Casting method for simple shapes.
- Carve shape to be cast using soap or a potatoe. It is also possible to use a plaster shape, but there can be issues with the old and new plaster sticking to each other.
- Mould clay around the form to be cast, reaching halfway up.
- Build a wall (a couple of fingers wide) of the object, and add a bung, which will create a funnel to pour the plaster into the mould later on.
- Create ‘keys’ using end of a thick pencil, these will locate and secure the two sides when pouring the mould. Cover object with petroleum jelly to prevent sticking.
- Pour the plaster to top of wall (which should be higher then the piece you are moulding) and leave to set.
- When set, strip away clay and turn mould over, so that the unmodulated part is uppermost.
- Repeat as before building up a wall, smear plaster part and object with petroleum jelly and then add plaster.
- Leave to set, then remove clay
- Insert two halves together and hold in place with rubber bands – clay could used to prevent any plaster escaping. Support mould end on using clay
- Pour in plaster and rotate mould to get plaster into all the elements of the mould.
- Leave I set and then prise apart with a knife or hammer and chisel.