This is a ring I cast for the wife using the "Lost Wax" process. I had to force the metal into the mold with a steam assist. Steam provides a lot of force, the bottom failed in the mold(blew right out) & i was lucky to salvage one ring in the set of 4 I had "tree'd" up & invested. my best investment so far is 50% plaster of paris 30% 100 mesh silica sand & 20% 200 mesh silica (flint from the ceramics store). mixing plaster is also a skill in itself.