Wood Finishing

a process used to improve the appearance of an article of wood and to protect it from effects of the environment. Many types of finishing that formerly were popular, such as carving, burning, inlaying, and gilding, are no longer commercially used and are preserved only in decorative folk art and in interior design. In modern woodworking the term “finishing” designates the application of a decorative and protective coating of paint, varnish, or other materials on an article of wood. The technology of finishing with paint and varnish has been highly developed.

The choice of a particular paint or varnish depends on the desired appearance of the wood and on the amount of protection required. The coating may be transparent or opaque, and there may be one or several coatings of different kinds. Transparent coatings are produced by applying varnish on a base of synthetic resins, nitrocellulose, desiccating vegetable oils, and other film-forming substances. They are used primarily for articles of wood with a beautiful grain. Varnish is applied by hand with a brush or dabber or is sprayed or poured onto the wood. Sometimes the wood is dipped into the varnish. In some cases, pore-filling and surface priming with special compounds is done before varnishing to reduce varnish consumption. To change the natural color of the wood, the surface is stained, prior to varnishing, with solutions of dyes or chemical reagents that alter the color of the wood without concealing its texture.

Opaque coatings of paints, chiefly enamel paints, are used primarily for products made of wood from coniferous and inexpensive deciduous species, as well as for articles, such as kitchen and hospital furniture, that especially require a protective finishing.

Surfaces covered with paint or varnish may be mat or shiny, depending on the materials used and on the application of the coating. A mat surface generally is obtained by using a mat varnish as the final coating. Highly reflective coatings are obtained by sanding and by applying polishing paste.

Imitation finishing is becoming increasingly popular owing to the shortage of valuable wood. Inexpensive wood can be stained to match the color of valuable wood: the wood undergoes prolonged steeping in a staining solution, or the stain is forced into the pores of the wood. The grain of a rare wood can be applied by the printing method, and paper depicting a rare grain can be glued onto the wood. Laminated plastic may also be used.

Among the special types of wood finishing are relief, surface treatment, and inlay. Relief includes various types of carving, engraving; and embossing. A distinction is made among intaglio, outlining, relief, fretwork, and sculptural carving. Surface finishing involves burning the wood surface or painting it with glue paints, tempera paints, or oil paints. There are three burning techniques: pyrotype (hot printing), pyrography (hot etching), and acid treatment. Painted wood is characteristic of folk art. In the USSR, the painting of turned furniture and decorative articles by Khokhloma craftsmen is particularly noteworthy. In the past, inlay (mosaic, intarsia, incrustation, marquetry) has been the most widely used medium for finishing wooden household objects.