foam question

i plan to use foam to make my external tank. i looked through the forums and came across U.S. Composite's 2 part foam. (yes, i am aware that accurate measuring is required) what can i use to create a mold for the foam?

Unless you plan on making many copies, you'll spend far more time making a plug, then making a mold. I think you would be much better off just turning or carving the tank from a block of urethane or medium density PRB foam.

I suspect you'll have many problems trying to "mold" the 2-part foams...figuring out the right amount to mix, getting it applied evenly throughout the mold halves, joining the molds before the foam expands too much, etc. Not to mention that these 2 part foams are heavy and stick to just about everything (including mold release spray and wax).

I have tried this - I experimented with some Sig 2-part expanding foam years ago to make wing cores for F3B sailplane wings, all I did was make a mess and ruin a nice set of molds. Just my $.02.

I had done a 'twice as Big' scale-up of E's Space shuttle going way-back, and chose to stack up the 1" blue foam, centered the stack on a centering 'jig' of 3/8"th plywood & 1/4" dowels into the foam & chucked the center dowel into a drill in a bench vise & had a poor man's lathe. Use the same 'jig' for both cones, one at a time. I'm looking to revisit this as I want to do a 1/100 scale shuttle full stack. You need to be sure that the glue between the layers stays far enough 'inboard' of the finished exterior surface of the cones. The glue does not sand well at all! Voice of experience!

George Gassaway tipped me off that the Guillow's Space Shuttle catapult launch glider (stocked at Michael's Crafts this time of year!) is close to 1/100th scale.

I'd like to complete a full set of 1/100 manned launch vehicles. Sat. 1B is completed. Saturn V in the closet. Neubauer Rockets' Mercury Redstone, Mercury Atlas & Gemini Titan 1/100 scale are waiting on me... I love it when a plan comes together!