Hardwood Finishing

Spirit stains are more penetrative than water stains, and dry more quickly; hence they are better adapted for hurried jobs, but otherwise they have no special advantage.

In the use of either spirit or water stains, two coats should always be applied, in order to prevent tiny air bubbles or raised bits of wood fiber causing spots of unstained wood to mar the surface. The second coat should be applied after the first has thoroughly dried out and been lightly sandpapered. For some of the stains that have the nature of a dye, a mordant or chemical to fix or set the color is needed. A solution of alum or of green copperas is gener ally used for this purpose.

Acid and Alkali Stains.

Many woods, espe cially oak and mahogany, become very beauti ful by simply deepening their natural tone. Age will give them this deeper tone, but it is not possible for us to wait fifty or a hundred years for mahogany to assume the deep rich red tones so much admired in old furniture, and we must therefore resort to artificial methods of aging these woods. For this purpose the acid and alkali stains are particularly well adapted. The oldest stain of this kind used, and one of the best, is lime water, or the milk of lime, made by slaking ordinary lime in a sufficient quantity of water. This is brushed over the surface of the wood and allowed to dry, and then the lime is brushed off. If the stain is not deep enough the process is repeated one or more times. The wood is then thoroughly washed, and then sponged over with vinegar to neutralize any traces of alkali that might remain, and which would injure the subsequent varnish coats. The greatest objection to the use of lime is that it is slow. Ammonia, reduced with water to the proper strength, is much quicker than lime.

Various other chemicals are used on woods containing tannic acid—such as oak, ash, ma hogany, etc. They have no effect, however, on dry, pitchy, or sappy wood, such as white or yel low pine or whitewood. Among these chemical stains may be mentioned chromate and bichro mate of potash, which give the golden oak effect on oak or dark mahogany; picric acid, which gives a yellow effect and is specially adapted for toning up walnut; iodine, which produces a beautiful brown stain, but is rarely used on ac count of its expense; caustic soda, which has a darkening effect; and copperas, which is used to set and deepen the colors that have been ob tained. Sycamore and cherry give excellent

effects when deepened in tone with acid, lime, or potash, and then stained with Bismarck brown, a very beautiful aniline stain.

The Fuming Process. Fuming wood gives very beautiful effects where the wood contains tannic acid—especially on oak, but unfortu nately it is not well adapted to standing trim in houses, since it requires an absolutely tight room or box, in which the wood is subjected to the fumes of 26-degree ammonia for twelve hours or more until the desired effect is obtained. A good airing is needed to permit the ammonia gases to escape, before any varnishing is done. Fuming gives results without any raising of the grain or need for sandpapering.

A class of so-called pigment stains that really are not stains are used to produce remarkable effects on white pine, and develop unexpected beauties in that wood. They can be used on quartered oak with good effect, but are not well adapted to any wood of even grain. These stains are made by mixing any transparent pigment color such as would be adapted for oil stains— including chemically pure green and Prussian blue or some of the strong red lake colors—with linseed oil and turpentine to the consistency of a thin paint. This is then applied with a brush, the same as an ordinary paint, and allowed to dry partially, when it is wiped off with a cloth. This wiping off leaves the harder portions of the wood practically bare of color, while the stain has sunk into the softer, more open por tions of the grain.

Preparation of Wood Surface for Varnish ing. It has been said that the skilled finisher will produce a better job with a cheap varnish that he is perfectly familiar with than an aver age mechanic can do with the best varnish on the market if he is unfamiliar with it. The more expensive the varnish, the greater its sensitive ness to atmospheric changes. This is one rea son why it is unwise for the architect to specify special brands of varnish.