An overly simplified explanation is that a mold is made from wax, usually common bees wax, in the shape of the desired finished product. The metal or other liquid media (glass, plastic, denture material, etc.) is then poured into the wax mold. In the process the waz "dissolves" and one is left with the molded object. Again, this is greatly simplified as there are numerous, intricate methods of achieving the end results....
LOST wax!!!! That's it. Thank you Clanad. They look AMAZING! When you say 'the mould is made from wax, I presume that they sculpt using something else, make the mould from this, then use this mould to make the wax, then 'lose' the wax. I saw it with glass. Amazing!
Exactly right, MargeB... I should have added the support structure for the wax is usually metal and requires venting... it's quite a complicated process, but apparently dates to 2500 years ago or so...