I Need A Shrink !

[SBD]

I have built lots of things using blue household foam insulation. It is very inexpensive, easy to form using a Surform, and crazy strong with just a few laminations over it. It has been used for many structural applications including all Rutan aircraft. It is only compatible with epoxy however, ester will turn it into napalm.

I would consider bonding it to the inside and skinning it.