CHAPTER Vn
BEATING OF VARIOUS FIBRES AND THE CHARACTERISTICS
THEY IMPART TO PAPER
COTTON—LINEN—WOOD PULP—ESPARTO—STRAW
Cotton.—Cotton may be used to produce a great variety of papers. In
practice the use of new cotton fibres is limited to the making of high-class
papers, on account of the high cost of the raw material, and the power and
labour consumed in beating, making, tub-sizing and finishing. This fibre is
supreme for very strong loan, ledger paper, thin banks and the best qualities
of writing and drawing papers.
The most durable, though perhaps not the most absorbent, blottings are
made from new cottons. The degree of fibrillation given to these papers
varies to extreme limits. Thus, for a strong loan of the substance of Large
Post 21 lb., from 6 to 8 hours' beating may be required, while a very close
and clearly water-marked writing paper of the same substance and quality
will take from 2 to 4 hours.
Since in most 'fine' mills both of these papers will have to be produced
by the same beating engines, it is a matter of the highest skill to manipulate
the rolls to fibrillate the loan properly if the tackle is moderately sharp. On
the other hand, the cutting rather than fibrillating of the fibres, for the writing
paper, would be much easier to accomplish. If the tackle is dull and blunt,
the difficulty would be to get the fibres for the writing paper cut fine enough
without too much fibrillation taking place. Again, the plates and bars wear
down and become dull as time goes on, and this renders all records of roll
pressure useless, since the conditions are constantly changing. Thus we are
left, in the long run, dependent on the skill of the beaterman who knows the
conditions and beats according to his judgment. Therefore, though state-
ments of beating time might conceivably be given for different weights and
qualities of paper, they would be correct only in a very general sense, and
only in that sense can they be given. For instance, if the paper we are con-
sidering (a strong loan) were being dealt with by four beaters, of which one
had a fresh and consequently sharp pkte, the beaterman could not by any
possible manipulation of that beater give the stuff in it the same fibrillation as
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