[TheForge] 'lost foam'

[James Binnion]

Most people with 3D printers do not have photopolymer resin-type printers, which can give high-quality direct burn-out resin parts. However, they do require an understanding of the proper curing and burnout procedures to get good results. Instead, they have filament-type printers. You can burn PLA filament out like lost wax-type casting, but the surface quality and resolution are nowhere as good as the photopolymer resin-type prints. That said, for many projects, the filament-type models are useable.  You need to be aware filament prints can be porous, so you must ensure that the prints are well-sealed for best results. Wax or shellac can be used to seal the prints. 

Here is a simple instruction for Lost PLA casting https://www.instructables.com/3D-Printed-Lost-PLA-Investment-Casting-Aluminium/



As for casting Zamak 12, it is a zinc, aluminum, and copper alloy that melts at 811F. It is normally cast via die casting into steel molds or sand cast. There is no reason one could not cast into investment molds, I have cast Zamak 5 into investment molds so Zamak 12 should be fine. Mold temperatures must be low enough to avoid keeping the metal liquid too long maybe 400 F. max


Jim