How to make easy "form fitting" molds... (2 Viewers)

[Captkronos]

Sorry for the delayed response guys. I get bismuth from rotometals.com , it is comparable to tin in price, with a melt temp around 160 F. I've read that at the molecular level it actually will allow lead and tin to melt at lower temps, which allows me to pour them into 400 F rated silicon without mold damage. I also add iron oxide powder to my silicon for added heat resistance. Seems like a perfect formula so far. Yes, bismuth can make things too brittle, and also lose some detail compared to tin. Good ole' solder wire is hard to beat, but that stuff is like $20 a pound these days. I should invest in tin apparently. For 10 lb of metal, I would personally probably have half of that as bismuth, but you could probably get by with half of that and still get the benefits of lowered melting temp and flow.