Sealing porous foam??

JHZR2

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I’m working on cleaning up surface rust in my 91 300D. That’s documented elsewhere on this site.

The cause of issues seems to be that for whatever reason, moisture trapped in the little well where the foam clamshell that holds a vacuum pump that operates door locks lives. The clamshell was kind of stuck to the metal, paint failed, surface rust under.

The foam clamshell looks like this:

5F259385-EC22-451A-8C99-20DAEEA3DA8F.webp
0E967E88-E9A3-4797-AC72-A5D1B254846B.webp


I kind of want to “seal” the bottom so this foam doesn’t hold water near the metal. Granted my repair I think is pretty robust, but I’d kind of like to “seal” the porosity on the bottom.

I was thinking maybe to just spray paint it. Not sure though. Any recommendations?
 
I think someone gave me a can of flex seal as a gag. If I have it I’ll put it to use.
 
Flex Seal will melt the foam.
You might try shellac. It's old school sealer and the solvent is alcohol, so shouldn't affect the foam.
I remember those foam fillers in my '92 300D 2.5 Turbo.
 
I have never used this, but was searching for something you could use.

Its a water based latex mold product. Air dries. So i would not think it would damage or melt the foam.

$12 16oz

Another idea , is several coats of exterior latex paint, but its so thin, it might not add much structural integrity to the foam. And being thin, would it adhere?

https://www.amazon.com/Viscosity-Natural-Liquid-Latex-Making/dp/B071DDQHM6/ref=sr_1_15

1653710769034.png
 
Last edited by a moderator:
Flex Seal will melt the foam.
You might try shellac. It's old school sealer and the solvent is alcohol, so shouldn't affect the foam.
I remember those foam fillers in my '92 300D 2.5 Turbo.
I have flex tape actually, so the solvents are not an issue.

doesnt shellac break down if wet?
 
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