Friday, 23 April 2010

Hippo Brief - Making Moulds

To make the mould:
  1. Cut scrap vinamold into chunks and place in the pot to melt.
  2. Take the object you are casting, and place it on a wooden board.
  3. Roll out some clay into large, long sheets 2-3cm thick and build a wall around your object with 2cm or so either side. Reinforce the base of the walls with extra clay and smooth over any cracks or holes.
  4. When the vinamold has fully melted pour the liquid into the casing you've built, being careful to pour slowly and not directly onto the object inside.
  5. When the vinamold has set remove the clay.
  6. Using rolled out strips of clay build a small wall lengthways across the top and sides of the mould.
  7. Mix a thick plaster solution and layer onto one half of the mold, pressing right up to the clay wall.
  8. Apply a layer of hessian to bind it and add more clay.
  9. Smooth off the top of the plaster to create a flat surface.
  10. Remove clay wall, make a small bowl shape from a piece of clay, add a little water and use a paintbrush to mix a thick clay-paint.
  11. Liberally paint the edges of the plaster jacket - this will act as a release agent when constructing the second half.
  12. Repeat steps 7-9 on the remaining half of the mold.
  13. When dry, turn upside down and separate both halves of the jacket, then remove the original object from the vinamold.

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