I did buy a can once, and used it to coat the steel and aluminum framework supporting the batteries in my golf cart. Bought it on a whim at my local Ace hardware, instead of automotive undercoating.
Mine was clear, so it wouldn't matter if it extended even 1/8in to 1/4 in beyond...
It's just the the surfaces I covered with it were small little angle irons so i didn't get a feel for how well it covers on a larger surface like you did.
I actually think that it's better if it doesn't have much compressibility, but with a high resiliency. The high compression and low resiliency of the foam gasket is what is causing the failures in the first place.....
I'm guessing that this stuff would give a fairly hard surface with resilience that we need if it cures to a flat smooth surface. Oh it needs to adhere very well so it doesn't leak from behind/under...
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