Making a clay mold............

I want to make a FEM-MANDO chest mold for my wife and was wondering what type of clay to use. Also, I want to box it in and pour silicone over it so I can cast it.
I can't find NOTHING to my liking so I want to give this a try.

What I really need to know is ......."Do I need to put a release agent on the clay before I pour the silicone over it?" and if I do, what do I use ?

Thanks,
-Tim-

If you are using GI-1000 (Blue) Silicone then a release isn't needed because it's not resistant to Water.(If you use a Green Roma Plastilina with Sulphur in it then you will have a problem).

The cheapest clay to use is WED and depending on where you live, there are various suppliers.

If I'm sculpting a quick sculpt and don't have a big budget for the project I'll use WED Clay, it's fast an easy.

If you want to make the sculpt almost perfect and give it a machine Smooth finish then I suggest that you use Chavant clay (That's what Robocop was sculpted out of).

Chavant does have a website, just do a google search to find it.

Thanks Propsculpter
-Tim-

kay so I pour the silicone over my sculpt. I make sure to put locks and keys in... what are they made of? I want to work in fiberglass will I pour it directly in or put in the cloth then the goop? will fiberglass need a release agent? The female breast plate thing intrigues me too but from a stormtrooper stand point. I just want to get the process down before I fully commit to a project.