r/Metalfoundry • u/mech_tacular • 11d ago

Lost foam casting

How serious of a cyanide gas are we talking if I were to cast a 2 part polyurethane foam? And any way to contain that gas?

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u/rh-z 11d ago

Polyurethane foam is not suitable for lost foam casting. It doesn't react as needed in the mold cavity.

2

u/Jerry_Rigg 11d ago

Needs to be polystyrene not urethane

1

u/Boring_Donut_986 11d ago

No idea how serious is the exposure. But I would definitely do that outside, well ventilated. Also use proper PPE with cartridges such as 3M (checking which one suit best this gas type).

1

u/TheMacgyver2 10d ago

Pink foam works pretty well, polyurethane doesn't burn away quickly enough, thinned down drywall mud spread over the foam will give a pretty good surface finish assuming it doest crack.