_STAINS AND IMITATIONS._
In consequence of the high price demanded for furniture made of the
costly woods, the art of the chemist has been called into requisition to
produce upon the inferior woods an analogous effect at a trifling
expense. The materials employed in the artificial colouring of wood are
both mineral and vegetable; the mineral is the most permanent, and when
caused by chemical decomposition within the pores it acts as a
preservative agent in a greater or less degree. The vegetable colouring
matters do not penetrate so easily, probably on account of the affinity
of the woody fibre for the colouring matter, whereby the whole of the
latter is taken up by the parts of the wood with which it first comes
into contact. Different intermediate shades, in great variety, may be
obtained by combinations of colouring matters, according to the tint
desired, and the ideas of the stainer. The processes technically known
as "grounding and ingraining" are partly chemical and partly mechanical,
and are designed to teach the various modes of operation whereby the
above effects can be produced. We will commence with
=Imitation Mahogany.=--Half a pound of madder-root, and two ounces of
logwood chips boiled in a gallon of water. Brush over while hot; when
dry, go over it with a solution of pearlash, a drachm to a pint. Beech
or birch, brushed with aquafortis in sweeping regular strokes, and
immediately dried in front of a good fire, form very good imitations of
old wood. Venetian red mixed with raw linseed-oil also forms a good
stain.
The following is a method in common use by French cabinet-makers. The
white wood is first brushed over with a diluted solution of nitrous
acid; next, with a solution made of methylated spirits one gill,
carbonate of soda three-quarters of an ounce, and dragon's blood a
quarter of an ounce; and a little red tint is added to the varnish or
polish used afterwards. Black American walnut can be made to imitate
mahogany by brushing it over with a weak solution of nitric acid.
=Imitation Rosewood.=--Boil half a pound of logwood chips in three pints
of water until the decoction is a very dark red; then add an ounce of
salt of tartar. Give the work three coats boiling hot; then with a
graining tool or a feather fill in the dark markings with the black
stain. A stain of a very bright shade can be made with methylated
spirits half a gallon, camwood three-quarters of a pound, red-sanders
a quarter of a pound, extract of logwood half a pound, aquafortis one
ounce. When dissolved, it is ready for use. This makes a very bright
ground. It should be applied in three coats over the whole surface, and
when dry it is glass-papered down with fine paper to a smooth surface,
and is then ready for graining. The fibril veins are produced by passing
a graining tool with a slight vibratory motion, so as to effect the
natural-looking streaks, using the black stain. A coat of the bichromate
of potash solution referred to on page 4 will make wildly-figured
mahogany have the appearance of rosewood.
=Imitation Walnut.=--A mixture of two parts of brown umber and one part
of sulphuric acid, with spirits of wine or methylated spirits added
until it is sufficiently fluid, will serve for white wood. Showy
elm-wood, after being delicately darkened with the bichromate solution
No. 1, page 4, will pass for walnut; it is usually applied on the cheap
loo-table pillars, which are made of elm-wood. Equal portions of the
bichromate and carbonate solutions (see page 4), used upon American
pine, will have a very good effect.
Another method for imitating walnut is as follows: One part (by weight)
of walnut-shell extract is dissolved in six parts of soft-water, and
slowly heated to boiling until the solution is complete. The surface to
be stained is cleaned and dried, and the solution applied once or twice;
when half-dry, the whole is gone over again with one part of chromate of
potash boiled in five parts of water. It is then dried, rubbed down, and
polished in the ordinary way.
The extract of walnut-shells and chromate of potash are procurable at
any large druggist's establishment. A dark-brown is the result of the
action of copper salts on the yellow prussiate of potash; the sulphate
of copper in soft woods gives a pretty reddish-brown colour, in streaks
and shades, and becomes very rich after polishing or varnishing.
Different solutions penetrate with different degrees of facility. In
applying, for instance, acetate of copper and prussiate of potash to
larch, the sap-wood is coloured most when the acetate is introduced
first; but when the prussiate is first introduced, the heart-wood is the
most deeply coloured. Pyrolignite of iron causes a dark-grey colour in
beech, from the action and tannin in the wood on the oxide of iron;
while in larch it merely darkens the natural colour. Most of the tints,
especially those caused by the prussiates of iron and copper, are
improved by the exposure to light, and the richest colours are produced
when the process is carried out rapidly.
=Imitation Ebony.=--Take half a gallon of strong vinegar, one pound of
extract of logwood, a quarter of a pound of copperas, two ounces of
China blue, and one ounce of nut-gall. Put these into an iron pot, and
boil them over a slow fire till they are well dissolved. When cool, the
mixture is ready for use. Add a gill of iron filings steeped in vinegar.
The above makes a perfect jet black, equal to the best black ebony. A
very good black is obtained by a solution of sulphate of copper and
nitric acid; when dry, the work should have a coat of strong logwood
stain.
=Imitation Oak.=--To imitate old oak, the process known as "fumigating"
is the best. This is produced by two ounces of American potash and two
ounces of pearlash mixed together in a vessel containing one quart of
hot water.
Another method is by dissolving a lump of bichromate of potash in warm
water; the tint can be varied by adding more water. This is best done
out of doors in a good light. Very often in sending for bichromate of
potash a mistake is made, and chromate of potash is procured instead;
this is of a yellow colour, and will not answer the purpose. The
bichromate of potash is the most powerful, and is of a red colour. A
solution of asphaltum in spirits of turpentine is frequently used to
darken new oak which is intended for painter's varnish, or a coating
of boiled oil.
Another method of imitating new oak upon any of the inferior
light-coloured woods is to give the surface a coat of Stephens's
satin-wood stain, and to draw a soft graining-comb gently over it, and
when the streaky appearance is thus produced a camel-hair pencil should
be taken and the veins formed with white stain. This is made by
digesting three-quarters of an ounce of flake white (subnitrate of
bismuth), and about an ounce of isinglass in two gills of boiling water;
it can be made thinner by adding more water, or can be slightly tinted
if desired.
Proficients in staining and imitating can make American ash so like oak
that experienced judges are frequently deceived, the vein and shade of
the spurious wood looking nearly as natural as the genuine. After the
veining is done, it should be coated with white hard varnish, made
rather thin by adding more spirits, after which the ground can be
delicately darkened if required.
=Imitation Satin-wood.=--Take methylated spirits one quart, ground
turmeric three ounces, powdered gamboge one and a-half ounces. This
mixture should be steeped to its full strength, and then strained
through fine muslin, when it will be ready for use. Apply with a sponge,
and give two coats; when dry, glass-paper down with fine old paper. This
makes a good imitation for inside work. By the addition of a little
dragon's blood an orange tint can be produced. A yellow colour can also
be given to wood by boiling hot solutions of turmeric, Persian berries,
fustic, etc. but the colour is very fugitive. A more permanent colour
results from nitric acid, and last of all by the successive introduction
of acetate of lead and chromate of potash. Sulphate of iron also stains
wood of a yellowish colour when used as a preservative agent, so much
so, that the use of corrosive sublimate is recommended for this purpose
when it is desirable to preserve the light colour.
=A Blue Stain.=--This dye can be obtained by dissolving East Indian
indigo in arsenious acid, which will give a dark blue. A lighter blue
can be obtained by hot solutions of indigo, of sulphate of copper, and
by the successive introduction of pyrolignite of iron and prussiate of
potash.
=A Green Stain.=--Dissolve one ounce of Roman vitriol in a quart of
boiling water, to which is added one ounce of pearlash; the mixture
should then be forcibly agitated, and a small quantity of pulverised
yellow arsenic stirred in. A green is also the result of successive
formations in the pores of the wood of a blue and a yellow as above
indicated, and by a hot solution of acetate of copper in water. A
yellowish green may be obtained by the action of copper salts on the red
prussiate of potash.
=A Purple Stain.=--Boil one pound of logwood chips in three quarts of
water, until the full strength is obtained; then add four ounces of
pearlash and two ounces of powdered indigo. When these ingredients are
thoroughly dissolved, it is ready for use, either hot or cold. A purple
is also obtained by a boiling hot solution of logwood and Brazil-wood,
one pound of the former and one quarter of a pound of the latter to a
gallon of water.
=A Red Stain.=--Methylated spirits one quart, Brazil-wood three ounces,
dragon's blood half an ounce, cochineal half an ounce, saffron one
ounce. Steep the whole to its full strength, and strain. A red can also
be produced by macerating red-sanders in rectified spirits of naphtha.
An orange-red colour may be obtained by the successive action of
bichloride of mercury and iodide of potash, madder, and ammoniacal
solutions of carmine.
=Imitation Purple-wood Stain.=--Grind a piece of green copperas on
coarse glass-paper, and mix with polish coloured with red-sanders. This
makes a capital purple stain, and is used by French cabinet-makers.
These dyestuffs may be much improved by the addition of a mordant
applied after they are dry; this will greatly assist in modifying and
fixing the tints and shades which the dyes impart. The best thing for
the purpose, in the writer's opinion, is clear ox-gall, which, besides
being useful as a mordant, will destroy all unctuous matter.
=Chemicals used in Staining.=--It may perhaps be useful here to give the
common or popular names of the chemicals employed in the operations of
staining and imitating, as few polishers know them by the scientific
names used by chemists:--
Nitric acid is but another phrase for aquafortis.
Sulphuric acid, for oil of vitriol.
Ammonia, for spirits of hartshorn.
Sulphate of magnesia, for Epsom salts.
Nitrate of potass, for sal prunelle.
Chlorine, for aqua regia.
Sulphate of copper, for blue vitriol.
Subborate of soda, for borax.
Superoxalate of potass, for salts of sorrel.
Hydrochlorate of ammonia, for sal ammoniac.
Subnitrate of bismuth, for flake white.
Acetic acid, for vinegar.
Acetate of lead, for sugar of lead.
Sulphate of lime, for gypsum.
Carbonate of potass, for pearlash.
Bitartrate of potass, for cream of tartar.
Nitrate of silver, for lunar caustic.
Supercarbonate of iron, for plumbago.
Cyanide of iron, for Prussian blue.
Subacetate of copper, for common verdigris.
Susquecarbonate of ammonia, for sal volatile.
Alcohol, for pure spirit.
Sulphate of iron, for green copperas.
Sulphate of zinc, for white copperas.
=Process of Staining.=--The natural qualities of woods are very
variable; so also are the textures of the different sorts usually used
for staining. It will be readily perceived that there is no fixed
principle upon which certain peculiar tints or shades can be produced
with any degree of certainty. In order to arrive at the best results,
the stainer is recommended to observe the following rules:--
All dry stuffs are best reduced to powder, when it is possible, before
macerating or dissolving them.
All liquids should be strained or filtered before use.
The requisite ingredients should always be tested before a free use is
made of them, as the effect produced by a coat of stain cannot be
accurately ascertained until it is thoroughly dry.
Amateurs in staining had far better coat twice or thrice with a weak
stain than apply a strong one; for if too dark a tint is first obtained
it is often irremediable. Flat surfaces will take stain more evenly if a
small portion of linseed-oil is first wiped over, well rubbed off, and
allowed to dry, then lightly papered down with fine glass-paper. End-way
wood which is of a spongy nature should first have a coat of thin
varnish, and when dry well glass-papered off. For applying stain a flat
hog-hair tool is the best; and for a softener-down a badger-hair tool is
used. For mahogany shades and tints a mottler will be found of service,
as will also a soft piece of Turkey sponge. For oak, the usual steel
graining-comb is employed for the streaking, and for veining badger
sash-tools and sable pencils.
=Ready-made Wood Stains.=--There are numerous stains suitable for common
work in the market obtainable at a small cost by residents in London,
but it is cheaper for those who reside in country towns to make their
own, if only a small quantity is required. The principal makers of wood
stains are H. C. Stephens, of 191, Aldersgate-street, E.C., and Jackson,
213, Union-street, Southwark, S.E. These makers prepare stains in a
liquid state, and also in powders for oak, walnut, mahogany, satin-wood,
ebony, and rosewood. The powders are sold in packages at 8s. per lb. or
1s. for two ounces, and are soluble in boiling water. Judson, of 77,
Southwark-street, S.E., makes a mahogany powder in sixpenny packets, and
any reliable oilman will sell a good black stain at 8d. per quart, or a
superior black stain at 1s. 2d. per quart. Fox, of 109, Bethnal
Green-road, also prepares stains in a liquid state.