Anyone mold silicone or urethane?

I just bought some pieces of nitrile rubber on Amazon since I had a gift card. Going to see how easy it is to cut it. I think it would be easy to cut as long as I have a clear way to mark the rubber and a SHARP knife!!

 

Yes, you're over thinking the whole thing. None of those dimensions are critical. The gasket could overhang on the inside and outside and there would be no difference, the holes could easily be 3/16" or more and the gasket would still seal.

You could clamp the gasket in plywood, mark the holes on the wood and use a drill(press) to drill them. The outside of the gasket could be trimmed off once it's screwed down on the box.

 

Agreed, plus you could make a template with a raised edge, so it's used as a die, stamping these puppies out like cookies.

 

Great ideas...I bought some 1/8" thick sheet of nitrile on amazon. Was able to cut it with a dull knife, so going to upgrade to a sharp one hahaha and it drills easily too. Looks prmising and will save money about 12 bucks per gasket.