Gilding, Bronzing, and antiquing copper art metal
APPLYING SILVER SOLUTIONS
There are also some interesting methods of, applying a thin
coat of silver to copper articles, and while this method is not
recommended for very extensive use, still some very good
effects
can be produced by applying the silvering solution to the copper
where a design has been etched or chased and then rubbing with
an old smooth piece of emery cloth, allowing the silver to
remain in the background. The copper must, of course, be perfectly
clean.
- No. 1. With a little water make a paste of nitrate
of silver 80 grains, common salt 40 grains, cream of tartar
7 drachms, and
rub on to the copper.
- No. 2. Another silvering paste is made of chloride of silver,
4 ounces; cream of tartar, 75 ounces; common salt, 10 ounces,
and
water sufficient to form a paste. Keep this paste away from
the light, and apply by rubbing on the copper with a piece of
cloth.
- No. 3. A good silvering fluid is composed of distilled water,
5 ounces; chloride of silver, 7 ounces; potassium oxalate,
10 ounces;
common salt, 30 ounces; chloride of ammonia, 4 ounces. Mix
together and apply by rubbing on the metal with a piece of soft
cloth
- No. 4. Another simple method of silvering copper and brass
is to put one ounce of aquafortis and one ounce of silver scraps
in a crockery dish and set it in a warm place until the silver
is entirely dissolved. Then mix with it enough cream of tartar
to make a thin paste. This paste will silver copper or brass
when rubbed on with a soft cloth.
GILDING AND BRONZING
Copper and brass can be gilded by using the following solution:
distilled water, 1 quart; 6 pennyweights of gold converted into
chloride, potassium bicarbonate, 16 ounces. To prepare this solution
for use, convert the gold into chloride by dissolving it in aqua
regia. Then dissolve in the distilled water, add the potassium
bicarbonate, and allow the solution to simmer over a fire for
about one hour. The articles to be gilded are immersed in the
warm fluid for a few seconds until the desired color is obtained.
Another good recipe for gilding by boiling is cyanide
of potassium, 8 ounces ; chloride of gold, 3 pints ; sal soda,
8 ounces ; water, 1 gallon.
To get a bronze effect on copper, dissolve 3 ounces
of nitrate of iron and 1 ounce of sulphocyanide of potassium in
2 quarts of water, and immerse the articles.
ANTIQUE FINISHES
Another standard method of finishing copper is to give it any of
the many various green finishes that are known on the market
and in the trade as "Antique
Patina," "Verde
antique," ..
Pompel Green," "Green
Patina," etc. The same finish
is often given different names by different manufacturers. Some
of the most reliable of these finishes are as follows:
- No. 1. Copper nitrate, 16 grains; ammonium chloride,
16 grains; cafe]-am chloride, 16 grains; water, 1 ounce. Brush
the solution on the article with a stiff brush and allow it to
dry; if necessary apply a second time, then relieve with emery
cloth, and lacquer or wax.
- No. 2. To obtain a green color on either copper or brass:
ammonia muriate, 1 ounce; ammonia carbonate, 3 ounces; water,
24 ounces.
- No. 3. A popular so-called verde antique finish on copper
and brass is produced by the use of this formula : common salt,
4 ounces; chloride of iron crystals, 1 ounce ; verdigris, 3 ounces;
(Aqua regia is equal parts of nitric acid and muratic acid mixed
together; it is the only solution that will dissolve gold.) sal
ammoniac, 5 ounces; cream of tartar, 2 ounces, water, 1 pint.
Immerse the work in the solution and allow to dry.
- No. 4. For a yellowish green on copper use the following :
copper nitrate, 1 ounce ; sal ammoniac, 1 ounce ; chloride of
calcium, 1 ounce; water, 2 quarts. Apply with a stiff brush and
allow to dry.
- No. 5. For an olive green color on copper and brass :
one part of perchloride of iron and two parts of water
mixed together will give copper or brass a pale or deep
olive green, according to the time that the work is left
in the solution. The work must be immersed and then allowed
to dry.
- No. 6. Another green solution is composed of nitrate of iron,
2 ounces; hyposulphite of soda, ; water, 1 pint.
- No. 7. A good antique green can be obtained by using the
following solution : 1 part sal ammoniac, 3 parts cream
of tartar, 3 parts common salt, 12 parts boiling water,
8 parts cupric nitrate. Apply with a brush and allow to
dry.
- No. 8. If copper or brass is dipped in acetic acid and then
exposed to the fumes of ammonia for a few hours the metal
will acquire a mixture of black, blue, and green colors.
- No. 9. Olive green on copper: 2 parts water, 1 part permuriate
of iron.
- No. 10. A recipe for green coloring that is good on copper,
brass, or bronze is as follows : sal ammoniac, 5 parts
; acetic acid, 10 parts; common salt, 1 part; cream of tartar,
1 part; acetate of copper, 1 part; water, 1 part. Mix thoroly
and apply with stiff brush.
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