Hey all,
the two part polyurethane foam will be fine, but try a little block with
your resin before you do major shaping job. (my background says styrene foam
(refrig packing) melts in solvent, urethane foam doesn't, but maybe your
product is a different mixed beast) What does result is a rough inner
surface, which for the smooth air flow is NOT what you want. One trick I
have seen is to gently brush the outside with softened paraffin wax,
available in the canning/preserve section in the the store. This gives a
nice surface you can further smooth if you want, and easy release later.
(also creates a barrier layer so that you can lay-up polyester resin on
styrene foams) There are simple techniques for getting a split (2-pc) airbox
off a single buck, but I won't bore the masses (probably too late) with the
details. Contact me off list if you are interested.
Fergus O
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