I read a while ago about this material to be good for future cheap and light mirror making:
http://www.pmcguild.com/pmc.html
"Precious Metal Clay, PMC, is an exciting material developed and patented in the 1990s by Mitsubishi Materials of Japan. Microscopic particles of silver are mixed with a moist binder to create a material that has the feel and working properties of modeling clay. Using simple tools, objects are easily given shape, texture, and character. After air-drying, the objects are heated to temperatures approaching the melting point of the metal, where the particles fuse together to make a dense, fully metallic object. Fired PMC work can be polished, soldered, enameled, and enjoyed like any other silver item. PMC is available in three different versions of silver and in a 22k gold alloy."
bob