I'm thinking of replacing some of my floatation foam blocks. Some of them turned into dust, some are simply gone. Someone suggested to me to use "great stuff"- you know, that really sticky foaming thing in cans that is sold at hardware stores... As far as I know, it's waterproof. I have seen it used for packaging. Another thing to think about is, in case I would want to get to the area where the foam is, I wouldn't really want the foam to stick to the fiberglass. So I'm thinking of lining a hull (or a compartment that I want to fill), with sheets of plastic(like painter's dropcloth made out of 1 mill polyethinene)...What do you think??? Has anyone used "great stuff" for floatation foam? It shouldn't degrade since it's not going to be exposed to the UV... So, Great stuff..yey or ney...? Any input is appreciated. THANKS! alexderiy@yahoo.com
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stuff about "Stuff"
I always think more flotation can't be a bad thing, and manufacturers should start using it in places like coach roofs where it can help in multiple ways (flotation, temperature control, structural rigidity), but there are some factors to consider: --abrasion: I read in a good book on cruising about an owner who tried this and found that constant hull flex caused the foam attached to the hull side to become soft and degrade over time. In their case it didn't turn to dust but rather to a gooey stuff, like old tape. Maybe this won't happen on a lightly used coastal cruiser, but dunno. --uv: it turns out that fiberglass and gelcoat are not really UV resistant: the parts of your boat that are not coated with paint or epoxy on the interior side are actually letting a lot of uv pass through to the interior (the "glass" in "fiberglass" is "see-through" to uv). Any foam you use on an unsealed hull will get a good dose of uv unless you preseal the area. --fire retardancy: remember that most of the foams are flammable. They sell non-flammable foams which cost more, but seem to me to be worth the price for this application. --drainage, wiring: keep an eye to how water is intended to reach the bilge when condensation forms on the hull, when incidental water comes on board, when windows leak; and don't be surprised at some of the places they may have routed wires or pipes...
I always think more flotation can't be a bad thing, and manufacturers should start using it in places like coach roofs where it can help in multiple ways (flotation, temperature control, structural rigidity), but there are some factors to consider: --abrasion: I read in a good book on cruising about an owner who tried this and found that constant hull flex caused the foam attached to the hull side to become soft and degrade over time. In their case it didn't turn to dust but rather to a gooey stuff, like old tape. Maybe this won't happen on a lightly used coastal cruiser, but dunno. --uv: it turns out that fiberglass and gelcoat are not really UV resistant: the parts of your boat that are not coated with paint or epoxy on the interior side are actually letting a lot of uv pass through to the interior (the "glass" in "fiberglass" is "see-through" to uv). Any foam you use on an unsealed hull will get a good dose of uv unless you preseal the area. --fire retardancy: remember that most of the foams are flammable. They sell non-flammable foams which cost more, but seem to me to be worth the price for this application. --drainage, wiring: keep an eye to how water is intended to reach the bilge when condensation forms on the hull, when incidental water comes on board, when windows leak; and don't be surprised at some of the places they may have routed wires or pipes...
Just remember that the standard stuff ...
gets pretty powerful when it expands... probably not good to fill holes all at once. Of course empty clear plastic bottles are good a filler as well? and free. I wonder what the combination could do. Just as long as the stuff doesn't soften them up while it cures. I was thinking about doing something like that on a 1969 Rhodes 19 to replace the foam that was turning into dust. Took 30 years for that originally installed foam to start to go. Vic "Seven"
gets pretty powerful when it expands... probably not good to fill holes all at once. Of course empty clear plastic bottles are good a filler as well? and free. I wonder what the combination could do. Just as long as the stuff doesn't soften them up while it cures. I was thinking about doing something like that on a 1969 Rhodes 19 to replace the foam that was turning into dust. Took 30 years for that originally installed foam to start to go. Vic "Seven"
Great stuff foam works very well as an
adhesive for extruded polystyrene foam that is sold as insulation. Usually pink or blue. Cut the rigid foam to fit the spaces and stick it in place with the great stuff. If you want it covered then you can use 3M spray adhesive and apply polyester fabric to cover the foam and protect it from damage. If the foam turns gummy then some solvent has attacked it. UV radiation will degrade it on the surface and cause it to powder but it won't cause it to go gummy.
adhesive for extruded polystyrene foam that is sold as insulation. Usually pink or blue. Cut the rigid foam to fit the spaces and stick it in place with the great stuff. If you want it covered then you can use 3M spray adhesive and apply polyester fabric to cover the foam and protect it from damage. If the foam turns gummy then some solvent has attacked it. UV radiation will degrade it on the surface and cause it to powder but it won't cause it to go gummy.
It is not water proof!
As it sets up the skin is water proof but if the skin is broken by any cutting or breaking of the foam body it will begin to absorb water. Your idea of lining the space is good but you might just use a variant of the bottle idea and fill plastic bags with the foam to fill the spaces between the rigid Styrofoam blocks. Ross has the best idea. As was pointed out, this stuff is powerful as it expands it can distort the shape of the compartment.
As it sets up the skin is water proof but if the skin is broken by any cutting or breaking of the foam body it will begin to absorb water. Your idea of lining the space is good but you might just use a variant of the bottle idea and fill plastic bags with the foam to fill the spaces between the rigid Styrofoam blocks. Ross has the best idea. As was pointed out, this stuff is powerful as it expands it can distort the shape of the compartment.
Great stuff is a closed cell foam
if you must shape the cured foam you can paint it. We are not concerned here with life jacket construction. I have used this material for many years and sunlight will discolor it but it will still be tough long after the wood that it was used with has rotted away. I made a pair of pontoons for an outrigger canoe with extruded styrene foam and "Great-stuff" almost twenty years ago and they are still in occessional summertime service.
if you must shape the cured foam you can paint it. We are not concerned here with life jacket construction. I have used this material for many years and sunlight will discolor it but it will still be tough long after the wood that it was used with has rotted away. I made a pair of pontoons for an outrigger canoe with extruded styrene foam and "Great-stuff" almost twenty years ago and they are still in occessional summertime service.
Great stuff, yey
this is a closed cell foam. it will not absorb water. as to expansion, the old formulations of urea foam did have potential to push things but the new formulations will not do this. 10 to 12 yrs ago when i rebuilt my rudder i used this closed cell foam to fill it and haven't had any more problems with water infiltration into since. s/v Que Pasa?
this is a closed cell foam. it will not absorb water. as to expansion, the old formulations of urea foam did have potential to push things but the new formulations will not do this. 10 to 12 yrs ago when i rebuilt my rudder i used this closed cell foam to fill it and haven't had any more problems with water infiltration into since. s/v Que Pasa?
great stuff is an open cell
It is not a closed cell. It is open. I called the company up and asked. I was told by their RD people to buy a two part foam, which I did, because theirs would eventually suck up water. Next: They spray foam (two part) onto homes and such in FLorida to insulate against the suns heat. If you are in that area, find one in the yellow pages and call them for either their services or info. They could probably spray your whole boat and not have any problems. I saw one company spray between the studs on a new house once and they were so good at it, estimating the expansion factor, that the cleanup crew only had several small areas to trim so the drywall would fit on the studs.
It is not a closed cell. It is open. I called the company up and asked. I was told by their RD people to buy a two part foam, which I did, because theirs would eventually suck up water. Next: They spray foam (two part) onto homes and such in FLorida to insulate against the suns heat. If you are in that area, find one in the yellow pages and call them for either their services or info. They could probably spray your whole boat and not have any problems. I saw one company spray between the studs on a new house once and they were so good at it, estimating the expansion factor, that the cleanup crew only had several small areas to trim so the drywall would fit on the studs.
i just checked the dow chemical site!
dow chemical specifically states on their web site, that great stuff is a closed cell foam. however it must be also stated that latex foam is an open cell foam and it will absorb water. which means that where latex is used, if it is used to insulate where water can get to it it will absorb water that can lead to rot. i tend to believe what is written by the manufacturer. as opposed to what someone stated. to much chance of misinterpretation. s/v Que Pasa
dow chemical specifically states on their web site, that great stuff is a closed cell foam. however it must be also stated that latex foam is an open cell foam and it will absorb water. which means that where latex is used, if it is used to insulate where water can get to it it will absorb water that can lead to rot. i tend to believe what is written by the manufacturer. as opposed to what someone stated. to much chance of misinterpretation. s/v Que Pasa
Hilti also makes a canned urethane
foam. It is strong, there is more in the can than great stuff. We started this thread about floatation foam and like life jackets 99 percent of the time it will stay dry and not be needed. The quantity of styrofoam that can be found washed up on beaches would seem to indicate that it does not become water logged very easily. Canned foam is more costly than extruded styrene foam so is well used as adhesive and gap filler. Those that choose to believe that great stuff will absorb water I suggest an experiment: Make a neat pile of foam and let it cure for a week. Next cut out a 2 inch cube and place it in a jar full of water and screw the lid on so that the foam is submerged. wait for a week and remove the lid and see if the foam still floats.
foam. It is strong, there is more in the can than great stuff. We started this thread about floatation foam and like life jackets 99 percent of the time it will stay dry and not be needed. The quantity of styrofoam that can be found washed up on beaches would seem to indicate that it does not become water logged very easily. Canned foam is more costly than extruded styrene foam so is well used as adhesive and gap filler. Those that choose to believe that great stuff will absorb water I suggest an experiment: Make a neat pile of foam and let it cure for a week. Next cut out a 2 inch cube and place it in a jar full of water and screw the lid on so that the foam is submerged. wait for a week and remove the lid and see if the foam still floats.
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