This is cool but for people without access to all the tools, a much easier way is to just upload your design to Shapeways.com and let them take care of all the casting. (https://www.shapeways.com/materials/gold)

You can also have your design done in brass first for relatively cheap, to validate the design.

I made our wedding rings that way, as well as quite a bit of jewelry over the years for my spouse. (pendants, earrings, etc...)