> Those don't scale down well to desktop size.

If you're going to smelt aluminium on your desktop you're definitely going to want three phase power into your house, and probably some sort of asbestos tile to put it on.

Probably quite a good extractor fan too, Shake'n'Vac isn't going to shift that odour.

We made some commemorative coins from lead, melted in a microwave oven & poured into silicone mold. The mold was created from a 3D printed mandrel.