Sealing Closed Cell Foam Flotation

walnutknot

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Apr 2, 2024
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What is the preferred paint (I am confused, some say Water Base Some say Oil Base) to seal closed cell flotation foam after it has been allowed to cure and trimmed out . I removed all the old water logged foam and replace it. It's trimmed out now and seeking advice. Found this site to be the most helpful.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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its closed cell. trim it off, slap the deck over it and go from there.
 

cyclops222

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Mar 21, 2024
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Is the Closed Cell Foam rated to be used with E 10 gasoline ? If yes ? You are done.
 

mr 88

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Nov 3, 2010
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2,179
If you could " seal " closed cell foam ,Boston Whaler would of been using that method the day it was discovered. The cells break down when they are constantly being pounded through the hull . Probably 95% of the Whalers built have wet foam ,doesn't stop them.from being used and abused .
 

Berdink

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Mar 5, 2020
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235
And even if it needed sealing, if water somehow penetrated, it would be a misery for it to dry out again.
 

tpenfield

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Not sure there is a prescribed method or paint, but if you have filled the chambers in a hull and cut off the excess foam, you could slap a coating of resin on the foam before laying the deck down.

Often folks fill the chambers in the hull AFTER the deck is laid down (via access holes in the deck) so there is no cutting of the foam.

If you are foaming in a fuel tank and cut off the excess foam around the perimeter . . . I have used polyurethane paint to seal the cut surfaces. . . takes a couple of coats to get a good enough seal.

Many boat manufacturers don't bother with sealing the foam, as the issues of water penetration won't cause problems for a good 10-15 years. 🤪
 
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