I had intended to post some casting pics when I was doing the zombie mask but didn’t quite get round to it, so I thought I’d do it here. The sculpture was done over the same head as the zombie mask:
The two halves of the mold are placed over the ‘core’.
Silicon will flow through the mold within the cavity between the core and the outer pieces of the mold.
The two halves of the mold are then bolted together and ‘bleed holes’ are drilled. These will allow air to escape the mold as the silicon is injected so that air bubble do not form.
The molds then turned upside down and a large syringe which I made out of drain pipe is inserted into a cavity within the core. The silicon flows into the mold through the top of the head and up through the interior. The bleed holes are blocked off with blobs of clay as the silicon reaches them.
Once the silicon’s set the mold is cracked open. Here’re some pics of the silicon cast fresh out of the mold and also with a coat of flesh coloured paint. It doesn’t look quite so orange in real life, think it’s the flash that’s done that!
The painting’s not finished but I’m quite pleased with how this has turned out so far. Painting silicon is abit of a pain and it’s only recently that I figured out how to do it – there’s very little info out there detailing this. The only thing that sticks to silicon is silicon, nothing else will adhere, so if you use any type of regular paint it will either not dry or flake off once it has. You therefore need to actually paint the silicon with silicon. You can’t actually buy silicon paint (well that’s not technically true – there is one company that I know of that does it, but it’s quite expensive) so what you need to do is mix a pigment with silicon and use that as your paint.
I’ve found the best way to do this is to use silicon bathroom sealant mixed with oil paints and thinned with white spirit. As the bathroom sealant cures it will chemically bond with the rubber making your pigment part of the piece.
This works well with the silicon I’m using as they’re both tin based silicons. Some silicons such as Platsil, which is used extensively in the FX industry, are platinum based so I’ll need to experiment to see if this method will work with those.