Making your own composite parts: looking for tips

[tcj103]

This year our team scored some pre-preg carbon fiber material that was destined for the dumpster. We're operating on a shoe-string budget, and we're looking at ways to make sandwich-style components. We're thinking lightweight panels for either protection, or ramps, if needed.

This stuff already has the epoxy mixed in, (pre-preg is short for pre-impregnated with resin) and the epoxy must be cured at 250 deg F. So our core material must be able to handle that. You basic sheet insulation from home supply stores melts below this temperature, though I've found some stuff from Dow that can take 250, but some quick toaster-oven tests show that it might deform.

Does anyone know of a cheap, high temp core material, that could take 300 deg F or so?

Thanks
Ted