First clean off with alcohol, polish the surface to an even finish, making sure that grease or finger marks are removed. Then immerse in a solution of one ounce of arsenic chloride to one pint of water until the desired color is obtained. Wash in clean, warm water, dry in boxwood sawdust, warm, lacquer with a thin pale solution of bleached shellac in methyl alcohol, using a broad camel's hair brush.
Donald A. Hampson.
Middletown, N. Y.
A suitable solution for bluing brass is prepared by dissolving 1 ounce of antimony chloride in 20 ounces of water and adding 3 ounces of pure hydrochloric acid. Any amount of solution may be made up, provided the different ingredients are in the above proportion. To apply, place the warmed brass article into the solution until it has turned blue. Then remove it and wash with clean water, after which dry in sawdust. T. E. O'Donnell.
To tin brass or copper melt 5 pounds of tin and pour same into a tank containing one ounce of cream of tartar in about 8 gallons of water. This must be done a drop at a time to subdivide the tin so as to give a larger surface for the cream of tartar to act upon, and have the bottom of tank covered with tin. Then put a fire under the tank and place parts to be tinned in the tank and let them boil for about one hour, or until they are coated sufficiently. H. C.
To apply a copper coating on brass for laying out purposes, apply the ordinary copper solution in the same manner as used on iron or steel. Then, while the brass is still wet with this solution, cover the entire surface with a thin layer of fine cast iron dust from the drill press. Brush off the cast iron dust, and the surface will have a nice copper coating. C. S.
A bright dip for brass, copper and bronze may be produced as follows: Make a solution of 100 parts by weight of nitric acid, 50 parts sulphuric acid, 1 part soot, and 1 part salt. The salt and soot make the dip work smoothly. The article should be dipped in this solution, well washed, and dried in sawdust to prevent streaking.
Bridgeport, Conn. S. II. Sweet.
A receipt which I have found very successful for coating zinc or tin sheets black for templet work, is the following, taken from Brown & Sharpe's book on gearing, page 85:
"Dissolve 1 ounce of sulphate of copper (blue vitriol) in about 4 ounces of water, and add about one-half teaspoonful of nitric acid. Apply a thin coating with a piece of waste." Alex. C. Labar.
Put together, into a glass, 1 ounce silver, made thin, and cut into strips, 2 ounces best nitric acid, and ½ ounce clean rainwater. If the solution does not begin to act at once, add a little more water, and continue to add a very little at a, time until it does. In the event that it starts off well, but stops, before the silver is dissolved, it generally may be started up again by adding a little more water. When the solution is entirely effected, add one quart of warm rain water and a large tablespoonful of table salt. Shake well and let settle; then proceed to pour off and wash through other waters. When no longer acid to the taste, put in 1 1/8 ounce cyanuret potassa and a quart pure rain water. After standing about twenty-four hours it will be ready for use.
St. Louis, Mo. Samuel Strobel.