Having made moulds for peekaboo egg and small squashy, I demoulded them yesterday and tried pouring hollow waxes. All went much better than I expected, and I now have a wax egg and a squashy with scarcely a hint of casting lines. One of squashy’s feet didn’t come out right, but that’s easily fixed. A bigger problem is that I had the model raised on a piece of clay so that I could get in under the legs, and I ended up with a large air bubble in there, which connects to the casting cavity so that wax flows in. And the egg mould is really a bit thin on top and down some of the cut line. If it were thicker I might be able to make the seam pretty well vanish (thicker silicone is more rigid and holds its shape better), which on a smooth piece like this would be handy. Squashy’s mould was thicker, and the seam is practically invisible.
So: big improvements, but some repairs to do, and possibly remaking. Both models survived demoulding almost unscathed, so I could do the whole process again if I had to — a pain in the arse, but it would be worth it in order to minimise the painstaking, highly annoying work at the wax-finishing stage. The proverbs that keep coming to my mind while I work on these things are “a stitch in time saves nine”, and “for want of a nail”.
If I’d had silicone thickener I could have done a better job on both moulds. I’m heading home for a couple of weeks tonight, so I’ll buy some in Australia if I can take it back on the plane, and save myself the hassle of looking for it here. If I can’t obtain thickener, there’s another way of doing the whole process that will also result in thicker silicone.
Small squashy’s plaster mould around the silicone was in three parts, as I couldn’t eliminate enough undercuts with the silicone and didn’t want to push my luck. I’m happy to say it wasn’t hard to make, and it worked fine. Big squashy is going to need a four or five-part plaster mould.