Can you give me a formulation for the electropolishing of gold particularly 14- and 18-karat gold? J.J.
I am not aware of any formulations that are completely reliable. However, one formulation that has been used in the jewelry business is as follows:
Potassium cyanide 65 g/liter
Phosphoric acid 18 g/liter
Sodium potassium tartrate 15 g/liter
Ammonium hydroxide 2.5 mL/liter
A voltage of 8 –10 volts and a temperature of 50–60°C should be used. Great care should be exercised with this process in that a large amount of gold can be removed in a short period of time.
In any event, some experimentation will be required to get the results you are looking for.