—Stains are used to darken the high lights of wood preparatory to the application of a relatively darker filler. By varying the intensity of the stain different results may be obtained with the same color of filler. Stains are also used without fillers.
There are three kinds of stains: (1) water, (2) oil, (3) spirit. Each kind has its advantages and its disadvantages.
Wood stains are cheap, penetrate the wood deeply, and are transparent. They cause the grain of the wood to “rough up,” however, and for this reason are used mainly upon hard woods which require darkening before the application of a filler. The wood is sanded before the filler is applied. Where water stain is not to be followed by filler, it is customary to thoroughly moisten the surface to be covered with water alone. After this has dried, the surface is sanded with fine paper and the stain applied. The stain does not raise the grain as it otherwise would.
Water stains may be applied with a brush or a sponge. They are sometimes heated that they may enter the wood more deeply. Any coloring matter that can be dissolved in water will make a wood dye or stain.
Oil stains, like water stains, are often used to stain wood before filling. They are more generally used where no filling is desired. They are easier to apply evenly than water or spirit stains. They do not raise the grain of the wood like the other stains. On the other hand, they do not penetrate and therefore cannot color hard woods dark. Neither do they give the clear effects.
Most oil stains are applied with a brush, after which the surface of the wood is immediately wiped clean with a cloth.
Spirit stains are but little used where surfaces of any size are to be covered. They are expensive, fade easily, and are hard to apply evenly.
They are applied with a brush and dry very quickly.
A stain which penetrates deeply and is clear is obtained by placing the wood in a closed receptacle in which is placed a dish of concentrated ammonia. The fumes of this liquid cause a chemical change to take place, giving to the wood a rich nut-brown color.