Castable Rubber?

[ikdor]

PU comes in many many variants. Real rubber is a nuisance to mix.

[RB211]

So I'll probably need a pressure pot and a vacuum pot? Vacuum pot to suck air out when you mix A+B, and a pressure pot for pouring it into the mold?

[psomero]

smooth-on makes exactly what you're looking for. I have done overmolding onto aluminum with 3d printed and cnc machined molds. add mechanical undercut or media blast your surfaces to promote adhesion, and on the things you don't want to stick (the mold side) use lots of silicone mold release.

you don't absolutely need to vac it, but it really helps degas and get all those bubbles out.

I believe we used the vytaflex or brush-on stuff in around 40-60A with very good results. Didn't personally do the pours, but we've done it at two different companies making custom wheels for mobile robots.

[psomero]

we used to do vac the compound, pour, then put it in a vacuum chamber to cure in molds. never used pressure

[RB211]

Ok, thank you.