Hi Guys,
I get a lot of questions on the specifics of how to make my molds and how I go about casting etc. I dug out an old link that I think is nescessary reading if you are interested in the craft.
It is not puzzle specific and more for casting large items, but it does give you an overview of some good techniques until I can finish my own article:
http://home.houston.rr.com/dpstudios/workshoppages/molding_casting.htm