Copper / brass ingots?

So I've got a bunch of old copper and brass scraps (and some stainless steel) knocking around my desk. I've wanted to make a nice copper ring with a half-dome profile with my rolling mill, I understand the only way to do that will be starting with a cylindrical ingot then forming it.

Looked at furnaces and crucibles and all that stuff, but I can't find clear information on whether, say, the Rio Grande melting furnace is going to hit the temps required. Or whether my acetylene air system will either. On spec just by melting point they *should* work, but I know there can be a difference between just melting the metal and getting it to flow into a mold.

Anyone out there making ingots out of metals other than silver and gold? Would love and appreciate any tips!