25°C and 50% relative humidity 



SUGGESTED STARTING FORMULATIONS 


Ratio of 
Polymer Solids 
to Cement(a) 


0.00 


0.10 


0.15 


0.20 


Material 


Weight 


Weight 


Weight 


Weight 


Sand 


300.00 


300.00 


300.00 


300.00 


Portland Cement 
(Type 1) 


100.00 


100.00 


100.00 


100.00 


RHOPLEX® E-330 
(47% Solids) 


0.00 


21.00 


32.00 


42.00 


Defoamer(b) 


0.00 


0.10(C) 


0.15(C) 


0.20(C) 


Water 


48.00 


29.00 


20.00 


11.00 


Ratio of Water to 
Cement(a) 


0.48 


0.40 


0.37 


0.35 


Ratio of Sand to 
Cement(a) 


3.00 


3.00 


3.00 


3.00 



(a) By weight 

(b) Recommended Defoamers: Nopco NXZ (100% active) - Henkel Corporation, Ambler, PA 
19002-3491 GE Antifoam *60 (30% active) - General Eiectric Co., Silicone Products Deot., 
Waterford, NY 

(c) Suggested minimum of 1% based on polymer solids using 100% active defoamer. More may 
be added, if necessary, to maximize wet density. 



FORMULATION GUIDE WITH RHOPLEX® E- 


■330 


ACRYLIC SPACKLE COMPOUND FORMULATION 


(JK-7S9C) 


Pounds 


RHOPLEX E-330(47%) 






228 


TAMOL® 850(30%) 






2 


Ethylene glycol 






48 


ACRYSOL® ASE-50(28%) 






4 


#8 Marble dustfGeorgia Mc 


rble Co. 


, Tate,Ga.) 


980 


Titanium dioxide(Ti-Pure R- 


■901) 




12 



Tntsl 1 ?74 



were prepared by both air-cured and wet-cured procedures, whereas the polymer- 
modified samples were all air-cured. The conditions employed for air and wet-curing 
are as follows: 

AIR-CURING CONDITIONS 

• 28 days at 25°C and 50% relative humidity 

WET-CURING CONDITIONS 

• 1 day at 25°C and 90% relative humidity 

• 6 days water immersion at 25°C 

• 7 days at 2S°C and 50% relative humidity 

• 7 days water immersion at 25°C 

• 7 days at 25°C and 50% relative humidity 



SUGGESTED STARTING FORMULATIONS 


Ratio of 
Polymer Solids 
to Cement(a) 


0.00 


0.10 


0.15 


0.20 


Material 


Weight 


Weight 


Weight 


Weight 


Sand 


300.00 


300.00 


300.00 


300.00 


Portland Cement 
(Type 1) 


100.00 


100.00 


100.00 


100.00 


RHOPLEX® E-330 
(47% Solids) 


0.00 


21.00 


32.00 


42.00 


Defoamer(b) 


0.00 


0.10(C) 


0.15(C) 


0.20(C) 


Water 


^3.00 


29.00 


20.00 


11.00 


Ratio of Water to 
Cement(a) 


0.43 


0.40 


0.37 


0.35 


Ratio of Sand to 
Cement(a) 


3.00 


3.00 


3.00 


3.00 



(a) 3y weignt 

(b) Recommended Defoamers: Nopco NXZ (100% active) - Henke! Corporation, Ambler, PA 
19002-3491 GE Antifoam -60 (30% active) - General electric Co., Silicone Products Deot., 
Waterford, NY 

(c) Suggested minimum of 1% based on polymer solids using 100% active defoamer. More may 
be added, if necessary, to maximize wet densitv. 



FORMULATION GUIDE WITH RHOPLEX® E-330 


ACRYLIC SPACKLE COMPOUND FORMULATION (JK-7S9C) 


Pounds 


RHOPLEX E-330(47%) 






223 


TAMOL® 350(30%) 






2 


Ethylene glycol 






T-O 


ACRYSOL® ASE-60(28%) 






4 


#3 Marble dust(Georgia Marble 


Co. 


, Tate 


,Ga.) 980 


Titanium dioxide(Ti-Pure R-901 


) 




12 






Mixing Procedure 

Using a double-biaded sigma-type mixer: 

1) Premix the liquid ingredients and charge about 75% to the mixer. 

2) Add sufficient #8 Marble dust and Ti02 to make a thick paste 
(approximately 70% of the dry ingredients) while mixing. 

3) Add the remainder of the liquids and mix thoroughly. 

4) Add the remainder of the dry ingredients. 

5) Cover mixer tightly and mix for about one hour. 

6) About five minutes before the completion of the batch, add 0.3 to 0.4 
lb of Nopco NXZ defoamer (0.25% based on polymer solids). 



VARIABLES AFFECTING CEMENT MORTAR PROPERTIES USING 

RHOPLEX® E-330 

Polymer Modification In general, cement mortars modified with RHOPLEX E-330 and 
air-cured have superior flexural, shear bond adhesion, and impact strengths when 
compared to moist cured, unmodified cement mortars. In addition, polymer 
modification results in improved abrasion resistance and comparable tensile and 
compressive strengths when compared to unmodified mortars. This information is 
presented in the table below and the figures represent average values of a large 
number of samples tested. 



PHYSICAL STRENGTH PROPERTIES OF PORTLAND 
CEMENT MORTAR 



Ratio of 

RHOPLEX® E-330 0.00 0.10 0.15 0.20 

Polymer 



Ratio of water to 

cement(l) °- 43 °- 4 0.37 0.35 

Tensile Strength, psi ~ 



28 day air-cure 235 530 615 355 

28 day wet-cure 535 



28 day air-cure 

+ 7 day water soak ^10 330 35 ° 4 20 

Compressive Strength, psi 



28 day air-cure 2390 5450 5715 



5690 



28 day wet- cure 5795 

28 day air-cure + 

7 day water soak 442 ° 4 ?00 5125 5460 

Flexural Strength, psi 



23 day air-cure 610 1355 1585 1835 

28 day wet-c ure 1070 

28 day air-cure + 7 day 

water soak 735 950 1020 1050 

Shear Bond Adhesion, psi(2) " ~ 



5 



28 day wet-cure 


185(A) 










28 day air-cure + 7 day 
water soak 


140(A) 




290(C) 


300(C) 


330(C) 


Impact Strength, in/lb 


28 day air-cure 


6 




12 


16 


22 


28 day wet-cure 


7 










28 day air-cure + 7 day 
water soak 


9 




11 


13 


18 


Abrasion Resistance, percent 


weight ioss 


(3) 








28 day air-cure 


23.3 




1.70 


1.15 


1.57 


28 day wet-cure 


5.07 











(1) The water content of the mortars was adjusted to provide equivalent workability, i.e., the 
polymer-modified mortars were prepared at water contents necessary to give the same slump 
diameter which was equivalent in workability to the unmodified mortar controls at 48 percent 
water content. This procedure is described in the ASTM "Flow Rate" test *C-230-83. 

(2) Adhesive failure indicated oy (A). Cohesive failure indicated by (C). 

(3) Lower values indicate better aprasion resistance. 



VARIABLES AFFECTING CEMENT MORTAR PROPERTIES USING 

RHOPLEX® E-330 

Density 

The graph below shows the effect of density variation on the tensile strength of 
cement mortar modified with RHOPLEX E-330. As the density increases, so does the 
tensile strength. Similarly, one can improve the compressive, flexural impact and 
adhesive strengths by increasing the mortar density. Therefore, when modifying 
cement mortars with RHOPLEX E-330 it is important to minimize the air entrainment 
due to foaming. By using an appropriate amount of antifoamer it is possible to get 
high density, polymer-modified mortars with excellent strength properties. In general 
the wet density of a latex-modified cement mortar should be at least the same as 
unmodified mortar. In most cases the wet density will be 2.0 g/cm3 or higher. 

TENSILE STRENGTH VS DENSITY 

700 



600 
500 
400 
300 
200 



100 








I 



















J^\ 








RMo; 
Wan 


i i 

plat =-330/Cement = 0.15 




Sarx 

7 2a- 


1/Cemerrt = 3/1 
f Aif.Cure 





1.55 1.65 1.75 1.85 1.95 2.05 2.15 
Density (g/cm : ) 



VARIABLES AFFECTING CEMENT MORTAR PROPERTIES USING 

RHOPLEX® E-330 



Length of Cure 

All cement mortars continue to cure with the passage of time. It is believed that it 
takes about 28 days for both a polymer-modified and an unmodified cement mortar 
to obtain approximately 90 percent of their ultimate physical properties. The graph 
below shows the increase in tensile strengths of RHOPLEX E-330-modified and 
unmodified mortars as a function of time. Similar behavior also occurs in other 
physical strength propenies. 

Curing Conditions 

To obtain maximum physical strength properties, RHOPLEX E-330-modified cement 
mortars should be air-cured at ambient temperature and relative humidity, avoiding 
the use of moist curing techniques, a laborious procedure used with unmodified 
mortars to obtain optimum properties. 



TENSILE STRENGTH VS DAYS AIR- 
CURE 

1000 



— 800 

a; 600 

uS 

_o 

■5 4 00 

c 

t- 

200 









3/1 






Sand/oemem = 


^~^~~ 




\ 




* I I I 
RHOPLEX E-330/Cament = Q.20 
Waler/Cament = 0.30 


















^_^L- — - 1 


i 






Polymer/ 1 Cerr 
Waier/Cemer 


ent • C 
rt mG.4 


5 



14 21 28 35 42 
Air-Curing Time (Days) 



49 



56 



VARIABLES AFFECTING CEMENT MORTAR PROPERTIES USING 

RHOPLEX® E-330 

Water Level 

The amount of water that should be used in a cement mortar depends on the type 
and brand of cement used, the particle size and moisture content of the sand used, 
the additional ingredients of the mortar mix, and the working consistency desired for 
the particular application. As a general rule, water should be held to the lowest 
amount needed to achieve a suitable working consistency. By using a minimum 
amount of water, maximum strength properties are obtained. 

The effect of the water/cement ratio on tensile strength at a constant polymer level is 
shown in the graph below: 



■ 



TENSILE STRENGTH VS 
WATER/CEMENT 



1200 
._. 1000 

M 

a. 

2* 800 

S 600 
en 

S 400 
in 

C 
0) 

I- 200 



RHOPLEX E-330/Cement « 0.20 


7 Day Air-Cure 


, 


/ 7^*J 


/ ' * 










I 





0.25 



0.30 0.35 0.40 
Water/Cement Ratio 



0.45 0.50 



SAFE HANDELING INFORMATION 

Animal toxicity screening tests conducted on closely related analogs of RHOPLEX® E- 
330 suqgest that this product should be essentially nontoxic by single acute oral or 
dermal exposure and that it may also be a mild to moderate skin and eye irritant In 
addition, many of the components of cement used in conjunction with RHOPLEX E- 
330 may also possess significant skin and eye irritation potential. 

The Rohm and Haas Company maintains comprehensive and up-to-date Material 
Safety Data Sheets (MSDS) on all of its products. These sheets contain pertinent 
information that you may need to protect your employees and customers against any 
known health or safety hazards associated with our products. 

The Rohm ^nd Haas Company recommends that you obtain copies of our Material 
Safety Data Sheets from your local Rohm and Haas representative on each or our 
products prior to its use in your facilities. We also suggest that you contact your 
supplier of other materials recommended for use with our products ror appropriate 
health and safety precautions prior to their use. 



ACRYSOL® RHOPLEX, and TAMOL® are registered trademarks of Rohm and Haas 
Company or of its subsidiaries or affiliates, and are intended to designate goods 
marketed in North and South America; the same goods may be marketed in other 
countries, generally under the Company trademark designations. 

These suggestions and data are based on information we believe to be reliable. They 
are offered in good faith, but without guarantee, as conditions and methods or use of 
our products are beyond our control. We recommend that the prospective user 
determine the suitability of our materials and suggestions before adopting them on a 
commercial basis. 

Suggestions for uses of our products or the inclusion of descriptive material from 
parents and the citation of specific patents in this publication should not be 
understood as recommending the use of our products in violation of any patent or as 
permission or license to use any patents of the Rohm and Haas Company. 



5 



APPENDIX Q: 
Rohm and Haas Product Materials Safety Data Sheets 



. S 



MATERIAL SAFETY DATA SHEET 
Rohm and Haas Company 



1. CHEMICAL PRODUCT AND COMPANY IDENTIFICATION 



RHOPLEX™ E-330 Emulsion 



Product Code 
Key 



66580 
905688-9 



MSDS Date 



08/05/99 



RHOPLEX™ is a trademark of Rohm and Haas Company or one of its subsidiaries or affiliates 



Italics denote a revision from previous MSDS. 



COMPANY IDENTIFICATION 


EMERGENCY TELEPHONE NUMBERS 


Rohm and Haas Company 
100 Independence Mall West 
Philadelphia. Pa 19106-2399 


HEALTH EMERGENCY : 215-592-3000 
SPILL EMERGENCY . 215-592-3000 
CHEMTREC : 800-424-9300 



2. COMPOSITION/INFORMATION ON INGREDIENTS 



No 



CAS REG NO 



P(BA/MMA) 



]2>8>2-3/-3 



Residual monomers 



\\Not Required 



Aqua ammonia 



11336-21-6 



Water 



7732-18-5 



WEIGHT (%) 



46-48 



<0.05 



0.3 MAX 



'2-54 



_J 



Polvmenc description(s) presented in this section are the U.S. Toxic Substances Control Act (TSCA) 
definitions. 

See Section 8. Exposure Controls / Personal Protection 



3. HAZARDS IDENTIFICATION 



3 



z&o 



Primary Routes of Exposure 

Inhalation 

Eye Contact 
Skin Contact 

Inhalation 

Inhalation of vapor or mist can cause the following: 

- headache - nausea - irritation of nose, throat, and lungs 

Eye Contact 

Direct contact with material can cause the following 

- slight irritation 

Skin Contact 

Prolonged or repeated skin contact can cause the following: 

- slight skin irritation 



4. FIRST AID MEASURES 



Inhalation 

Move subject to fresh air. 

Eye Contact 

Flush eyes with water. Consult a physician if irritation persists. 

Skin Contact 

Wash affected skin areas thoroughly with soap and water. Consult a physician if irritation persists. 

Ingestion 

If swallowed, give 2 glasses of water to drink. Never give anything by mouth to an unconscious 
person. Consult a physician. 



5. FIRE FIGHTING MEASURES 

. 61 



Flash Point ]Noncombustible 


|Auto-ignition Temperature Not Applicable 


|Lower Explosive Limit [Not Applicable 


|Upper Explosive Limit |Not Applicable 



Unusual Hazards 

Material can splatter above 100C/212F. Dried product can burn. 

Extinguishing Agents 

Use extinguishing media appropriate for surrounding fire. 

Personal Protective Equipment 

Wear self-contained breathing apparatus (pressure-demand NIOSH approved or equivalent) and full 
protective gear. 



6. ACCIDENTAL RELEASE MEASURES 



Personal Protection 

Appropriate protective equipment must be worn when handling a spill of this material. See SECTION 
8, Exposure Controls/Personal Protection, for recommendations. If exposed to material during 
clean-up operations, see SECTION 4. First Aid Measures, for actions to follow. 

Procedures 

Contain spills immediately with inert materials (e.g. sand, earth). Floor may be slippeiy; use care to 
avoid falling. Transfer liquids and solid diking material to separate suitable containers for recovery 
or disposal. Keep spectators away. 
CA UTION: Keep spills and cleaning runoff out of municipal sewers and open bodies of water. 



7. HANDLING -AND STORAGE 



Storage Conditions 

Keep from freezing; material may coagulate. TJte minimum recommended storage temperature for 
this material is I C/34F. The maximum recommended storage temperature for this material is 
60C/140F. 

Handling Procedures 

Monomer vapors can be evolved when material is heated during processing operations. See 



SECTION 8, Exposure Controls/Personal Protection, for types of ventilation required. 



8. EXPOSURE CONTROLS/PERSONAL PROTECTION 



Expo sure Limit Information 



No 



\P(BA'MMA) 



\\Residual monomers 



laua ammonia 



Water 



CAS REG NO 



WEIGHT (%) 



\23852-3/-l 



\\Not Required 



\1336-21-6 



'732-18-5 



\46-48 



\<0.05 



0.3 MAX 



' 7. *J 



ComD. 



No. 



ROHM AND HAAS ! OSHA 



Units TWA 



]M 



25 b 



\None 



ISTEL 



Aon 



P-5 b 



\\None 



TWA 



\\None 



{None 



STEL 



\None 



15 b 



\\None 



ACGIH 



TWA 



\None 



15 b 



\None 



STEL 



\\None 



35 b 



\\None 



a Sot Required 
b As Ammonia 



Vie CAS U of the polymer components) disclosed above provides information about the major 
monomers used to manufacture the product. Trace levels of these monomers may be present. 

Respiratory Protection 

4 respiratory protection program meeting OSHA 1910.134 and ANSI Z88.2 requirements must be 
followed whenever workplace conditions warrant a respirator's use. None required if airborne 
concentrations are maintained below the exposure limit listed in Exposure Limit Information . For 
airborne concentrations up to 10 times the exposure limit , wear a NIOSH approved (or equivalent) 
half-mask, air-purifying respirator. Air-purifying respirators should be equipped with NIOSh 
approved (or equivalent) cartridges for protection against ammonia and methylamine and filters for 
protection against dusts and mists. 

Eve Protection 

Use safety glasses with side shields (ANSIZ871 or approved equivalent). Eye protection worn must 
be compatible with respiratory protection system employed. 



- 



Hand Protection 

The glove(s) listed below may provide protection against permeation. Gloves of other chermcallv 
resistant materials may not provide adequate protection: 
- Neoprene 

Engineering Controls (Ventilation) 

Use local exhaust ventilation with a minimum capture velocity! of 1 00 ft'min. (0.5 m/sec.) at the point 
of vapor evolution. Refer to the current edition of Industrial Ventilation: A Manual of 
Recommended Practice published by the American Conference of Governmental Industrial 
Hygienists for information on the design, installation, use. and maintenance of exhaust systems. 

Other Protective Equipment 

Facilities storing or utilizing this material should be equipped with an eyewash facilitv. 



9. PHYSICAL AND CHEMICAL PROPERTIES 



[Appearance 


\\Milky 


\Color 


\\White 


\State 


\\Liquid 


\Odor Characteristic 


^Ammonia odor 


\pH 


~\\9.3 to 10.2 


1 Viscosity 


\\5 to 55 CPS 


\Specific Gravity (Water = 1) 


_\[l.0to 1.2 


\Vapor Density (Air = I) 


||< 1 Water 


1 Vapor Pressure 


||7 7 mm Hg @ 20°C/68°F Water 


\Melting Point 


\[0°C/32°F Water 


\Boiling Point 


_}[100°C'212°F Water 


\Solubility in Water 


\\Dilutable 


\Percent Volatility 


\\52 to 54 % Water 


Evaporation Rate (BAc = 1) 


||< 1 Water 



See Section 5, Fire Fighting Measures 



10. STABILITY AND REACTIVITY 



ZG4 



Instability 

This material is considered stable. However, avoid temperatures above 1 77C/350F, the onset of 
polymer decomposition. Thermal decomposition is dependent on time and temperature. 

Hazardous Decomposition Products 

Thermal decomposition may yield acrylic monomers. 

Hazardous Polymerization 

Product will not undergo polymerization. 

Incompatibility 

There are no known materials which are incompatible with this product. 



11. TOXICOLOGIC AL INFORMATION 



Acute Data 

No toxicity data are available for this material. 

The information shown in SECTION 3, Hazards Identification, is based on the toxicity profiles for a 

number of acrylic emulsions that are compositionally similar to this product. Typical data are: 

Oral LD50 - rat: >5000 mg/kg 

Dermal LD50 - rabbit: >5000 mg/kg 

Skin irritation - rabbit: practically non-irritating 

Eye irritation - rabbit: inconsequential irritation 



12. ECOLOGICAL INFORMATION 



No data are available for this material. The information shown is based on profiles of 
compositionally similar materials. 

Inherent Biodegradability (OECD 302 B): this type of product is not biodegradable but readily 

bioeliminable (non-inhibiting) 

Activated Sludge Respiratory Inhibition (OECD 209): >I00 mg/l (non-inhibiting) 

Environmental Toxicity 7 

The Environmental Toxicity! data are for a compositionally similar material. 
Algae (Selenastrum capricornutum). 72 Hour EC 50: > 100 ppm 
Daphnia Magna, 48 Hour EC50: > 100 ppm 

1&5 



Rainbow Trout (Oncorhynchus mykiss). 96 Hour LC50: >100 ppm 
Microtox, 15 Minute EC '50: > 300 ppm 



13. DISPOSAL CONSIDERATIONS 



Procedure 

Coagulate the emulsion by the stepwise addition of ferric chloride and lime. Remove the clear 

supernatant and flush to a chemical sewer. 

Landfill or incinerate remaining solids in accordance with local, state and federal regulations. 



14. TRANSPORT INFORMATION 



US DOT Hazard Class i NONREGULATED 



15. REGULATORY INFORMATION 



Workplace Classification 

This product is considered non-hazardous under the OSHA Hazard Communication Standard 
(29CFR 1910.1200). 

This product is not a 'controlled product' under the Canadian Workplace Hazardous Materials 
Information System (WHMIS). 

SARA TITLE 3: Section 311/312 Categorizations (40CFR370) 

This product is not a hazardous chemical under 29CFR 1910.1200, and therefore is not covered by 
Title m of SARA. 

SARA. TITLE 3: Section 313 Information (40CFR 372) 

This product does not contain a chemical which is listed in Section 313 at or above de minimis 
concentrations. 

CERCLA Information (40CFR 302.4) 

Releases of this material to air, land, or water are not reportable to the National Response Center 
under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) or 
to state and local emergency planning committees under the Superfund Amendments and 
Reauthorization Act (SAR.4.) Title III Section 304. 

1£U 



Waste Classification 

Wlien a decision is made to discard this material as supplied, it does not meet RCR.4 's characteristic 
definition of ignitability, corrosivity, or reactivity, and is not listed in 40 CFR 261.33. The toxicity 
characteristic (TC), however, has not been evaluated by the Toxicity Characteristic Leachin^ 
Procedure (TCLP). 

United States 

All components of this product are in compliance with the inventory listing requirements of the U.S. 
Toxic Substances Control Act (TSCA) Chemical Substance Inventory. 

Pennsylvania 

Any material listed as "Not Hazardous" in the CAS REG NO. column of SECTION 2. 
Composition/Information On Ingredients, of this MSDS is a trade secret under the provisions of the 
Pennsylvania Worker and Community Right-to-Know Act. 



16. OTHER INFORMATION 



Rohm and Haas 

Hazard Rating 


Scale 


Toxicity | 1 


4=EXTREME 


Fire ~ ]f | 


3=HIGH 


Reactivity j| 


2=MODERATE 


Special || - | 


1=SL!GHT 


|0=INSIGNIFICANT 



Ratings are based on Rohm and Haas guidelines, 
and are intended for internal use. 



HMIS Hazard Ratings 



HMIS Hazard Ratings: HEALTH = I, FLAMMABILITY = 0, REACTIVITY = 0. 

PERSONAL PROTECTION: See Section 8, Exposure 

Controls/Personal Protection for recommended 

handling of material as supplied: check with 

supervisor for your actual use condition. 

Scale: = Minimal, J = Slight, 2 = Moderate, 3 = Serious, 4 = Severe 

* = Chronic Effects (See Section 3, Hazards Identification) 

HMIS is a registered trademark of the National Paint and Coatings 
Association. 



'■&■ 



APPENDIX R: 

Select American Society for Test Methods Procedures 



G 



INDEX 






INDEX: 

Accelerated Weathering, 4-6, 32, 45-47, 51-59, 62, 85, 109-1 10, 123-126 

Adhesion, 6-12, 52, 54-55, 61, 81, 99, 106, 1 19-124 

Binder, 5, 11, 14-20, 26, 62, 64-70, 80, 97, 1 14, 120, 

Bond Strength, 51,85, 107, 109-115 

Calcium Carbonate (caliche), 5, 13, 15, 19, 20, 22-27, 37-40 

Calcium Sulfate (gypsum) ,13, 19-20, 38-40, 65-66 

Cliff Palace, 12, 16, 17,20 

Gloss, 51,85, 93-96, 101, 122 

Mug House, 2, 12, 16-20 

Petrographic Analysis, 21, 34, 83, 85 

Protien, 70-78 

Reflectance, 51, 85, 93-96, 101, 122 

Salts, 22, 35-36, 85, 99, 

Spruce Tree House, 16, 41, 67 

Square Tower House, 16, 18, 19, 23, 36, 39, 40, 41, 46 

Wettability, 8-9, 77-81,90, 124 



■2.-70 




FINE ARTS LIBRARY 

DEC 9 2002 

UN>V- Or HENNA. 



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