Re: rubber molding?
Marduk,
There is also the latex kits that you can obtain from film and production supply houses. They are a two-part mix with a very small percentage being the catalyst. You'd need both a scale for measuring that (powder scale) as well as a vacuum pump for degassing the mix before you use it. And you want to degass, otherwise it could turn out saturated with bubbles, like an aero bar.
As for the Castaldo products, they are mixed 50/50, and don't "need" to be degassed. But they most definitely work better when they are subjected to a vacuum chamber. The ones I've worked with, anyways.
Latex starts out "flesh" pink, and are tintable. The Castaldo I've used is clear. If that matters, also.
Back on track?
--forgot to add, the latex we've used here, is the "smooth-on". We bought that from a movie-supply house.