Saw a "how to" in one of the impot car mags (the one about the small "B" sized cars - Siphon?)

they make a fill by spraying in a "2 part foam" and then carving the foam and then laying foil over the foam and then pulling the mold from that.

Anyone know what kind of foam they are talking about and where to get it?

Is it just "great stuff" from the hardware store?

 

you could even use styrofoam.

get a hot cutter and cut it to shape then do the above like they were talking about

but im not totally sure. the enclosures i know of usually have a wooden frame and they wrap it in fleece then fiberglass it.