Permanganate of Potash, Soda & Bichromate of Potash

¶ Permanganate of Potash. One of the most widely used chemicals for staining. It comes in violet crystal form to be dissolved in cold water. The colors resulting from its use are beautiful, transparent nut browns. Used considerably for darkening the color of oak and other hard woods. On ash it makes a color which is a very close match for oak. About three ounces of this chemical in two quarts of water makes a medium shade of brown stain on many woods. The first color noted upon application of the potash is violet, but it changes to brown when dry. The stronger the solution, of course., the darker the brown color. Two coats are needed for very dark stains.

¶ When a color finishes up too dark it can be made lighter by a wash of a weak solution of hyposulphite of soda and water. A strong solution of the soda will bleach the brown to a white. This fact makes these chemical solutions handy for matching woods in the furniture factory and elsewhere, as all degrees of color can readily be secured. This peculiarity, the ability to make the stain color the wood dark or medium brown and then bleach it out white is taken advantage of when staining furniture or other wood surfaces parts of which are to be dark brown and parts white. After staining the whole area dark brown, masks ntade of strips of paper are pasted down on the wood parts which are to remain dark brown. Such parts as are to finish white are allowed to remain exposed. Then a wash of hyposulphite of soda is put on over the whole surface. When dry the paper is removed by soaking with water on cloths or blotting paper.

¶ Strong potash and soda solutions should be put on with vegetable fibre brushes or a sponge, using rubber gloves. These chemicals burn the bristles of brushes, that is, hog bristles.

¶ Potash. A white solid caustic alkaline compound. Lye. Potassium. Made from wood ashes and rocks. Pearlasha crude potassium carbonate. Carbonate of potash is a weaker form of caustic potash.

¶ Soda, {Sodium, Caustic Soda, Sal Soda, etc.) A white alkaline compound, sodium carbonate, used in water solutions to stain woods brown. Carbonate of soda is a weaker form of caustic soda.

¶ Soda and potash produce yellowish brown stain colors and dark browns on oak and other woods, depending upon the amount of tannic acid in the wood. And of course when washes of soda or potash are preceded by a wash of tannic acid the color resulting will be a darker yellow or brown.

¶ The fixed alkalies, soda and potash, but not ammonia which is a volatile, when used in strong water solutions as dark stain colors are apt to leave a residue of alkali on the wood, which, if not washed off clean and neutralized with a coat of table vinegar, will saponify any oil mixtures put on top of it.

¶ Bichromate of Potash. The action of this chemical as a stain is much like that of permanganate of potash, except that the bichromate produces colors of a slightly yellower hue than permanganate. On ash, elm and beech the bichromate of potash produces a grayish hue to the yellows. Bichromate of potash is used for dark mahogany colors on real mahogany. A second coat of carbonate of potash put on over bichromate of potash coat produces light tans and browns.

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