The merits of these two classes of stains may be stated briefly. Water
stains enter more deeply into the pores of the wood because of their
lighter body. The hard parts of the surface hold practically none of
the stain and constitute the high lights of the finished surface. But
water stains raise the grain and make sand-papering necessary to bring
the surface flat again. For this reason, some polishers first give a
coat of water to raise the grain and when dry sand-paper flat before
staining.
Oil stains do not raise the grain, but owing to their heavier body
do not penetrate so deeply and more of the stain is lost in rubbing
off. Oil has a tendency to darken wood, so that wood stained with oil
colours has a tendency to become clouded or muddy with age.
For staining old work, oil stains should be used rather than water
stains. Old work has the pores already filled and water has little
chance to penetrate.
Some chemicals and aniline dyes are very satisfactory. Bismarck brown,
which may be bought at the chemist's as a powder, is soluble in alcohol
and gives a rich reddish brown. It is very powerful and a very small
quantity is necessary. Bichromate of potash comes in the form of lumps
and crystals. It is soluble in water. Put half a dozen crystals in a
quart milk bottle of water and allow it to stand over night. Warm or
hot water will dissolve the crystals more quickly. It is to be put on
with a brush and gives rich brown tints, the shade depending on its
strength, the kind of wood and the number of coats. It gives excellent
results on oak and chestnut, and is used to "age" bay wood to a dark
mahogany, while several coats of it will bring white wood to the colour
of natural black walnut.
Each coat must be allowed to dry and then be rubbed flat with fine
sand-paper.
This treatment may be followed by two or three coats of orange shellac,
rubbed down.
For "antique" finish on oak or chestnut, dissolve lampblack in
turpentine, mix with filler and proceed with polishing as explained.
A decoction of logwood is often used to produce dark and even black
effects. The logwood extract is cheap and comes in the form of gum
or resin. Several lumps of this are boiled in a gallon of water and
applied as any water stain.
Acetate of iron, made from iron filings and vinegar, is used for dark
browns occasionally. The filings should be allowed to stand for several
days in the vinegar. The acid present is acetic. It unites with the
iron forming the acetate of iron.