Using printed molds with heat-cured LSR


While I have had good success molding parts in printed molds with RTV rubbers, I have a need to experiment with molding with heat-cured LSR, which requires a thermal profile of 302F for 5 minutes. Can the fully cured resin handle these temperatures?


@ChristopherBarr - nope, I’ve experimented with heat accelerated curing of RTVs - and found that 60decC (about 150F) was about the maximum that cured molds could handle before issues - and another experiment with a silicone that was supposed to be cured at 100C was a total failure.

I’ve had success with an RTV curing 20 minutes at 75degC. Perfect results. 300F seems an awful lot.

I’m talking about production-grade LSR - not RTV. I’m using RTV silicones now.

Yup - well at 100c the resin de-laminates and cracks fairly dramatically, and I found that I was getting peeling flake issues at around 75c too - although I was leaving it in the oven for more than 20 mins.

That said - that was with the old V1 resins - so perhaps the new ones are hardier - even so I can’t see them holding up long enough to get the mold contents to ~150c/300f

You could just try out a test piece - the resin is not that expensive…

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