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Friday, 23 September 2011

Willow strikes a pose

I have just spent the last few days with little Willow, a tiny Manchester terrier, who came to have her portrait sculpted in clay, for a bronze.

Here are some pictures of Willow and the sculpture in clay. I'll post another picture of the bronze and of the casting process when ready.

Ok so here are the steps of the casting process:

Ingredients needed:
Runny silicon and catalyst (Find at Tiranti on warren street)
Putty Silicon and catalyst (Tiranti)
Casting plaster (Find at Travis Perkins- get the same plaster you use for cornicing)
Casting wax (Tiranti)

Step 1: Make a tray out of clay to catch any drips.

Step 2: Mix the runny silicon with the correct amount of catalyst and pour over the clay starting from the highest point.

  Step 3: Blow on the silicon to make sure it has entered into all the nooks and crannies. Leave to dry over night.
Step 4: Repeat step one and two and leave to dry again. Then remove any drips once hard with a knife.

Step 5: Take the putty Silicon and mix with the catalyst. Then using your hands push small pieces about 1 ½ cm thick all over the form.
Step 6: Decide where your seam will be, you must be careful when you choose this that you do not have any undercuts. I.e. you must be able to remove the silicon and plaster mould without breaking any of the cast form. Then using the putty silicon make a wall around where you have chosen the seam.

Step 7: Make a clay wall around the seam.
Step 8: Mix your plaster in a clean bowl. First pour the water then gently spoon the plaster on top. Do not mix until you have added enough plaster that it forms a peak in the water. Once you mix you can no add any more plaster or you will get air bubbles in the form.

Step 9: Sprinkle some of the runny plaster onto one side of the mould then wait for the rest to start to harden before pasting on the rest creating a wall around the silicon of about 2 inches.
Step 10: Remove the clay wall and before it has hardened using a tsp carve out some keys into the plaster so that the two sides can lock into each other. Smooth down the mould all over so you are not left with spiky bits.

Step 11: Glaze the inside of the plaster wall with some clay slip or Vaseline. This is so you can part the mould easily.

Step 12:  Repeat the process on the other side

Step 13: When you have the complete mould you need to crack it open using a flat-headed chizzle. The sides should part easily to uncover the silicon.
Step 14: With a Stanley knife cut through the middle of the seam and open the silicon.
Step 15: Remove the clay and clean the silicon mould under the tap so it is spotless.
Step 16: you now have a silicon mould that you can use to cast a wax version of the sculpture that you can then use for bronzing and the lost wax technique. You can also use this mould for casting in resin and plaster.

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