Short, written tutorial [video has more information, this is just a little summary!]:
Chavant NSP Medium
Ease Release 200
EpoxACast 690 Clear
ATTENTION!! Your health and safety should always come first! Please read the safety instructions that come with the materials and follow them!
The basic shape of the gem is cut from clay.
The facets are cut into it and smoothened with water
The silicone is being mixed. Attention! Please follow the safety instructions for working with silicone! Mixing ratio is 1:1 and you’re done mixing once there are no pink or blue stains in the silicone.
Only when all air bubbles have vanished (yet before pot life expires), the silicone is poured in a thin stream from the deepest point of the moldbox.
After 6 hrs the silicone has cured. Before mixing and pouring the resin, I used a release agent. When working with resin, you have to follow the safety instructions and protect your skin, eyes and respiratory system by wearing the necessary protection and working in a well ventilated area! Mixing ratio is 100 parts of epoxy to 30 parts of hardener. Use a kitchen scale to measure, stir carefully so there will be no bubbles, pour carefully.
After 24 hours the epoxy is cured and hard. You can now demold it.