Beside these so called "bright dips" there is another class of dips that are handled in the same way, but give a slightly different result. These are called "satin dips." They are very similar to the bright dips, but in addition.they give the work a slightly granulated effect that is known as satin finish. This satin finish may also be obtained by the use of a satin finish wire brush on a lathe revolving at high speed. Some of the acid satin finish dips are are as follows:
No. 1. Hydrofluoric acid, 1 pint, Water, 3 pints.
No. 2. Hydrofluoric acid, 2 pints, Nitric acid, 1 pint, Muriatic acid, one-half pint, Water, 5 pints.
No. 3. Hydrofluoric acid, 1 pint, Nitric acid, one half pint, Water, 5 pints.
No. 4. Hydrochloric acid, 1 pint, Sulphuric acid, 6 pints, Water, 6 pints.
Immerse the brass in the solution for about 1/2 hour. THE ORMOLU DIP
There is still one other acid dip that is very useful when finishing art metalwork, the "ormolu dip." This dip gives to brass a golden yellow color, and is commonly used on commercial goods to imitate gold finishes. It is prepared as follows:
No. 1. Nitric acid, 2 pints,
Hydrofluoric acid, 2 pints,
Zinc scraps, 2 ounces. No. 2. Sulphuric acid, 2 quarts,
Water, one-fourth pint,
Nitre, 3 pounds,
Add slowly to above solution
Muriatic acid, 1 quart.
As hydrofluoric acid will dissolve glass or crockery, any solution that has hydrofluoric acid in it should be kept in a jar that has been painted thoroly on the inside with Sapolin or asphaltum varnish.
After any one of the preceding bright satin or ormolu dips has been used on art metalwork, the work should be immediately dried and lacquered by dipping in banana oil, or it should be warmed and coated with a thin coating of Johnson's black furniture wax, and then lightly polished with a soft cloth when it is cold.