Adprinter, I forgot about the comment on the MDF. Yes, I was surprised how well it stood up to the heat. It was a Lead Alloy that melts at about 550F, I take it to about 600F to pour. It barely scorched the MDF, I think I could have cast a few more without trouble. If it had failed, I was going to try to cast it with Bismuth. It still has to be about 550F to cast. I wish I could afford some Woods Metal. I just don't have any Cadmium. Woods Metal melts at about 160F, that would be pretty neat to try.
I have had a few failures, metal shooting out between the flask, melted through what I thought was a thin steel plate, turned out to be Tin. That was fun, molten Aluminum everywhere. I want some petrobond for brass, it likes to spit and pop out of greensand. Glad I have good PPE.