Put the glue in a bucket or pan, and cover it with water; let it stand
until more than half penetrated with water, taking care that it shall not
soak too long, and then pour it off and let it remain until it becomes
soft, when it will be ready for the melting kettle. This is a double
vessel, like a glue kettle. Put the soaked glue into the inner vessel,
and as much water in the outer boiler as it will contain when the inner
vessel is placed in it. When the glue is all melted, (if too thick, add
a little water,) the molasses may be slowly poured into it, and well
mixed with the glue by frequent stirring. When properly prepared, the
composition does not require boiling more than an hour. Too much boiling
candies the molasses, and the roller, consequently, will be found to lose
its suction much sooner. In proportioning the material, much depends
upon the weather and temperature of the place in which the rollers are
to be used. Eight pounds of glue to one gallon of sugar-house molasses,
or syrup, is a very good proportion for summer-time, and four pounds of
glue to one gallon of molasses for winter use. Glue for rollers should be
clear and bright in body, and even in texture, when held up to the light:
it should break short, and with a clear, sharp edge like glass.
[Illustration: MELTING KETTLE.]
For _hand-press rollers_ more molasses should be used, as they are not
subject to so much hard usage as _cylinder-press rollers_, and do not
require to be as strong; for the more molasses that can be used the
better will be the roller. Before pouring a roller, the mould should be
perfectly clean, and well oiled with a swab, but not to excess, as too
much oil makes the face of the roller seamy and ragged. The end pieces
should then be oiled, and, together with the cylinder, placed in the
mould, the upper-end piece being very open, to allow the composition
to pass down between the interior of the mould and the cylinder. The
cylinder must be well secured from rising, before the composition is
poured in, by placing a stick upon the end of it, sufficiently long
to reach above the end of the mould, and be tied down with twine. The
composition should be poured very slowly, and in such a manner as to
cause it to run down only _one side_ of the cylinder, allowing the air to
escape freely up the other.
If the mould is filled at night, the roller may be drawn the next
morning; but it should not be used for at least twenty-four hours after,
except in very cold weather.
To determine when a roller is in order for working, press the hand gently
on it: if the fingers pass smoothly over its surface, it may be said to
be in order; but should it be so adhesive that the fingers cling to it,
it is not sufficiently dry, and should be exposed to the air.
Rollers should not be washed immediately after use, but should be put
away with the ink on them, as it protects the surface from the action
of the air. When washed and exposed to the atmosphere for any length of
time, they become dry and skinny. They should be washed about half an
hour before using them. In cleaning a _new_ roller, a little oil rubbed
over it will loosen the ink: and it should be scraped clean with the back
of a case-knife. It should be cleaned in this way for about one week,
when _ley_ may be used. New rollers are often spoiled by washing them
too soon with ley. Benzine may be substituted for oil; but, owing to its
combustible nature, it is objectionable, as disastrous accidents have
ensued from its use.
Mr. Hansard, an eminent English printer, says, “Take glue, made from the
cuttings of parchment or vellum, fine green molasses, pure as from the
sugar-refiners, and a small quantity of the substance called Paris-white,
and you will have every ingredient requisite for good composition. The
proportion as follows:—
Glue, 2 lbs.
Molasses, 6 lbs.
Paris-white, ½ lb.
Put the glue in a little water for a few hours to soak; pour off the
liquid; put the glue over the fire, and when it is dissolved add the
molasses, and let them be well incorporated together for at least an
hour; then, with a very fine sieve, mix the Paris-white, frequently
stirring the composition. In another hour, or less, it will be fit to
pour into the mould.”
Various patented compositions for rollers may now be had from
type-founders.