Foam Below Floor

[DJ]

I read a post from I believe 12 footer regarding foam in the floor and keeping the "shell" intact. My current restoration is aluminum thus completely encapsulating the foam is impossible and it looks a little rough. I've always done glass boats before and never worried about it because it was enclosed.<br />Does this stuff attract and hold water once the "crust" is broken?

 

[Hooty]

Re: Foam Below Floor

Howdy djohns19,<br />In a perfect world, the foam wouldn't absorb water w/out the skin. The trick is, it ain't a perfect world. All the horror stories you here about ureathane foam acting like a sponge are true ONLY if the mix ratios aren't followed precisely. If the instructions say 1:1, it has to be 1:1. That little bit that sticks to the inside of the "A" container, when you pour it into "B" is enough to screw up the ratio and the results is open-cell foam. Then, of course, there's the mixing. We used a helical mixer turning about 12 grand to mix in-place foam. I don't know what foam you're using but I would be real careful to seal it with fiberglass all around the edges and take all precautions to keep it in a water-tite enclosure. A friend of mine used empty plastic bottles to take up space in the area he was foaming, using less foam and accomplishing the same thing. It worked.<br />Anymore questions, lemme know.<br /><br />c/6<br /><br />hooty

 

[DJ]

Re: Foam Below Floor

Hooty,<br /><br />Thanks, you obviously know alot about this stuff. I will not be adding any, I just want to leave in what is in there. It doesn't seem to hold water. I poured some on it and it just sat there.<br /><br />You think it's OK?

 

[Hooty]

Re: Foam Below Floor

djohns19,<br />Another thing that will effect open cell/closed cell foam is the density. The higher the density, the less chance for open cells. Try to maintain 3-3 1/2 lbs./cu.ft.<br /><br />G'luck & c/6<br /><br />hooty

 

[Hooty]

Re: Foam Below Floor

If ya can, get a handfull of tha foam, weigh it (powder scales, etc.) and submerge it in water (weight on top) for a week or so, then re- weigh. That'll tell ya a lot.<br /><br />/6<br /><br />hooty

 

[DJ]

Re: Foam Below Floor

Thanks Hooty, will do.

 

[Philby]

Re: Foam Below Floor

It's not just the mixture as hooty says, its also the volume the foam has expanded into.<br /><br /> If the foam is expanded in a restricted volume it will, literally, be one big spoonge. If it has expanded to its natural volume, the crust will form and the cells are "hard "<br /><br />If you have a crust, you will be ok, even if the crust is broken or missing .

 

[DJ]

Re: Foam Below Floor

Thanks all, It had a crust, however it is broken in places.