When ready for use, the glue should be hot and of the consistency of thin sirup. It must be applied with a brush, in a thin, uniform coating, to both surfaces that are to be joined, and must be well brushed into the pores of the wood. Too much glue will prevent the pieces from coming together in the joint. The application should be made as quickly as possible because the glue begins to cool and set as soon as it is taken from the pot; it will set less quickly if the pieces to be glued are warmed. After the pieces have been put together, they should be rubbed to squeeze out the surplus glue, and finally clamped in place and allowed to remain until dry - at least twelve hours.

In gluing large surfaces, such as veneers which must be secured to their foundations, a considerable amount of apparatus is required. Before the glue is applied, a heating box or chamber, which is maintained at a high temperature by coils of steam pipe, is used to heat the pieces to be united, and very heavy clamps are required to squeeze the superfluous glue from the joint. It is important to remember that while the film of glue uniting two pieces should always be continuous, the pieces themselves should be brought as closely together as possible.

When end grain is to be glued it should first be sized; that is, coated with thin glue, in order to fill the pores of the wood, and allowed to dry before the joint is made. Otherwise, the glue that is put into the joint is drawn off into the grain and becomes useless as a fastening.

An example of good gluing is found in the common lead pencil, the wooden portion of which consists of two strips glued together. The line of the joint can readily be traced upon the end of the pencil, but if the work is well done, it will be found that while the joint is a strong one, the amount of glue between the pieces is so small as to be scarcely visible.

Liquid glues are supplied by the trade. They require no heating and are, therefore, always ready for use.