http://www.forrestrace.com/glass-copper/
How to make a mold from a glass vase/hurricane lamp for copper foil stained glass lampshade?
I see really cool shapes of glass bowls and vases that would make for really cool stained glass lampshades. I don’t want to just mosaic glass pieces onto them, I want to make copper foil method lampshades. I can’t use the glass bowls/vases themselves as molds obviously because the glass would crack when I soldered the pieces together. Any ideas on materials to use and how to go about making a mold? Think it can be done?
coat the outside of the object you are molding with some sort of grease or oil (just enough to prevent sticking). Then cast the object in plaster (the quick dry or medium dry at room temperature works best). You may want to cast one side at a time so you can easily get the plaster mold off without breaking the glass. Then once you cast each side put the two sides together, seal them using more plaster, now you have a mold.
Copper Foiling Tools for Stained Glass : Cutting Glass with a Carbide Wheel Cutter