If your talking about cactus juice for the resin, it has to be heated to over 200 degrees for a few hours for the resin to harden. If you buy a 1/2 gallon container or up he sends the catalyst separate for you to mix when you want to use it so that might be what people are talking about... And just like Larry said I would use a thick chunk of foam for a seal, or like you said a rubber gasket, I think either will work...