The application of decorative and protective coatings is an important part of, furnishings industry.
Historically, finishing materials such as fillers, stains polishes were mixed and prepared by the polisher from available raw materials. Today, almost all the polisher's requirements are available ready to use. Some of traditional and modern finishing materials are discussed below. Preparation is basically the same for all wood finishing materials. The surface to be finished be free from dust, dirt, oil or grease and should be properly sanded.
Shellac is the basis of traditional French polish. It is a natural resin which is secrete by insects called lac beetles in South-east Asia. The polish is made by dissolving shellac in methylated spirits. French polish is applied by rubbing the polish into grain of the timber with a polishing pad or 'rubber' and building up the body of coating. French polish is not waterproof and resists abrasion only moderately well and is easily damaged by substances such as chemicals, solvents, spirits, etc.
Nitro-cellulose lacquer is generally sold in concentrated form which has to be thinned with the manufacturer's recommended thinner to brushing or spraying consistency. Nitro-cellulose lacquer dries in a few minutes and is ready to coat again in about two hours. In industrial applications lacquer is sprayed and sometimes finished with a 'pulling rubber' (cotton wadding in a chamois cover) to smooth the surface. Lacquer can also be rubbed back with very fine wet and dry abrasive paper, then finished with a cutting (or rubbing) compound and polish. Lacquers generally have moderately high resistance to abrasion, spirits and water.
Pre-catalysed lacquers (polyureathane ) are based on thermo-setting resins which cure or harden in the presence of a catalyst. The catalyst is pre-mixed with the resins, solvents and other compounds at the time of manufacture. The catalyst reacts with the resins only when the volatile solvents begin to evaporate after application. Pre-catalysed finishes such polyurethane can be sprayed, brushed or rolled, usually drying in three or four hours and allowing up to twenty-four hours between coats. Light sanding is necessary between coats and a fine finish can be achieved by rubbing with very fine wet and dry abrasive paper, cutting (rubbing) compound and car polish. These finishes are highly resistant to abrasion and damage by water and chemicals.
Two-pack polyurethane consists of two sets of compounds, one containing the resins and the other containing the catalyst or hardener. Chemical reaction commences as soon as the two parts are thoroughly mixed. The mixture should be left for a few minutes according to the manufacturer's specifications before spraying, brushing or rolling. The manufacturer's specified time between coats should be followed so that both chemical and mechanical adhesion occurs between successive coats. Two-pack polyurethane can be finished in the same manner as the pre-catalysed type but dries to a much harder and more durable finish.
Oil finishes give a soft, dull lustre to timber. Traditionally, natural oils such as linseed oil were rubbed into the surface of the wood. This is a simple wood finish but is very time consuming. Modern finishes such as Scandinavian oil are generally applied in two stages. A sealer coat is applied in the first stage. When the sealer is property dry the surface should be lightly sanded. The oil is then applied and, while still wet, rubbed into the surface using a fine steel-wool pad, working with the grain. Excess oil should be wiped off and the process repeated if necessary after the first coat is properly dry. Scandinavian oil produces a reasonably durable, open grain, satin smooth finish which can easily be revived by rubbing in another oil coat when required.
Wax polish, made from beeswax and other waxes dissolved in turpentine or mineral spirits is seldom used alone as a finish, but applied over other finishes as added protection. Several proprietary brands are available. Producing a satin sheen it is often seen on fine cabinetwork, but has low resistance to heat and moisture.

Enamels are manufactured by adding pigments to the resins, solvents and other materials that make up the liquid body of this finishing material. Traditionally enamels were based on natural resins which tended to oxidise over time, with some loss of quality in the finish. Modern enamels contain more synthetic resins. Those that can be brushed or rolled are usually thinned with mineral turpentine, but special spraying enamel which dries by chemical reaction, usually requires a special thinner.
Enamels provide a reasonably hard and durable surface, usually available in a range of finishes such as gloss, semi-gloss and matt.
Acrylics are versatile finishing materials which range from emulsified water) wall paint to acrylic auto finishes. Acrylic water based wall paint are easy to use and provide a flexible and reasonably durable, washable finish. They dry quickly and are usually available in semi-gloss, satin and matt finishes. Brush and rollers wash out with water. Spraying acrylics such as those used in the automobile and furniture industries consist of acrylic compounds, volatile solvents, pigments and other materials which dry chemically to a very durable, usually hi-gloss finish. A special solvent is usually required for thinning and clean up.
Furniture finishes can range in appearance from a deep shiny glass-like look, to a dull surface which reflects very little light. Manufacturers of finishing materials often vary in their use of terms to describe the finish of their product, for example, full gloss or high gloss (hi-gloss), low sheen or satin, matt or flat. Modern finishing materials are chemically engineered so that they dry to the type of finish stated on the label. However, mechanical or other means can sometimes be used to alter or enhance the finished appearance, as was the practice in traditional surface finishing. Some common terms/finishes are described below as well as methods of enhancing finishes for modern plastic materials.
Gloss finishes were sometimes called mirror finishes and were traditionally achieved by extra rubbing/pulling, spiriting and burnishing with appropriate materials. A good gloss finish with modem plastic materials may not require as many coats as a hi-gloss finish but could be enhanced using the same techniques. A gloss finish doesn't have the deep glass-like appearance of a hi-gloss finish.
Satin finishes have an attractive soft lustre that reflects less light than a gloss finish. Because of this, it is often argued that a satin furniture finish shows the natural beauty of the timber to better effect than the glossier finishes. A glossy surface could be given a satin finish by careful rubbing along the grain with very fine steel wool dipped in a suitable wax polish.
Matt finishes are quite dull and are not often used as a high quality clear furniture finish. A clear matt furniture finish is more likely to be used where the intention is to provide a protective coating without trying to enhance the natural beauty of the timber. A glossier surface could be given a matt finish by rubbing along the grain with fine steel wool then applying a cut and polish product.
The terms hi-gloss, gloss, satin and matt described above are also used to describe the finish on pigmented finishing materials. The term pigmented refers to the addition of compounds which change the colour of the base constituents of the material. For example, in the manufacture of house paint, or even simply adding stain to colour a clear furniture finish.

Manufactured furniture is often constructed from cheap timber and stained to look like more expensive varieties. Stains are also used to improve uniformity of timber colour in a furniture piece before applying finishing materials. The colour and intensity of stain should always be tested on a similar piece of timber before application. Stain should be applied to the bare wood with a brush and excess stain wiped off with a soft cloth in the direction of the grain. There are three main types of stain in general use; oil stain, spirit stain and water stain.
Oil stains consist of oil-soluble dyes dissolved in oils such as turpentine. They are easy to apply but may tend to fade over time.
Water stains contain water-soluble dyes. They penetrate the wood fibres very well and are reasonably fade resistant. Water stains can raise the grain of the timber when applied. Small wood fibres stiffen and cause roughness on the timber surface. This can be avoided by wiping over the surface with a wet cloth, allowing it to dry and sanding before applying the stain.
Spirit stains consist of dyes dissolved in methylated spirits or alcohol. They work well on open grained timber but are not generally suitable for very close grained timbers. They do not penetrate as well as water stains and are less fade resistant.
The range of colours in readily available proprietary stains closely follows the colours of commonly used cabinet timbers, for example, maple, cedar, mahogany, etc. Stains can be lightened in colour by breaking down with the appropriate solvent. As well as staining the wood fibres there are several other methods of creating aesthetic changes to the appearance of timber. A popular method is liming.
Limed finishes give the appearance of weathered whitewash. Liming preparations were traditionally mixed by the polisher from whiting, coloured dye and a solvent such as turpentine. Proprietary liming compounds are usually available in light shades of colours such as grey, blue or green. Liming works best on open grained timbers such as Tasmanian Oak. The liming material is rubbed into the grain, and then wiped off the surface, leaving the coloured material in the grain, but exposing the character of the timber. When dry, the surface would be coated with a clear finish.