Just one other thing you need to be aware of.
some of the copper foil may have greese on it due to the milling process and
little people's hands. Then the india ink will not stick to the surface very
well but will puddle and flake off.
I know this sounds toxic, but I spray the pieces with amonia water and dry
them before the kids ink them. I do this before I leave so the fumes won't
disturb anyone. This way I know the pieces are clean even for HSers.
I do metal repousee' with box and solder construction in jewelry class. Very