(G.) The rich mahogany stain which is so much admired may be made by mixing the same colors as mentioned in (D.), and adding carmine until the desired color is obtained. An oil stain will not give the best results, therefore a water stain should be used, with a piece of gum arabic about twice the size of a pea dissolved in a pint or less of the stain for a binder, or about the same proportion of mucilage. This stain should be cleaned off the same as the oil stain above described.
(H.) Cherry may be darkened by applying nitric acid; other woods may be darkened or aged by using ammonia, potash, or a strong solution of tobacco or coffee. Nitrate of silver, if exposed to the sunlight, gives a beautiful brown.
(I.) A rich brown may be produced by using equal parts of permanganate of potash and sulphate of magnesia, dissolved in water; as many coats as desired may be applied, sanding with number 00 sandpaper between the coats. Better results are obtained if the stain is applied hot.
(J.) A beautiful green of any intensity may be produced by mixing verdigris and indigo in hot vinegar, and applying hot. Several coats may be necessary, sanding between the coats. The indigo should be used cautiously, or the green may have too much of a bluish cast.
(K.) A rich brownish black may be obtained by using a solution of logwood (pulverized) and sulphate of iron, applied in coats in the order named. Each solution should be hot.
(L.) Ebony may be obtained by giving any close-grained wood, cherry preferred, a coat of sulphate of iron, using a weak solution, and after that has dried and been sanded, a coat of solution of nutgalls. If the iron is too strong, a white efflorescence will appear, which in open-grained woods will bring out the grain in strong relief. If this is objectionable, the grain should be filled with a black filler.
(M.) Shellac (see 71, A.) and boneblack, if well mixed, make an ebony finish which is often used upon common work; black varnish sometimes is used the same as black shellac, but for the best work these are not satisfactory, as they do not strike into the wood to the same extent as do acid, turpentine, or water stain.
71. Shellac.—(A.) This is a product of Africa and South America. It is the combination of a secretion of the female of a small insect and the sap of a tree, in the bark of which the insect deposits its eggs. The gum thus formed is gathered, and after passing through various refining processes becomes the shellac known to commerce. It is cut or dissolved by either wood or grain alcohol, when it is ready for use. Some of the best furniture is finished with shellac, and unless continuously exposed to moisture or hard usage, the finish is practically everlasting.
(B.) Shellac finish does not crack as varnish is liable to, neither does its luster dim by exposure to the various gases present in every house, which are due to domestic causes, though most varnishes will do this after some years.
Upon ordinary work, two coats of shellac may be satisfactory, though three coats generally will improve the work sufficiently to make it advisable to apply the extra coat. Shellac should not be laid in too thick coats, or it will pit badly in drying, and make work in rubbing to a surface, which can be avoided if moderately thin coats are spread, though perhaps the greatest advantage in laying thin coats is that the wood may be covered more evenly, and there will be fewer runs and laps visible. Shellac should always be laid with quick strokes, never working over a place already covered; for this work, use a brush as large as possible to do the work without clumsiness.