Hi.
There are quieet a few out there, will look for them again as I haven't bookmarked them.
Granted most of them deal with Figure Kits, most of them will also list a number of suppliers. I assume you are talking 2-part molds.
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Just found a page that might suit you:
http://www.hirstarts.com/moldmake/moldmaking.html
Doing basic molds and casting is not too difficult, doing it well takes a LOT of practice. You will end up with a quiet a few problem areas initally:
1.) Air-bubbles
2.) Flash
3.) Incorrect mixed Silicon Rubber or Resin.
4.) Shrinkage.
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