How to dissolve and how to use.
Glue, which one workman finds all right and from which he obtains
excellent results, may, in the hands of another workman, prove a
failure from many causes, some of which may be that the glue is too
thick, or it may have been chilled before the pieces were clamped
together, or the glue is too thin. The workman has to know from
experience just how thick the glue has to be for the work he has on
hand. A hardwood piece of work requires a thinner glue than soft
wood. The average consistency of glue should be about like that of
thin syrup, and should be applied hot to the work. Sometimes in cold
weather the glue “sets” quickly; then the pieces to be glued should
be heated so that the glue may be kept soft. When the pieces are put
together clamp them up quickly or rub them together, forcing out the
surplus glue from the joint. When work is glued together it should
stand from eight to twelve hours before being handled.
When the end grain of wood has to be glued, it should first be sized,
that is, it should be given a coat of glue and let dry. This fills the
pores of the wood so that when the joint is made it will hold.
There are two kinds of glue, animal and fish glue. Animal glue is made
from the refuse of slaughter houses and tanneries, and the number of
grades and colors are innumerable. Fish glue is made chiefly from the
entrails and skin of fish, and is mostly in liquid form.
To prepare glue, put as much as is needed in the glue pot and cover
over with cold water; then let it soak from six to ten hours, according
to the quantity; after this place the glue pot in the water kettle or
glue heater, and apply heat in any convenient way to the water, which
in turn heats the glue. The use of the two vessels is to prevent the
glue from burning.
Glue should always be used as freshly as possible, for then it holds
better than when it is old.
It can be made to stand the weather by adding boiled linseed oil. Add
the linseed oil to the glue slowly, stirring it all the time, the
proportion of oil to glue being two ounces of oil to sixteen ounces of
glue. Another method of preparing glue to stand the weather, is to use
skimmed milk instead of water when preparing it.