This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
Very pretty and artistic effects of silver or nickel inlay on bronze, copper, Etc., or copper on dark oxidized metals, may be obtained by means of etching and electroplating.
The metal on which the inlay is to be used is first covered with a thin coating of wax and the design scratched through to the metal with a sharp, hard point of some kind. The design is then etched in slowly with well diluted nitric acid, allowing the etching to penetrate quite deeply. The metal is then taken out and after A thorough rinsing in water is hung in the plating bath.
As the wax has been left on, the plating will fill the lines of the design only, and will not touch the covered surface. When the etched lines are filled, the object is taken out of the bath and the wax removed. - Contributed by S. V. Cooke, Hamilton, Can.