Re: 21-23 series rubber sill plates.

Posted by bkazmer On 2014/12/8 11:33:18

I agree the originals were likely compression molded from rubber (although you don't normally use natural latex)compound, probably EPDM or SBR

RIM has the advantage of low cost tooling and cheap press time, but has other issues. Typical injection molding with a thermoplastic (80 SA f-PVC would work well) would certainly make good parts , but the tooling cost for so few parts is the issue. Even with a low cost/low volume tool like Kirksite or aluminum.

So your cast RIM idea is not so bad, really. I think you will need to draw a vacuum on the mold to eliminate the voids.