ArtMetal

I watched demo several years ago at the Yuma Symposium on Ashanti casting and I believe that is the process you are talking about. It was not teribly complicated and there was some failure risk and not something you would want to do for production work. I do not recall what the exact formula they used for the investment and suspect there may be an internet discussion on the process. I believe the SNAG journal had a write-up on it.

Fred Zweig
Metalsmith