Now that my bronzes have arrived safely I’ve started on making the glass section of the sculpture, its in wax at the moment, and I’ve decided to make a latex mould of it in case anything happens to it in the casting process. Once the latex mould is finished I can use it to make wax copies of that shape.
The first step in the process, is to paint two layers of latex directly onto the wax, letting them dry thoroughly between each layer. Then mix the latex with latex gel thickener- follow the instructions on the packaging. I get my latex from Tirant.co.uk. They recommend mixing their latex in a proportion of 10 parts latex to 1 part thickener. Do a few more layers of that until if feels good.
Now here’s where I went a bit rogue, and other ‘proper’ artists might find this a bit distasteful. I needed the little shapes that recede into the wax to hold their shape firm enough so they could stand on their own and if I needed to pour another wax in the wouldn’t cave, or bend with the pressure of the wax pouring in. But I also needed them to be flexible enough to squish when I pulled them out because there are some undercuts in the shape. I looked into a soft foam mixture that I could pour into it, but it seemed quite expensive for the little bit that I needed and I didn’t know if it would work. So I just decided to stuff the shapes with cotton wool and tape them in with packing tape, I did a couple layers of this with more cotton wadding and tape and made the shape as much of a smooth hemisphere as I could. Then painted a couple more layers of the latex and gel thickener, to get the overall mould to a good thickness. Then I just put tape over the latex to reinforce it and also it’s kind of ‘grippy’ and I wanted the outside to be able to slip in and out of the plaster mould easily.
Then I carefully pulled the latex off the mould and it worked a charm.
With the wax safely removed from the latex mould I will then make a plaster/quartz mould around it, melt the wax out, and put it in the kiln to melt the glass in. And this is where its a bit tricky, as you can see from the pictures, there are negative stalactite shapes poking in to the wax, and where the mould fills these shapes it will be quite fragile. Not only that but the mould in that area needs to be made quite soft, as the piece cools down in the kiln the glass will shrink around that shape and if it’s stiffer than the glass it will cause the glass to crack. Thus the mould in this area will be even more fragile, and in the past when I have attempted this, the tips of the stalactites have broken off.
I will keep you posted on my progress. Wish me luck!