Need marine flotation foam, recommendations?

[acdc96]

Hello all,
I need to buy some 2-part Marine flotation foam for my 66 Lonestar. What do you recommend?
Is there a foam that's water resistant?

 

[wilkboater]

Mod EDIT: Iboats now carries boat rebuild products including flotation foam
http://www.iboats.com/Evercoat-Foam...15895223--session_id.927356602--view_id.38103​

******, each version they offer has some information about intended uses.

 

[TruckDrivingFool]

If it's a tin boat many opt for the rigid pink or blue insulation board instead of the two part. It's a cheaper option and should help avoid holding water against the AL hull and creating corrosion issues.

 

[Woodonglass]

Pink Slab foam being installed for flotation in an aluminum boat... Putting in on edge allows any water to freely flow back to the drain tube when the boat is properly stored bow up!!

 

[JonBrown]

Closed cell foam is what you are looking for. I never saw the slabs foam used but it looks like it could work? Make sure to research 2 part foam. It can expand at a rate that can push supports or stringers excessive.

 

[Kern Fischer]

I did some testing on a couple types of foam (not specifically marine). The two that I tested were the pink foam available in sheets at home stores, and Great Stuff in an aerosol can. Both do not absorb water. I weighed samples then submerged them in water for about two days. Neither gained any water weight.

I also tested the pink foam for a reaction to the epoxy resin I am using and there was no reaction. I have not tested the Great Stuff with the epoxy.

I also weighed an equal volume of each to see if there was any significant difference in density, which would affect the flotation lift from a given volume. They were essentially equal in that area also. I am using epoxy resin to bond the foam in place so that adds a little weight and decreases the pink flotation factor slightly.

My boat is fiberglass, not aluminum and I used the pink foam under my foredeck. The new structure I created for the foredeck makes it very strong and will keep the surface finish from cracking. I will probably also use it under the floor, bonded in place so there are no voids into which water can accumulate. If there are any small spaces that are hard to fill with the pink foam, I may shoot some Great Stuff in there. Since I will be filling the cavity completely, I do not plan to have any bilge drains. I expect the fully filled cavity to add considerably to the strength of the hull.

 

[acdc96]

I would use pink sheet foam, but the foam is structural cause it supports the floor. Is pink sheet foam structural?
Also, the original foam is in the boat but I removed about 2.5 ft in the stern cause I had to replace the transom and 2ft of the bottom due to corrosion. Surprisingly, the foam is not water logged, it sat uncovered in a Marsh for 30 years with the bare foam exposed to the weather.

 

[fhhuber]

Great Stuff breaks down with age... and is rapidly damaged by UV light.

 

[Frey0357]

ACDC: The method that I used in the photo shown above by "WoodonGlass" was to stand the foam on end and layer it between the ribs, but keeping it pressed between the new replacement flooring and the bottom of the boat. When many pieces of this pink foam are stacked in this manner with the flooring placed on top it has great structural capability, and as far as I am concerned it is stronger than the original spray in foam garbage that the factory used in my boat (Sea Nymph). I would highly recommend it! Also just to add, it is easy to work with, easy to cut with circular saw or razor blade!

Frey