I attempted my first copper etching w/ muriatic acid / hydrogen
peroxide. The etch came out great, however the copper is all
discolored and mottled. Is this normal? I haven't tried to pickle
it, which is what it looks like it needs. ?
Trish, that look is about what one would expect, though it can vary
with the type and strength of the acid used. But pickle won't help.
Pickling removes oxides.
The metal is not oxidized. You're simply seeing the somewhat porous
and rough (on a microscopic scale) surface. Clean it up with a soft
brass brush, or very fine steel wool (gently. It doesn't take much)
You're just needing to lightly burnish the metal to get it back to
looking like copper.