Stormtrooper Molds

[davidthepirate]

I'm in the planning stages of vacu-forming my own Stormtrooper costume. I've already got the vacuum forming machine built and ready to go. I am in the process of making molds for the armor pieces, but it is slow going. not to mention I have little space to work in. I was ondering if I could use a wooden frame and hard foam to sculpt the rough shape, then cover it with plaster and mmake the fine details with that? will the plaster and foam hold up to the heat/pressure of the vacuum forming machine. the machine uses a 5hp motor for the vacuum. Could i use the foam/plaster to create a negative mold, then use another material to make a stronger mold?
Here is the process i was talking about with the foam and plaster:
Volpin Props: Helm of Yngol, Skyrim

Thanks for looking!

 

[XRobots]

It would probably work, but it depends how thick the plaster is and how flexible the foam is. Why not try a sample piece and see how well it works. I've used solid plaster moulds in the past which were fine.

 

[Idaho Jones]

Would bondo give you a stronger shell for that method?

 

[davidthepirate]

I'm not sure what kind or where to find rigid foam. What kind can i use for modeling? i heard insulation foam but I can't find any online so I'll be headed down to the local hardware store later. Could I use floral foam, or would that break down as i sculp it? Bondo would be strong enough to use as a shell, I would think. Is it easy enough to sand and shape for finer details?