New way of Coloring Metals.

Manufacturer and Builder 1, 1874

Metals may be colored quickly and cheaply by forming on their surface a routing of a thin film of a sulphid. So for instance brass articles may be thus in live minutes coated with any color varying from gold to copper red, then to carmine, dark red, and from light anilin blue to a blue white, like sulphite of lead, and at last a reddish white, according to the thickness of the coat, which depends on the length of time the metal remains in the solution used. The colors possess the most beautiful lustre, and if the articles to be colored have been previously thoroughly cleaned by means of acids and alkalies, they adhere so firmly that they may be operated upon by the polishing steel. To prepare the solution dissolve 1 1/3 ounces of hyposulphite of soda in 1 pound of water, and add 1½ ounces of acetate of lead dissolved in 1/3 pound of water. When this clear solution is heated to 190° to 210° Fahr., it decomposes slowly and precipitates sulphite of lead in brown flocks. If metal it now present, a part of the sulphite of lead is deposited thereon, and, according to the thickness of the deposited sulphite of lead, the above-mentioned beautiful lustre colors are produced. To produce an even coloring, the articles must be evenly heated. Iron treated with this solution takes a steelblue color; zinc, a brown color; in the case of copper objects, the first gold color does not appear; lead and zinc are entirely indifferent. If instead of the acetate of lead an equal weight of sulphuric acid is added to the hyposulphite of soda, and the recess carried on as before, the brass is covered with a very beautiful red, which is followed by a green, (which is not in the first-mentioned scale of colors,) and changes finally to a splendid brown with green and red iris-glitter. This last is a very durable coating, and may find special attention in manufactures. Very beautiful marbleized designs can be produeed by using a lead solution thickened with gum tragacanth, on brass which has been heated to 210° Fahr. and is afterward treated by the usual solution of sulphid of lead. The solution may be used several times.

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