Blue's mask project - Charley Hall
Mould and sculpt

Mould and sculpt

The sculpt and the negative silicone mould together! My step by step guide does not cover any of the fibreglassing process, mostly because I didn't take any photos of it and it's been done by other people already.
You can see someone else's better photos of the moulding process here: http://thomasotom.deviantart.com/art/Immortan-Joe-s-Mask-Moulding-3-489181097
The mould itself is one piece tin silicone (with some thixotropic), with a two-part fibreglass jacket.
The original sculpt is partially destroyed when I remove it, so I threw it away.