Making a mold for a pack

I’m planning on making a GB fan film soon, which of course means I will need at least 3 proton packs. If I were to construct one straight out, would I be able to make a mold for the others without worrying about damaging my original?

Also, I’ve never made a silicone mold before and I was hoping someone here would know of a website I could go to that would kinda walk me through the process.

Here check out this on Proptopia:

http://www.proptopia.com/viewtopic.php?t=992&start=40

I ended up destroying my master in the process and other people have too in the past but Venkman71’s new method (which he demonstrates in that thread) should preserve your master.

-Eric