Molding the Walnut...
For our 3rd practical lecture we looked into making silicon molds and resin casts. This process can be cheap and costly and can produce hollow, flat or completely solid casts.
1) Dowling can be drilled into the base or most practical place to allow complete coverage of the structure in silicon and to pick up as much detail. In this case it was a walnut.
2) Stick dowling end onto your plastic base using a glue gun.
3) With another four squares of the same plastic create a box like structure, ensuring the box is only as big as it needs to be to reduce using too much unwanted silicon cast. Plastic weld is used to fuse the sides and base together. You can use a hot glue to reinforce any seams and fuse any potential leaking spots.
4) Mixing the silicon is a 10:1 ratio. E.g. if you used 200g of silicon, you’ll need to mix 20g of hardener with it!
5) Stir until equal consistency. Draw air bubbles out using a vacuum degassing machine.
6) Pour “degassed” silicon mixture into box starting at the corners and sides to prevent/reduce new air bubbles forming.
7) Resin ratio is 50/50 or 1:1 to make final amount. E.g. If you wanted a final mixture of 100g you’d used 20g of part A and 50g of part B.
8) When your silicon mold has hardened and ready you’ll need to cut through to the middle to relieve the original structure (the walnut). Make a jagged cut (rather like a jigsaw piece, so mold can always be placed together correctly). Create an air bubble for the gasses that need to escape during casting. Ready you silicon mold and pour resin into your pour hole- made with the dowling drilled into the structure at the beginning.
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