The Technique of FURNITURE MAKING

BALANCING VENEERS

Veneers laid with hide glue will pull even the thickest groundwork/substrate into cup as it dries out, and even resin glues with their reduced moisture content will cause slight warping. If the groundwork is firmly anchored to a heavy supporting frame or locked in a carcass construction it may not call for additional treatment, although solid wood bases should always be veneered on the heart or rounded side to equalize the natural pull (287:5, 7); but in all unsupported work the reverse side must be treated with a balancing veneer (287:8). Ideally, this balancing or 'backing' veneer should be of the same thickness and of similar or comparable species as the face veneer, but in practice balancing veneers are usually makore (cherry mahogany), African mahogany, sapelewood, etc. They are laid with the grain direction similar to the face veneers, but the joints need only be cut and fitted together without matching unless the work is visible. Balance veneering is sometimes referred to as Counter veneering, but it should not be confused with the latter which is a distinct process described on p. 307.

FLATT(EN)ING VENEERS

Only experience will tell whether a buckled veneer can be laid satisfactorily without preliminary flattening. A good veneer-press, whether screw operated, hydraulic or vacuum, will flatten most stubborn veneers, but it may be at the expense of extensive splitting and cracking; therefore badly crumpled or spiteful veneers should always be flattened, using either water alone or a weak solution of glue size (one part glue to five parts water). The veneers

should be thoroughly moistened and flattened between warm boards with light cramping/ clamping pressure or weighted down. They should be turned occasionally to prevent them sticking, and pressed individually and not in a pack unless interleaved with cellophane or waxed hardboard. Oily woods such as rosewood and satinwood do not require moistening and can be flattened with heat alone. Either hide glue or a very weak mix of resin glue and water can be used for size, for resin glue will take over either, and the flattened veneers must be dried thoroughly before laying, keeping them between weighted boards until ready for use. If the veneers have split open during the flattening—and strong burrs and curls are sometimes prone to this—only actual experience will tell whether the split can be pulled together and taped in position. Usually it is advisable to accept the split, slit the sheet through and joint together or patch the gap, for if a stubborn sheet is arbitrarily pulled together it may buckle further up during the pressing. If the splits are wide open they can be covered with gummed paper strip on the face and filled on the underneath with Brummer stopping. which will prevent the glue forming a glass-hard filling in the crack. The Brummer can then be scraped out in the final finishing, and the crack patched or filled with suitable filler.

REPAIRING BLISTERS

Blisters and loose patches can be located by tapping with the finger-nail to disclose a hollow sound, or the fingertips brushed rapidly backwards and forwards which gives a slight whisper over the hollow places. Contrary to the general idea, blisters in veneers laid with resin glues are by no means difficult to repair. The veneer should be slit with a razor-blade or sharp knife along the grain, fresh glue inserted, rubbed hard with the pein of a hammer to expel the surplus glue, taped with paper or cellulose tape, covered with a warmed steel scraper or wood block and weighted down for a moment or so. A soldering-iron or electric iron can be used, but all the excess glue must be squeezed out first or the heat will fuse it into a solid lump under the veneer. If blisters occur in very pale or delicate woods, a piece of white blackboard chalk rubbed along the edges of the cut will help to disguise the scar, and in fact all joints in pale woods can be treated in this way, keeping the chalk to the outer edges of the joints only. (Hide glue mixed with flake-white and Salisbury glue [rabbit skin glue] were used for delicate inlays in traditional work, and both types are still obtainable.)