Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 192

Glue should be used as hot as possible and in a warm room. The pieces of wood to be joined should be warmed before being put together, and should be well fitted so as to get as little glue in the joint as possible; the glue should be well rubbed in with a brush or by rubbing the two pieces of wood together, and the joint should be made close by clamping, tying, or rubbing, so as to squeeze out all superfluous glue (see pp. 183 to 185). When practicable, as it generally is, except in the case of large veneers, the glued pieces should be worked against each other with gradually increasing pressure, to expel any air between them, and to squeeze out as much of the glue as possible. On the extent to which this is managed much of the strength of the joint depends. The thinner the film of glue between the pieces, the more firmly will they adhere; nothing is gained by leaving a thick layer of glue. The quantity of glue in a joint should be so small that, if the two surfaces are true and bear uniformly on each other, its presence should be denoted only by the hair line which marks the joint. The joint should be made as quickly as possible, and after the pieces are fixed they should remain in a warm place for at least twelve hours. If a joint is broken after it has commenced to set, no amount of clamping will make a good job of it; the glue must all be cleaned off and the joint made again. When the wood is porous it will be of advantage to size the surface with some very weak glue. This will fill up the grain and prevent the glue from sinking into the wood when the joint is made, but let this size be quite dry before gluing, or the effect will be to cool and dilute the glue. The methods of gluing on veneers are described fully later. Great care should be taken that dust, grease, or oil does not get on the surfaces to be joined, or the glue will not hold. Some woods are, however, of a greasy nature. Take teak for instance; if the wood is not thoroughly dry the glue will not set on it, but will peel off. Wood of a greasy nature should not be used where glued joints are employed, or for veneering. A later chapter will deal comprehensively with gluing up joints, etc. (see pp. 183 to 185, and p. 187).

Figs. 489 to 491.—Shortening Hair of Glue Brush by Tying.

Fig. 492.—Glue Brush with Bent Hair.