What and where to foam

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OrangeQuest

Re: What and where to foam

Post by OrangeQuest » Wed Aug 08, 2018 6:54 pm

My theory on that Fallguy is the flex crushes the foam cells enough that they keep their shape but break open enough to become sponges. And as it soaks up more water and more flexing the water slowly soaks in but can't get out very fast when squeezed and because it can't be compressed more cells break open. After a while it causes a chain reaction and more and more water is held in the foam.
Hope that makes sense.
Seems if there was a film/plastic sheeting around the foam where water can't get to it then it would hold up. A lot of times foam is used in high flex areas and it's not made to be part of the structure. Just like weak joints that are not taped well or have air trapped under the seams and a little flex causes the joint to crack every time it flexes allowing water to get in and then the flex breaks the foam.

Put the foam in a shoe box and then stand on it a few times, start twisting it and after awhile you will have crumbled foam that can't displace any water.



fallguy1000
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Re: What and where to foam

Post by fallguy1000 » Thu Aug 09, 2018 10:46 am

Foams have improved. My guess is lots.

My foam is dry, but here in Mn we have very arid conditions in winter and she sits out. Probably dries up good in the fall and fully dry in winter.
My boat build is here -------->

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narfi
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Re: What and where to foam

Post by narfi » Thu Aug 09, 2018 11:19 am

I asked him more about it yesterday, as installed he said all faces of the foam were cut and not sealed.

Its dry here, esp in the winter. People not used to it often get bloody noses. But nothing drys out in the winter, it freezes till spring.

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cape man
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Re: What and where to foam

Post by cape man » Thu Aug 09, 2018 11:40 am

I cut the top faces off of my foam where it swelled above the stringers and bulkheads and did not seal it either. It is true closed-cell foam, so the only cells that are open are the layer I cut. That will not make the rest of the foam, starting with the next cell down, absorb water.

Today's closed-cell, pourable foam, is a much different product than the older stuff.

You guys are over thinking this way too much.
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OrangeQuest

Re: What and where to foam

Post by OrangeQuest » Thu Aug 09, 2018 1:10 pm

When I foamed the area under my tank wells I had to sand the tops down too but I used a chip brush and put neat epoxy over it.

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jacquesmm
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Re: What and where to foam

Post by jacquesmm » Thu Aug 09, 2018 1:18 pm

cape man wrote:
Thu Aug 09, 2018 11:40 am
I cut the top faces off of my foam where it swelled above the stringers and bulkheads and did not seal it either. It is true closed-cell foam, so the only cells that are open are the layer I cut. That will not make the rest of the foam, starting with the next cell down, absorb water.

Today's closed-cell, pourable foam, is a much different product than the older stuff.

You guys are over thinking this way too much.
Correct. Even if you leave the "cells open", it will not make any difference.
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narfi
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Re: What and where to foam

Post by narfi » Thu Aug 09, 2018 1:48 pm


Correct. Even if you leave the "cells open", it will not make any difference.
You are the boss :)
That will save me money in epoxy then, thanks!

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cape man
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Re: What and where to foam

Post by cape man » Thu Aug 09, 2018 4:59 pm

Plus all that Narfi...following your build and I'll bet a good six pack (highest bet I make) there will never be water under that deck unless you smash into a rock (or ice berg in your case).
The world always seems brighter when you've just made something that wasn't there before - Neil Gaiman

OrangeQuest

Re: What and where to foam

Post by OrangeQuest » Thu Aug 09, 2018 5:14 pm

cape man wrote:
Thu Aug 09, 2018 4:59 pm
Plus all that Narfi...following your build and I'll bet a good six pack (highest bet I make) there will never be water under that deck unless you smash into a rock (or ice berg in your case).
That has happened and the boat sank!!! 8O They even made a movie of it happening!

:lol:

OrangeQuest

Re: What and where to foam

Post by OrangeQuest » Thu Aug 09, 2018 5:27 pm

So the foam holds up even when sanded, cut and so on. So where my chase tubes and drain tubes run through the frames I don't need to seal those holes up because I will be adding foam to those compartments?

Where they ran under my tank wells I add the foam and where the foam was forced out of the openings the tubes ran through I trimmed the foam flush with the frames and then coated with neat epoxy, later to be painted in the bilge and lockers. Where I needed access to my tank well drain fittings I blocked an area off with pool noodles wrapped in plastic and then pulled out the noodles, the foam is exposed to the bilge and any water that may get in there, no worries?
3403

The other side of the green noodles is the bilge.

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