I use an old cell phone charger. It plugs in to a standard wall
socket and has dc output at 12 volts and about .5 amps. I use copper
sulfate (aka Root Kill) for copper, brass, bronze and nickel silver.
I use cupric nitrate for sterling silver and fine silver. In both
case, I mix 100 gr into 500ml of distilled water.
Etching time and depth seems to vary based on the surface area of
the anode and the cathode (what is being etched) and the distance
For the copper/brass/bronze/nickel silver etching, the copper will
be deposited on the anode. For the sterling silver/fine silver, the
silver precipitates out and falls to the bottom.