In the February 1926 issue of The Watch Word, the Elgin National Watch Company described the process used at the factory to manufacture metal dials.
[Continued from the previous post]
“In the case of the silver finish on metal dials, the silver solution is made by placing nitrate of silver in distilled water and stirring automatically with a copper stir. The silver solution ultimately absorbs the copper from the stir. The water is drained off and the material dried, leaving a silver powder, which is mixed with a much larger quantity of table salt. This table salt is ground very fine because the grain of the finish of the dial depends entirely upon how finely the salt is ground. The brass surface of the dial is treated to a solution of mercury and salt to give it a thin coating, then the salt and silver powder is brushed on in machines, the operator being called upon to judge the right amount. This powder adheres to the surface. When this operation has been completed, the surface of the dial is “cloudy,” and the dial is then brushed with cream of tartar powder to clean and whiten it. Then the dial goes to the stamping job for further operations.
In the case of fancy designs on metal dials, some are stamped on in drop presses, some are cut by hand graver, and the moire or brocade (which is a deep cut fancy design) and the engine-turn (which is a surface cut fancy design) are done on special machines.”February 1926 issue of The Watch Word