diy seal

[K.caseni-Las]

happy new year!
I am planning to do a plaster cast and then fill in some sort of elastic material forming a diy seal for my cock and balls pump-glass jar. What would you use? Silicone dries on the surface first and takes forever to cure all the way. I read somewhere to mix bakingpowder into the silicone??. Any better ideas?
Thanks.

[xzen54321]

I would love to see your mold when done, I think you will want to use a two part curing silicone like this, http://www.amazon.com/Smooth-On-Silicon ... B004BNF3TK.

Please look at tutorials for molding, I know there are issues of mold finish, and using releasing compounds.