3188. Puscher's Solution for Coloring Metals

3188. Puscher's Solution for Coloring Metals. This is a new method of giving metals a durable colored coating, and can be executed quickly and cheaply. To prepare the solution dissolve 11/2 ounces hyposulphite of soda in 1 pound water, and add l1/2 ounces acetate of lead dissolved in 1/2 pound of water. "When this clear solution is heated to 190° to 210° Fahr., it decomposes slowly, and precipitates sulphide of lead in brown flocks. If metal is now immersed in it a part of the sulphide of lead is deposited thereon, and according to the length of time and consequent thickness of the deposited sulphide of lead, the various and beautiful lustre colors are produced. In 5 minutes there may be imparted to brass articles a color varying from a beautiful gold to a copper red; then carmine red; then dark, then light aniline blue, to a blue white, like sulphide of lead; and at last a reddish white, according to the length of time they remain 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 produce an even coloring, the articles to be colored must be evenly heated.

Iron treated with this solution takes a steel blue 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 be added to the hyposulphite of soda, and the process carried on as before, the brass is covered with a very beautiful red, which is followed by a green, 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. (See No. 3313 (To Color Metals).)

Very beautiful marbleized designs can be produced by using a lead solution thickened with gum tragacanth on brass which has been heated to 210° Fahr., and afterwards treated by the usual solution of sulphide of lead. The solution may be used several times, and is not liable to spontaneous change.