The Golden State: Where & How to Live, Secure, Visit, Enjoy and Thrive in California
Coloring Finishing And Painting Wood
28. Permanency of Oil-Soluble Coal Tar Stains.—It is said by some dealers in wood-stains that aniline and other coal-tar oil- and spirit-stains fade more than water-soluble coal-tar dyes do. This statement is especially true, as far as spirit-stains are concerned, because they are made of fugitive basic dyes, which manufacturers and chemists admit are not fast to light and permanent, tho brilliant when first used. Oil-soluble coal-tar dyes now being made are often more permanent than basic dyes which are used for spirit-stains, and are recommended for use on wood by some reliable manufacturers. These oil-stains are used quite extensively, and are proving to be fairly satisfactory; but experts say that they do not possess a fastness to light equal to that usual with water-soluble acid coal-tar dyes.
29. Shellac-Wash over Volatile Oil-Stains.—Lifting of the stain by after treatments of filler or shellac is a common fault of volatile oil- and spirit-stains. Volatile oil-stains are not much changed by a filler, however, if a thin coat of shellac, mixed in the proportion of one part of liquid shellac to seven or eight parts of alcohol, is applied over the stain and allowed to dry before filling. Shellac in its full strength from the can should not be used on porous woods that require a filler until after the filling is finished. A very thin shellac coat, called a shellac-wash, may be used over a stain without filling the pores to such an extent that a filler will not have proper anchorage to hold it in place.
Varnishes cannot be applied directly over any of the oil-stains without probable loss in clearness of tone, because the solvents used in all cases are the same or similar, and some of the coloring-matter may be "lifted" and mix with the varnish-coat, thus producing a muddy or cloudy effect, and a loss of transparency.
Volatile oil-stains, especially those containing benzol as a solvent, penetrate very deeply into the wood in comparison to pigment oil-stains, and do not dry as readily as is indicated by appearances on the outside. It is best to allow at least 24 hours for drying before a shellac-wash is applied over a volatile oil-stain.
Sometimes, in order to secure certain tone or color effects, the shellac-wash is omitted between the coats of stain and filler. In all cases, in order to prevent "bleeding" of the coal-tar oil-stains into the varnish-coats, it is important that one or more coats of shellac be applied to the stained or stained and filled wood before any varnishing is done.
