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Old 05-25-2010, 02:03 PM   #3 (permalink)
Otto
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Quote:
Originally Posted by TomO View Post
From personal experience on the front bumper of my car using Great Stuff: I would've liked to use sheet foam since it was cured already and can be shaped just as easily as cured Great Stuff.

I waited 24 hours after applying the Great stuff so it would fully cure (as per the instructions on the can) but the foam still expanded more after I had started working on it, causing some unwanted cracking.

For my summer bumper project I'm going to use sheet foam since it won't expand on me.
Any idea what Great Stuff will NOT stick to?

I may use the inside surface of my old steel header panel as a female mold, spray Great Stuff in and let it expand/cure completely, then pull out. That way, I get the exact contour of the panel, at least the portion of the panel with the contour I want.

Also, if I knew what chemical barrier (PVA is used to keep epoxy from sticking to fiberglass molds, so something like that would work) would keep Great Stuff from sticking, I could cover the outside of my fenders or whatever with it, for an instant and exact female mold* of the part, then use that for fiberglass layup to make duplicates.

So, again, any idea what Great Stuff will NOT stick to?


*Might be cheaper if we had a good chemical barrier to apply it to the original part, take it to a foam contractor insulating a house, and have him spray it. That would take him about 5 seconds and the small amount of foam would be insignificant to his house insulation job.
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