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RVTOY

Well Known Member
I'm going to make some foam template molds to be fiberglass over and want something easy to work with. I'm assuming glueing various sizes together to make compound curves. Hobby store? Aicraft spruce is around the corner?:confused:
 
Brown urethane from Aircraft Spruce is good for shaping, carving, etc. It is used extensively building a canard airplane.
 
RVTOY said:
I'm going to make some foam template molds to be fiberglass over and want something easy to work with. I'm assuming glueing various sizes together to make compound curves. Hobby store? Aicraft spruce is around the corner?:confused:
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I've bought small pieces of green foam at a hobby store. It would be expensive if you needed to make anything big.
 
Surfing, USA...

No problem in your location.

Just find out where the local store is that provides foam for surfboards. :)
 
Gil has a great idea but last time I purchased a blank (the un carved foam board before fiberglassing) it was very expensive. Also, most blanks are curved so it might be difficult to stack up if shaping something large.

Won't the blue or pink foam from Lowes or Home Depot work? Just wondering as I have seen people use this stuff in pictures here on VAF.
 
Been shaping foam all day on a project. I bought Owens Corning Formular at the local Home Depot. They sell it in 2' x 2' sheets, it is 1" thick, and is pink in color. I'm pretty sure it is the same stuff Bill R mentions above just from a different vendor. Cut it with one of those disposable utility knives and shape it with 80 grit sandpaper on a block. I glued three layers together to get a thicker block. I've used this stuff before and it worked just fine.
 
Stay away from the expanding spray stuff. It is way too spongy and flexible. Blue or pink insulation works fine and is cheap.
 
To glue multiple layers together, mix up some epoxy and micro balloon mix and use that as your glue. I would drive some stiff metal rods through the stack to keep it lined up and then remove them before shaping.
 
N941WR said:
The foam can be removed with gas or acetone after the fiberglass hardens.
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Acetone will also dissolve the epoxy (although somewhat slowly - note in Vans instructions for pinholes, they thin the epoxy with acetone), so gasoline is a better choice.

Greg
 
Acetone will only disolve uncured epoxy. It won't touch cured epoxy. Not much will. I have melted out foam with it many times.
 
If the part is thick Dow FB (flotation billets) work great; it's the blue foam Canardians use to hot wire flying surfaces from. Available in 8x14 and 8x24 billets. Normally 8' long but I've found them 4' long too. Avgas eats this foam, so it's "easy"(sort of) to remove the foam after your layups are complete. Available at AS, but there's a Dow distributor in LA that sells FB's for about 50% of Spruce's prices.

Edit - Spruce has this foam in many sizes: http://www.aircraftspruce.com/catalog/cmpages/polystyrene.php
 
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