Tonight I tried brass in the microwave crucible project. As with previous attempts using the propane foundry, it blew out a ton of zinc oxide, but less so, maybe because the top insulation prevents as much oxygen getting in. I can't find my big industrial copper waste so I'm melting brass cartridges. I collect lead off the road while biking and trade it with my work buddy for timed out reloads.
When I lift the top insulation off the whole crucible flares up with a yellow flame. That's the zinc burning.
Here's a little brass ingot, not much to show, but still ok given the circumstances. 14 minutes in the microwave.
Here's how it looks when I pull it out of the microwave. I think I need to at least double the insulation thickness.
Aluminum and brass. The brass process is extremely lossy. I'll use a borax flux next time to try to reduce the oxidation.
What's super cool and I'd love to video (but this needs both hands right now) is that when I pour the brass, it's surrounded by a vivid lemon yellow flame as zinc burns off.
@mavica_again It is very scifi.
It's also dumping a ton of zinc into the air I'm breathing, so I need to do something about that, like move this outside.