Here’s my finished second mask, painted and varnished!
Bob II, as he’s called, was cast in liquid latex in a Platsil Gel 25 mould.
Contrary to popular belief, it’s perfectly possible to cast liquid latex into silicone, but there are some things to be aware of:
- As there’s no porous plaster mould to absorb the liquid latex’s water, it will take a long time to cure and dry. Bob II took a whole 48 hours in a well-ventilated room. I left it in my work area over night with the window closed, and there was very little change to the curing process by morning – keeping the window kept things moving along.
- Smaller areas, and areas where the latex has been applied more thickly, will take longer to cure… So, whilst the main body of the mask is fine, you can peer into those horns and see that the latex is still a very obvious white. It will cure. Just leave it be. Don’t be tempted to look; you’ll separate cured latex from non-cured… although this can give you some nice severed horns with suitably ragged edges. Just be careful!
- The liquid latex won’t work with silicone with the dwell method of casting. Since there’s no plaster, you won’t get a skin forming around your negative. It’ll just sit there. Instead:
- Get your liquid latex and add some latex thickener – check instructions on the bottle for the right amounts, as too much will just slow the curing process even more.
- Pour this latex into your mould, but don’t worry about filling it up to the top. Just use a decent amount so that you can slush the latex around in the mould. Swish it around so that it gets to cover every part of the mould, then drain it into a pot.
- Leave it thirty seconds.
- Drain it again into the pot. What we’re looking to avoid is pooled latex, which will cure much more slowly. You don’t need to worry about it being a very thin coat. Just be aware of it gathering, and try to drain it. If it does pool in areas that are hard to drain, or there are areas that refuse to be coated, don’t worry. For the pools, use a cotton bud and gently spread the latex out. Don’t push the the latex so that it touches your negative, as this will drag on any latex skin and mush up the detail you’ve spent so much time sculpting.
- Leave it 5 – 10 minutes. You’ll most likely see gaps in the latex, where the material’s surface tension has pulled the latex away from the underlying silicone. Don’t fret! Leaving the latex for those few minute will have started the curing process a little. It’ll be thicker, but still soft, so don’t touch it!
- Repeat the process of swishing with liquid latex, sloshing it around so that everything’s covered. My castings have been fine at this point. Those gaps in the latex have disappeared, and everything’s been covered.
- Drain back into the pot and leave for another while – 15-20 minutes.
- Repeat the process 3 – 5 more times. You won’t really be able to gauge how thick the latex is but, as long as you’ve not sloshed it around the edges of your positive too much, it should be nice and thin there, and thick enough on the rest of your mask.
- You’ll need it thin around the edges to blend the mask into your skin – I haven’t blended the mask at all in the picture, it’s just sat on my melon.
- You might get ridges that do appear to be thinly covered, just dip a cotton bud in latex and lightly drag the bud over them. This will cover them to your satisfaction, though you might need to repeat the process a few times.
- Very thin areas on the interior of the mask (away from the edges) will tear much more easily when you remove it from the mould.
- Leave the mask overnight, and carry out a quick visual check the next day.
- The edges of the mask might start lifting away from the silicone. Lightly dust these edges with baby powder to stop the latex sticking to itself if these edges start dipping inwards/ folding over.
- The mask is ready to remove when all the whiteness has vanished. Brush the inside with baby powder again, and gently tease the mask out of the mould, limiting how much you pull. I’ve found teasing it out and lightly brushing at any stress points with a large, soft makeup brush that’s been dusted with baby powder helps a great deal – again, it stops the latex sticking, and the bristles will help detach the latex from the mould in a very gently fashion. Work with the shape of the mask, not against it, and don’t hurry! Take your time!
A Quick Note on Painting and Varnishing
I used acrylic paints in an airbrush, thinned with acrylic thinner for air brushes. You can use water as well, but that tends to make it much thinner, and getting that particular mix right is difficult. If you spray with it being too fluid, it’s easier to get unwanted spatters.
I didn’t bother sealing the mask first, which is fine, but there’s another note for caution. If you don’t seal it and your airbrush is at a higher pressure, it will blast into the mask, creating little tears and open bubble formations. You can choose to seal with a 50/50 mixture of Prosaide (a medical-grade adhesive) and water. Apply this gently with a sponge, to prevent unwanted stippling and brush strokes on your mask.
The finished paint job will need sealing, as although the acrylics will stick, if you accidentally scratch them, they will peel. The acrylics will also be liable to damage by UV light, making the colours fade over time.
Varnishing works to solve this. Both Liquitex and Golden make varnishes for acrylics, in both matt and gloss. Just make sure you get one that sets to transparency. They’ll make your colours really pop, keep your paint safe from scratches and stop them fading.
Bob II was varnished with Golden Polymer Medium (Gloss) in a thin layer.
You can clean your brush with plain water if it’s still wet, too – bonus!