Molding help needed! One piece mold?

[Coz]

So, inspired by Kylash's great work, I sculpted the Torchwood alien cell / trap out of sculpey.
The 'stone' measures about 3" by 2", and is about 1/2" thick.

(Yep, I scorched it. D'oh.)

I'd like to make a one piece mold of this to simplyfy casting, as I really suck at mold making. Looking to use a stone-type casting agent (such as Herculite, or similar with pigment added if possible).

Silicone is the best coice for the mold itself - but how to create the mold? Would like to have the pour hole on the bottom, to save on cleaning up the casting, but would it pour ok?

Any help greatly appreciated.

Coz.

PS- If this is in the wrong section of the forum, I apologise in advance.

 

[bcstanding]

I've done molds using the how-to guides at Alumilite. I'm not sure if that's what you're asking but maybe that page will give you some ideas.

 

[SurferGeek]

If you've ever seen Make magazine before... Adam Savage did a nice one piece, split mold in the latest issue.

 

[quadmasta]

I just got the Thurston James book and it's got TONS of tutorials step by step with pictures. It was $15 I recommend you get it.