5 ms·
No, that's steel, and not with voltage, but with temperature: https://en.wikipedia.org/wiki/Heat_coloring_of_metals https://en.wikipedia.org/wiki/Heat_coloring_
by throw_a_grenade 5mo ago
No, that's steel, and not with voltage, but with temperature: https://en.wikipedia.org/wiki/Heat_coloring_of_metals https://en.wikipedia.org/wiki/Heat_coloring_of_metals. For aluminium, you add dye to third bath.