Floatation Foam

[gm280]

I see so many questions concerning flotation foam in boats all the time. It is a huge question with a lot of interest. So I?ll present a few questions/ideas about this subject as well. Not having made a decision myself as to what type flotation foam I will use in my Tom Boy boat rebuild project (but getting close) I have a few questions about cut and place and mix and pour foams. The mix and pour looks appealing because it has the ability of expanding and therefore filling out hidden areas that could be hard to get to otherwise. But I have yet to hear one person say that the mix and pour foam is water proof. While it states it is water resistance, it doesn?t say water proof. And that brings me to wonder if I go through all this refurbishing effort and use mix and pour, am I going to again have wet foam in some years down the road...? I seriously don?t know for certain! The cut and place foam sheets you can buy at the Lowe?s and HD stores also sounds like a viable option. It would take a little more time and some interesting cuts to fill in the voids, but it IS totally water proof and not just water resistant. So excluding cost for either option, it looks like the cut and place would be the winner. BUT...what if you used mix and pour foam and poured it into plastic sheeted areas and when it dried (for lack of the correct term) you could simple remove the poured foam and then seal that foam somehow to increase its? ability to NOT absorb water. But what could you use on those foam chucks that would completely seal it and not eat the foam?

Okay those are just some ideas I still have floating around in my tiny little brain cells yet...

:deadhorse:

 

[ezmobee]

Re: Floatation Foam

I like a sheet foam/pourable foam hybrid solution. Use as much sheet as you can and fill in the gaps with pourable.

 

[jackd1023]

Re: Floatation Foam

My idea is to put 1/2" pvc under pur in(drain), can you use large plastic bags and pour the foam into that? Just an idea that the foam will still expand but will not get into drainage, would still be floatation right??

 

[Teamster]

Re: Floatation Foam

It is my understanding that all foam will soak up water over time,....

The only real variable is the kind of care an owner put's into maintaining the boat,.........

A well taken care of boat with pour in foam should last for decades,.........

If you leave it full of water it might last a few years,..........

 

[colbyt]

Re: Floatation Foam

Speaking with absolutely no first hand knowledge on the subject, I have not read of any that is 100% waterproof. 95-98% closed cell is the best I have read of. If I were pouring into a boat cavity I would create water channels in the low points; most likely with PVC pipe sections.

Based on my own computations, the pour foam is about 2 times the money and I estimate 2-3 times faster.

remove the poured foam and then seal that foam somehow to increase its? ability to NOT absorb water. But what could you use on those foam chucks that would completely seal it and not eat the foam?

The us composites site says that their foam is suitable for glassing over. I assume that means epoxy safe. I also believe that is over kill for boat flotation.

 

[kfa4303]

Re: Floatation Foam

Hi gm. Flotation foam is always a good idea. The key is to get closed-cell foam that will not soak up any water over time. Most folks here in the forums like to use the pink/blue insulation board available at the big box stores. It's relatively cheap, easy to work with and entirely removable when/if the time should come. Pourable foam, on the other hand, can/will get into every nook and cranny and will be a real PITA to get out. It can also do damage to the boat if too much is poured into a confined space and may be a little tricky to track down. The general rule of thumb is that 1 cu. ft. of air/closed cell foam will float approx 60lbs of boat. Wile the foam board is most popular, some folks have also used large, sealed, plastic bottles and pool noodles below decks as well. Really anything that traps air without becoming waterlogged will work.

 

[Badfish95]

Re: Floatation Foam

I'll bite...

I agree the key for any foamed hull is proper care by the owner. When you buy a boat, you are essentially buying the previous owner. If his garage/covered slip is immaculate, you are probably good to go. If the boat is in the yard next to an 84' mustang on blocks with no cover on it, run away...fast.

After much research, I eventually went with the pour in foam. The structural laminating benefits meant more to me than the water intrusion issues. If the deck is sealed properly and the boat is kept out of monsoons, the hull should last a very long time. That being said, you will still spend weeks debating this topic. Good luck with your choice of foam.

 

[gm280]

Re: Floatation Foam

First of all thanks to everybody that responded with suggestions. The large trash bag idea sound pretty good. The mix and pour is still on the table but even if you install PVC pipe with or without holes in them to allow for drainage, the poured foam will invade those holes as well. I already ruled that idea out. It sounds like a good idea, but since the mix and pour does such a great job of filling in all the little crevices, it would equally plug up any drilled drainage holes in the PVC too... And I don't really like the pool noodles either. So that option is also out. So I do like the cut and place sheet foam yet as well. I need to decide soon because that issue is coming up soon... Thanks again guys... :gossip:

 

[glenn property of pam]

Re: Floatation Foam

i see the pour foam even the 2lb adds strenth to the hull. On a fiber glass boat i would pour in but on a tinny i would consider sheet foam as that allows for a fast weld patch if it should ever need one. Theres no fast fix on a fiber glass boat so i would take the extra strenth and ridgidity

 

[tpenfield]

Re: Floatation Foam

Sorry to be late to the 'foam party' . . . but I thought that I would add my thoughts to the discussion.

The 2-part polyurethane foam used in boats has gotten a bad name in some cases due to is becoming saturated in a rotting boat. Is it a culprit or a victim ?

Here is the information about polyurethane foam that is on the the US Composites web site

Frequently Asked Questions - General

So water absorption in polyurethane foam is a process that takes years. It seems like extruded polystyrene sheets (i.e. the pink or blue insulation sheets a la HD or Lowes) have very good water resistance, perhaps more so than polyurethane.

I think the key difference is the structural strength that is gained from the pour-in polyurethane foam versus the mere flotation qualities of expanded polystyrene.

As mentioned, maintenance is the key . . . if water gets into the cambers of foam and has nowhere to go, it will eventually penetrate the foam over many years. I'm not so sure that polystyrene would fair much better than polyurethane in this sort of circumstance.

I would hate to see someone omit foam from their boat restoration where it was really needed, either for flotation or for strength . . . or both . . . for the fear of water absorption, when it is really a matter of maintenance.

 

[magnumdeke]

Re: Floatation Foam

Personal decision here, for me pourable foam is the only really approved and evaluated product, yep some boats use the white bead board back in the day, pourable is the standard. i can do the math with pourable and be reasonably certain as to what I have in floatation, therfore that is what I will be using.