I’m pretty sure the
pink stuff I used is polystyrene (and I think Ed or Al mentioned that they used
some as well).
I used urethane foam (tan). Never
used any pink stuff.
If you really want to
make quick work of shaping your cowl get some Urethane foam from you local
roofing supplier or florist
I bought it in 2” thickness and 4’
x 8’ sheet (sheathing) at building supply (Home Depot)
. Also, duct tape
won’t stick to it so you do have to fill the finished shape with Micro or
plaster / drywall mud and then sand that smooth and paint for release before
fiberglassing.
Hum-m-m. Some of the smaller
shapes I made I covered with duct tape and it worked fine. Just vacuumed
the surface to get the loose dust off. On bigger things I coated with
Alpha-poxy slurry, then mold release. But the drywall mud sounds like a
good idea.
Al