This is so cool I've always wanted to try casting things. I've even got to the point of getting some plasticine mold stuff that you can use to shape around your creation to make things from (Not as high tech as this more go to Michaels for craft supplies varitey) but I made a few silver pieces with a mold once, but it was pushing in plasticSilver Clay, it was fun but a lot of work.
RE: Investment casting. Redoing a millennia old production process.