Art Metalwork Chapter 6 Cont.

FINISHES FOR BRASS ONLY

The foregoing recipes are for copper and brass where so stated
and the following are for brass only :
No. 1. To obtain a dark antique finish on brass apply butter
of antimony to the brass and allow it to dry.
No. 2. A steel blue color can be produced on brass by immersing in the following solution : sodium hyposulphite, 4 ounces ; acetate of lead, 2 ounces; water, 2 quarts. This solution is used hot. Various colors can be obtained by varying the degree of heat and the time of immersion.
No. 3. To dull brass apply with a brush the following solution 12 parts hydrochloric acid, 1 part ferric oxide. Apply with a brush.
No. 4. A slightly different result may be obtained by adding to the above recipe one part of white arsenic.

No. 5. A solution for coloring brass steel gray: dissolve 4 ounces of muriate of arsenic in 2 quarts of water and immerse the articles.
No. 6. The so-called Flemish gray on brass is obtained by dipping in the following solution: muriatic acid, 1/2 ounce; white arsenic, 1/4 ounce; potassium sulpluret, 6 grains; water, 2 gallons, Mix the arsenic in the acid, add the water, then the potassium.
No. 7. Brown to red shades for brass: dissolve 8 ounces nitrate of iron and 8 ounces of hyposulphite of soda in 2 quarts of water.
No. 8. Black to brown shades for brass: dissolve 3 ounces nitrate of iron and 2 ounces perchloride of iron in 3 quarts of water.
No. 9. For a golden bronze color on brass: dissolve: 3 pounds nitrate of potash in 2 quarts of sulphuric acid, then add 2 gills of nitric acid and 2 gills of hydrochloric acid.
No. 10. For a bright green: dissolve 1/2 pound sal ammoniac and 1/2 pound sulphate of copper in 2 quarts of boiling water. Apply with a stiff brush and allow to dry.
No. 11. A duller green can be produced by dissolving 4 ounces sulphate of copper in 2 quarts of boiling water. Immerse the articles and allow them to dry.
No. 12. Still another method is to immerse the articles in a hot solution consisting of hyposulphite of soda, 4 ounces; nickel salts, 4 ounces; water, 2 quarts. After immersion in the solution dip the articles in clean boiling water.
No. 13. There is one very interesting method of coloring brass that has no distinctive name, and that is to copper plate the brass and then to polish off the copper plate on the high spots leaving the copper plate in the background, and then to lacquer the work. This makes a very effective finish and is one that is not commonly known. The method is as follows : mix together 1/2 pint sulphuric acid and 2 pints of water; add 1 tablespoonful sulphate of copper crystals. After the piece of brass work has been thoroly cleaned, wind around it a, piece of thin iron wire or a narrow strip of sheet iron, and place in the solution for about 15 minutes.  This will copper plate the article. Dry with a cloth, polish all in one direction with a piece of smooth emery cloth, and lacquer and wax. If the solution gets worn out put in more sulphate of copper.
There is an interesting chemical fact in connection with this kind of copper plating, and that is that the sulphate of copper is simply copper in another form, suspended in the solution, but the iron displaces or precipitates it and deposits it on the copper, or upon any piece of iron that is held in the solution. This is a practical application of the "electromotive series" of chemistry in which the metals are arranged) as follows: magnesium, aluminum, manganese, zinc, chromium, cadmium, iron, cobalt, nickel, tin, lead, hydrogen, arsenic, copper, antimony, bismuth, mercury, silver, platinum, gold.   Each metal displaces from a solution those following it in the series, and is displaced by those preceding it. Iron precedes copper in the foregoing series; therefore it displaces copper from solution.

FINISHES FOR SILVER

To oxidize silver any of the following may be used :
No. 1. Dissolve in 1 pint of water I cubic inch of sulphide of potassium, and apply to the silver.
No. 2. Slightly warm the silver article and apply hyposulphuret of ammonium.
No. 3. Dissolve a pinch of chloride of platinum in a cupful of warm water and apply to the silver. The disadvantage of this recipe is that any platinum compound is very expensive.
No. 4. Place the silver in a small closed box with a piece of sulphide of potassium.
No. 5. Dissolve a pinch of barium sulphide in a cupful of warm water. Apply to the silver.
No. 6. Dissolve a punch of ammonium sulphide in a cupful of warm water, and apply to the silver.
When using any of the above solutions to color silver, if the color is not dark enough add more of the chemical and if it is too dark weaken by adding water. To clean silver that is tarnished dip in a solution of 1 1/2 pounds of cyanide of potassium dissolved in 1 gallon of water.
Aluminum can be cleaned by immersing in a solution of caustic soda. To frost aluminum dissolve 2 ounces of caustic soda in I pint of water.   A formula for blackening or oxidizing aluminum is as follows: chloride of zinc, 1 pound; sulphate of copper, I ounce; hot water, 2 quarts. Dip the articles in the solution. If the metal does not turn black fast enough, add a little more sulphate of copper.
As a last word of advice on the coloring of any metal, be sure that the chemicals are fresh, as almost all of the chemicals used in coloring deteriorate with age or exposure to the air.

LACQUERING AND WAXING

Lacquer serves on metal the same purpose that varnish does on wood; that is, preserves the color and the finish. The commercial lacquers are rather expensive and are not always easy to obtain.
No. 1. Banana oil, sometimes called bronzing liquid, makes a fairly good lacquer for our purpose, and it has the decided advantage of being obtainable in almost any drug store.
No. 2. A fair lacquer can be made from white shellac and grain alcohol mixed together in the proportion of 5 ounces of white shellac to 2 quarts of grain alcohol Allow the mixture to stand for about 48 hours, then strain thru a double thickness of cheese cloth, and it is ready for use.
No. 3. Another lacquer is made up of the following : alcohol, 2 quarts; seed-lac, 5 ounces; gum copal, 1/2 ounce. Allow the mixture to stand, stirring occasionally until the seed-lac and the gum are dissolved, then strain thru cheese cloth.
No. 4. Collodion thinned down with grain alcohol also makes a good lacquer.
No. 5. A gold colored lacquer for brass only is made of the following : spirits of wine, 2 quarts ; tumeric, 6 ounces ; gamboge, 1/2 ounce; sandarac resin, 12 ounces; shellac, 4 ounces; turpentine resin, 5 ounces. Allow the ingredients to dissolve and strain.
No. 6. Another good lacquer for brass or copper: I part of spirits of wine; mastic resin, 8 ounces; gum camphor, 6 ounces; sandarac resin, 1 pound; white shellac, 1 pound. Allow the mixture to dissolve and strain.

FINISHING WITH WAX

The best method of wax finishing is to heat the article hot enough just to melt the wax as it is applied with a cloth, then lightly and rapidly apply the wax to the metal. Allow it to get perfectly cold, then polish lightly with a soft cloth. The best wax to use is Johnson's black furniture wax, altho a good wax can be made by melting together equal amounts of beeswax and turpentine. Naphtha may be used in place of the turpentine.
Metal articles may be refinished by applying a thin coat of any of the above waxes applied cold.

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