On September 1, 2021 8:06:44 PM UTC, "David Lanzendörfer" leviathan@libresilicon.com wrote:
We also talked about the possibility to hack a foundry for melting aluminum cans into a simplistic tube furnace, to which I'm tending more and more, as the time without a furnace passes.
look up Julia Longtin's 3D aluminium casting talk. she uses 2nd hand stainless steel toothbrush cups as crucibles, which, containing carbon, are great for attracting aluminium oxide.
a 2nd hand 2500 watt microwave oven works great. bear in mind she blew up 3 of them (they were 2nd hand)
the use of an industrial / catering microwave turns out to be drastically cheaper than a propane furnace to run, and one hell of a lot quicker (hours rather than days)
julia's talk explains that you need to cut the aluminium into small pieces and start with a clean seed piece, then drop the crap aluminium pieces in one after the other, into the melted blob.
if you chuck all the oxidised pieces in and expect them to melt on their own nothing happens.
the alu oxide sticks to the stainless steel and eventually you have to chuck it out. but that's ok, they are cheap. i mean, toothbrush cup. duh.
l.