The Technique of FURNITURE MAKING
Restoration, repairs and wood finishing. Structural repairs
The repair of modern everyday furniture usually calls for cutting out and replacing broken parts, fixing false tenons or dowels to fractured joints, strengthening joints with metal straps, insets or angle pieces, renewing whole members where necessary, and in general applying normal cabinet-making skills. Valuable antique furniture repairs require expert know-how with carefully matched old wood, scraps of old saw-cut veneer, and a keen appreciation of period, colour and patina, together with considerable skills in carving, veneering, inlaying, marquetry cutting, staining, polishing and lacquering, etc. Any such antique repairs should not be undertaken without considerable experience of the particular type of work, for repairs inexpertly done or out of period can detract from, or even destroy, the market value.
Generally speaking, where structural joints have failed, part or all of the construction will have to be taken apart, for there is little point in squeezing glue into the shoulders of a loose tenon and expecting it to hold. Most old work can be knocked apart fairly easily, although a firm but not necessarily heavy hand may be needed. However, modern adhesives may resist parting, and discretion is, therefore, necessary. Joints filled with old hide glue, usually in thick layers, will have to be cleaned out with repeated applications of hot water; they can then be packed up with veneer slips to make up the slackness, and reglued with either hide or synthetics. If the furniture is antique and valuable, great care must be taken to disturb as little of the existing surfaces as possible, and to incorporate only the minimum of new wood, for extensive renovations will always detract from the value. Worm-eaten timbers must be treated if the worm is still active, crumbling parts cut away or built up as described later. If the joints are broken altogether, either dowels or false tenons can be fitted, or new sections scarfed in (see Scarf joints, p. 186). Figure 542:8 shows a false tenon fitted; 542:9 a new section of rail inserted and strengthened with a pad or web if it is load-bearing, while 542:7 is a long scarf joint to a broken chair leg which will need gluing only if the scarf is long enough.
A recent development in the repair of valuable antique furniture has been the use of Araldite epoxy resin adhesive (CIBA [ARL] Ltd) with suitable reactive diluents, fillers and colorants. This type of glue has excellent adhesion to wood, high moisture resistance and, most importantly, negligible shrinkage in curing, so that it can be built up into solid sections without the usual cracking, crazing and disruption of normal adhesives which will only permit thin lines of glue. In particular, worm - eaten timbers can be repaired, restored and strengthened by surface application or penetration, and 541 shows a French marquetry cabinet richly veneered with marquetry patterns of kingwood, ebony, tortoise-pewter and staghorn which was recently restored in the Department of Conservation of the Victoria and Albert Museum in London. In this case parts of the stand seriously ravaged by woodworm were cleared away and then made good with a liquid Araldite formulation. Plastic wood formulations can also be used with Araldite to build up missing parts, and the techniques are applicable to a wide range of materials, metal, wood, plastic, terracotta, etc. The CIBA (ARL) Ltd technical bulletin Araldite in the Restoration of Antiquities gives specific examples.
