Well, there has been no activity on this thread for a while, but I'll try anyway... I'm making a Perfectly-as-humanly-possible M6 Magnum from Halo: Reach out of plexiglass sheeting. It's just about finished and it is by far the best prop I have ever made. As soon as it is finished I wanted to make a mold from it and pop them out like crazy. So far as I can tell the best mold making rubber would be : http://www.smooth-on.com/Silicone-Rubber-an/c2_1113_1136/index.html?catdepth=1 OOMOO 25 - Trial Size Medium softness easy to use tin cure silicone rubber - Shore 25A hardness. 1:1 mix ratio by volume - no scale or vacuum required. 75 minute cure time. Net Weight : 2.8 Lbs. $25.47 This is my first time doing this sort of thing. Whenever anyone tries to do something new, they dont want to make any mistakes. Since I dont have a ton of money, I make it a point not to make any mistakes. I've done tons of research and have read and watched just about everything possible to learn. The last thing to do, is to actually do it. However, I got an idea about making the mold "cheaper." I dont know if it will work though... Does anyone know if it would be possible to use: http://www.smooth-on.com/Rigid-and-Flexible/c10_1121/index.html?catdepth=1 FlexFoam-iT! V - Trial Size 5-lb. Flexible Polyurethane Foam. 1A:1B By Volume Mix Ratio - No Scale Required Net Weight : 2 Lbs. $25.96 instead of using the OOMOO. It expands into something like 20x the amount actually used. Do you see where I'm going? Would it be possible to make a mold from FlexFoam? 1 oz would technically be 20oz (in size, not weight) It puffs up and hardens, BUT it is flexible so I would imagine that it could be used as a mold. Thanks for reading! Any suggestions would gladly be taken.