Will newer "closed cell" foam get waterlogged?

[Bigoledude]

We are gonna be doing some restoration work on a 17 foot Duracraft johnboat we just bought. We will be strengthening the transom, replacing some leaking rivets with stainless bolts. And, I'd like to build some gunwale floatation and pour some foam under the bow deck area because I will almost always have a couple of my grandchildren with me when I take the boat out. Not that I'd like to tread water or drown either.LOL

I've dealt with waterlogged foam on older boats in the past. It was a skull-cramping repair to do! Is there a particular two-part pourable foam that I can buy that will not absorb water?

 

[73Chrysler105]

Re: Will newer "closed cell" foam get waterlogged?

They will all absorb water if kept exposed to it over time. As long as you keep it dry though it won't be an issue.

 

[jigngrub]

Re: Will newer "closed cell" foam get waterlogged?

This:

14. Is this foam water resistant?

Yes, but with the following caveat. The foams that we sell are considered closed-cell, which means that each cell that makes up the foam structure is completely closed off from surrounding cells which prevents it from acting like a sponge. It is completely safe for this foam to be in contact with water for hours/days/weeks and even months with no adverse effects. However, it should never be submerged in contact with water permanently. Over a period of years the water contact can begin to soften the foam and cause it to lose its closed-cell status. This foam is designed primarily to be used as an insurance policy in case of damage/holes that could cause a vessel to lose buoyancy. Pinhole sized openings would essentially have no effect on the foam since the amount of exposure is so minimal but you should always make repairs as soon as possible to keep the foam effectiveness as good as possible. This will be the case with all after market closed-cell polyurethane foams and even manufacturer installed foams.

... is from here:
Frequently Asked Questions - General

... and they have a very good price on their foam:
Urethane Foam , Expanding Marine Polyurethane Foam

Using closed end blind rivets to replace your leaking rivets will be a better build:
1989 Sylvan Boat Rebuild Part 4 - YouTube

 

[chconger]

Re: Will newer "closed cell" foam get waterlogged?

I am racking my brain trying to find this reference; but I researched this only 2 weeks ago and read that extruded polystyrene board (pink, blue) is more water resistant than urethane foam.

That's what I used, but not why.....

Its in my boat because it was free

Cheers

 

[73Chrysler105]

Re: Will newer "closed cell" foam get waterlogged?

I am racking my brain trying to find this reference; but I researched this only 2 weeks ago and read that extruded polystyrene board (pink, blue) is more water resistant than urethane foam.

That's what I used, but not why.....

Its in my boat because it was free

Cheers

It is but its still resistant not proof. nothing is ever categorized as water proof these days though. All watches are water resistant to a specific depth not water proof.

 

[Bondo]

Re: Will newer "closed cell" foam get waterlogged?

I am racking my brain trying to find this reference; but I researched this only 2 weeks ago and read that extruded polystyrene board (pink, blue) is more water resistant than urethane foam.

That's what I used, but not why.....

Its in my boat because it was free

Cheers

Ayuh,.... I think yer Right,.....

Poured foam, relatively speakin', is a sponge compared to the blue/ pink board,...

I've dug the board stuff up from buried underground below the water table, 'n it's still like when it went in the ground,...

The poured foam I've dug outa hulls, Is a Sponge,...

 

[chconger]

Re: Will newer "closed cell" foam get waterlogged?

Yea...the blue stuff I am putting in my boat has been in a dock, in the water, including winter, for 10 years.

As soon as I skim off 1 millimeter of the dirty surface with a hot wire, its like new.

Not a hint of moisture...in any of those old blocks.

Incredible stuff.


Chris