lördag 28 januari 2012

step 4, character number 1; sculpting and moulding the beak.

Starting with sculpting the beak to the head cast of my model Rolf, using chavant clay, which is an oil based clay that is good to work with since it does not dry out.

Chavant can be tricky to work with for a start, since it behaves completely different to water based clay, it is much firmer and it can be quite difficult to get it smooth, a good idea is to heat it up with a hairdryer when sculpting. The hairdryer makes the chavant melt and get smoother for a while. You can also heat it up with your hands and body temperature..

For the texture of the beak I used an orange, which makes it very much like a rough skin to its texture. I really like this effect.

When the beak is ready as a sculpt it is time to make a negative mould of it, which I will then brush the latex into.

To make the mould I lay the headcast with the beak down, using a pillow covered in plastic.

I then build up a clay wall around the beak to prevent the plaster from running down the edges of the head cast. Remember that plaster sticks to plaster, and you don’t want to ruin the head cast. Cover all surfaces that will be exposed to plaster with clay, or release agent.

When the clay wall is done, making sure it is strong enough to keep the weight of the plaster, it is time to make the mould.

Starting with mixing the plaster, using Tiranti's prestia plaster, which is perfect for making moulds. The plaster is mixed with cold water, and slowly sprinkled in until it creates "islands" on the surface of the water. Then mixing it carefully by hand, removing all lumps until the plaster is completely smooth, like a single cream to its consistent.

Then I add the plaster by hand to the beak, carefully catching all of the details. Building it up layer by layer.

When the plaster is starting to set, you can almost sculpt with it, allowing to build up the thickness of the mould, the thicker the better to prevent it from cracking.

Once it is about 7 cm thick all over, I leave it to set over night.

One important thing to know about plaster is that it gets extremely hot when it is setting, accidents has occurred when people have had their hands in setting plaster and lost their fingers, so be careful once it is starting to increase in heat.

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