OK so now I have the mold ready it’s time to cast a bust in plaster of Paris.
When I first made a cast I was surprised at how time-consuming the whole process was. I’d imagined just sloshing in the wet plaster, letting it set, taking the hardened model out of the mold and then just pouring another one. Although those are the main steps, and that works fine for casting ornaments or rough objects, it turned out that the precision needed for an artwork translated into a very slow and fiddly process with days of repair work at the end shaving off imperfections and filling holes left by tiny air bubbles.
I realised that casting a life-sized bust in a two-part mold would be trickier than just an open-backed relief. I couldn’t find instructions for this on the Internet.
- Do I put the halves of the mold together and fill it up from underneath?
- Or do I cast two halves and then stick them together?
Well, I ended up needing to use both methods to get a finished product and this is what I’ve described below.