flotation foam
- Thread starter larizon
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spray foam
You can get aerosal cans of expandable foam at any big box (read: Home Depot, Lowes, etc.). I've used it to fill post holes and it's extremely durable and does an excellent job. However, once it's in, it is IN! In other words, if you need to replace a deck fitting, for example, and need to fasten it underneath, you're gonna have to DIG.
Better to find blocks of dense flotation foam and place them in the areas you want to fill.
Hope this reply makes sense.
Dave
You can get aerosal cans of expandable foam at any big box (read: Home Depot, Lowes, etc.). I've used it to fill post holes and it's extremely durable and does an excellent job. However, once it's in, it is IN! In other words, if you need to replace a deck fitting, for example, and need to fasten it underneath, you're gonna have to DIG.
Better to find blocks of dense flotation foam and place them in the areas you want to fill.
Hope this reply makes sense.
Dave
spray foam
I've looked into replacing some of the foam in my mac 25 as well. Good sources on youtube.com for expanding foam and its application. (TAP plastics is a source up here in Nor.Cal) It seems like there is a lot of unusable space that could be "traded" for areas that could be used for storage like the v berth. You'll want to compare the floatation caracteristics of the new 2 part foam to the styrofoam blocks. This type of expanding foam allows you to pour into sections with a barrier (like plasctic bag) to allow for removal for any hull repair or access in the future. Also, want consider the amount that you remove with the amount you are reinstalling...
I've looked into replacing some of the foam in my mac 25 as well. Good sources on youtube.com for expanding foam and its application. (TAP plastics is a source up here in Nor.Cal) It seems like there is a lot of unusable space that could be "traded" for areas that could be used for storage like the v berth. You'll want to compare the floatation caracteristics of the new 2 part foam to the styrofoam blocks. This type of expanding foam allows you to pour into sections with a barrier (like plasctic bag) to allow for removal for any hull repair or access in the future. Also, want consider the amount that you remove with the amount you are reinstalling...
Seabass mentioned something important. Plastic bags. If you ever wanted to remove the foam it will only be stuck to the inside of the bags. They will be contured to the space you install them and might be stuck that way. Use contractor garbage bags. They are 6 mill thick.
Watch for expansion! I have seen the foam expand enough to move window sashes making the window very hard to open! It might push your hull out of its proper shape.
I have a buddy that spray foams houses and we were talking about doing the inaccessible areas of my 26D. He called me the next day and warned me that there is a foam that actually absorbs water! Might want to avoid that one.
Good luck and please post pictures.
Watch for expansion! I have seen the foam expand enough to move window sashes making the window very hard to open! It might push your hull out of its proper shape.
I have a buddy that spray foams houses and we were talking about doing the inaccessible areas of my 26D. He called me the next day and warned me that there is a foam that actually absorbs water! Might want to avoid that one.
Good luck and please post pictures.
My understanding is the aerosol cans of foam at HD and Lowes are open cell, and not useable for flotation. Flotation needs to be closed cell. Perhaps you could bag it...if so...one guy suggested using only the window and sash stuff as it does not expand much, and then spray in SLOWLY so you give it room to expand.
Jeff
Jeff
I've done the bag thing.... It works fine...The spray foam is expensive so what I did was fill a large 30 gal. lawn bag (lawn bags are heavier gauge plastic) with packing peanuts and other small scraps of Styrofoam, fit it into the space I wanted to fill and then fill it it with spray foam.
... and I could be wrong but I'm almost certain the spray foam is closed cell. The stuff is designed to fill cracks in walls, seal up through holes in walls etc. so it is intended to be exposed to the elements. I have spray foam that I used in and around my sheds that is 10 years old and I see not evidence that it has absorbed any water. ... ????
... and I could be wrong but I'm almost certain the spray foam is closed cell. The stuff is designed to fill cracks in walls, seal up through holes in walls etc. so it is intended to be exposed to the elements. I have spray foam that I used in and around my sheds that is 10 years old and I see not evidence that it has absorbed any water. ... ????
Larizon,
The cleats, on may Mac 25, only had a piece of 1/4" plywood under them. They became loose and I had to get back into the hull by removing the blocks on the starboard side and cut out the bulkhead on the port side in order to get back in to the port rear cleat by removing the foam blocks. I epoxyed plywood strips to the inside of the area I cut and then screwed the piece, I cut out, to the strips. While I was at it, I replaced the cleats with nice chrome one's backed up with a 1/4" aluminium plates underneath. To each their own put I wouldn't use canned spray foam if you ever need to get back in there for any reason.
The cleats, on may Mac 25, only had a piece of 1/4" plywood under them. They became loose and I had to get back into the hull by removing the blocks on the starboard side and cut out the bulkhead on the port side in order to get back in to the port rear cleat by removing the foam blocks. I epoxyed plywood strips to the inside of the area I cut and then screwed the piece, I cut out, to the strips. While I was at it, I replaced the cleats with nice chrome one's backed up with a 1/4" aluminium plates underneath. To each their own put I wouldn't use canned spray foam if you ever need to get back in there for any reason.
Spray foam IS open cell. and it will float, for a little while. left immersed in water it becomes waterlogged an heavy. if you can shoot it off in a bag, you have a pretty good chance of it working out fine. assuming the bag doesn't get water in it for long periods. -I've used it on my boat to hold closed cell foam and stryofoam, just don't use 'great stuff' on the floor. or areas where it can get waterlogged.
-fwiw, before the mac, I owned a 88 dolphin (20'open fish) that used no wood and some spray foam for flotation... when I got it it has been waterlogged for years, and sat about 2" lower in the water that original. needless to say, it would take on water over the back, in a choppy anchorage.
http://www.homedepot.com/Building-M...1&keyword=foam insulation sheet&storeId=10051
closed cell foam is the way to go (blue and red sheets at home depot, for insulation)
-fwiw, before the mac, I owned a 88 dolphin (20'open fish) that used no wood and some spray foam for flotation... when I got it it has been waterlogged for years, and sat about 2" lower in the water that original. needless to say, it would take on water over the back, in a choppy anchorage.
http://www.homedepot.com/Building-M...1&keyword=foam insulation sheet&storeId=10051
closed cell foam is the way to go (blue and red sheets at home depot, for insulation)
Spray foam is good but costly. Large volumes I use plastic bottles - milk, pop, etc and they are mostly free! ................unless you have return deposit
I concur with Mr. Bill. I had a Rinker V205. The area under the floor was filled with pour in foam (similiar to the spray on stuff I think). The foam was so water logged, I'm not sure what the net benefit was. To be fair, the boat sat for a long period of time with water covering the foam. I removed the foam and bad wood...and restored(pore in foam big $)...what a project that was.....never again. I like the milk jug idea.......they work well to mark channels ;-)
Hey Guys...
It is important not to put all expanding foams in the same category. The latex spray foam is open celled... you don't want that on a boat... but the polyurethane spray foam (Grate Stuff) is closed celled and is fine to use on a boat. Two part polyurethane is also good to use on a boat. Additionally polystyrene foam (styrofoam) is closed cell and can be "glued" together using Great Stuff. So you can put small pieces of styrofoam in a plastic bag, shove it into some small space and "glue" it together with Great Stuff squirted into the bag.
I can post pics if anyone wants....
It is important not to put all expanding foams in the same category. The latex spray foam is open celled... you don't want that on a boat... but the polyurethane spray foam (Grate Stuff) is closed celled and is fine to use on a boat. Two part polyurethane is also good to use on a boat. Additionally polystyrene foam (styrofoam) is closed cell and can be "glued" together using Great Stuff. So you can put small pieces of styrofoam in a plastic bag, shove it into some small space and "glue" it together with Great Stuff squirted into the bag.
I can post pics if anyone wants....
I beg to differ.
great stuff forms a skin, and that skin resists water intrusion. (pretty well), but it you puncture the skin, cut it after cured, its open and will absorb water... if you shoots off some it forms a ball like glob, but cut it in half and stick in water for 24hours and see...
fwiw, a buddy's 25' welcraft almost sank, and after that it had a list to stb 20degrees. we tried to get the water out, but never could... we figured there was foam below deck holding the fuel tanks. - and he sold it... on a trailer. buyer beware!
I've used it for lots of things, including cars and boats.....and love it, but its does have limits. -oh, and wear gloves! it just doesn't come off your hands! kinda like super glue...
great stuff forms a skin, and that skin resists water intrusion. (pretty well), but it you puncture the skin, cut it after cured, its open and will absorb water... if you shoots off some it forms a ball like glob, but cut it in half and stick in water for 24hours and see...
fwiw, a buddy's 25' welcraft almost sank, and after that it had a list to stb 20degrees. we tried to get the water out, but never could... we figured there was foam below deck holding the fuel tanks. - and he sold it... on a trailer. buyer beware!
I've used it for lots of things, including cars and boats.....and love it, but its does have limits. -oh, and wear gloves! it just doesn't come off your hands! kinda like super glue...
What do you guys think about using the great stuff in the top of the mast as a precaution for turning turtle?
it should never get to that, if the keel is down, but..
I'd use pool noodles, they are closed cell. plus if you have wires in there, it helps a lot to keep it quiet at night.
+ the great stuff is heavy if you make it dense. (which can be a good thing in the right application, like keeping something from compressing)
I'd use pool noodles, they are closed cell. plus if you have wires in there, it helps a lot to keep it quiet at night.
+ the great stuff is heavy if you make it dense. (which can be a good thing in the right application, like keeping something from compressing)
MrBill
I went to the Dow site and did a bit of reading...
http://building.dow.com/na/en/products/sealants/windowdoor.htm
It would seem that their info is a bit "confusing" ... they claim it is closed cell foam but also mention the "skin" that you also mentioned. I guess it is worth doing the experiment myself. I'm going to put a piece in a jar, fill it to the top and close it up. That way the foam will actually be submerged... I'll let you all know what I find.
I don't think your friend's boat is a conclusive test case since you don't know what kind of foam was in his boat.
r
I went to the Dow site and did a bit of reading...
http://building.dow.com/na/en/products/sealants/windowdoor.htm
It would seem that their info is a bit "confusing" ... they claim it is closed cell foam but also mention the "skin" that you also mentioned. I guess it is worth doing the experiment myself. I'm going to put a piece in a jar, fill it to the top and close it up. That way the foam will actually be submerged... I'll let you all know what I find.
I don't think your friend's boat is a conclusive test case since you don't know what kind of foam was in his boat.
r
( I did too, its says outdoors, but nothing I could find on open or closed cell)
I agree on the wellcraft, not sure why it listed, but we turned lock to lock on a plane to get all the water out, 360's hole shots, etc, no luck.
on the dolphin, I cut into the stern deck to run new teleflex and bilge wires. it was oily greasy wet and heavy. -fwiw, I added aluminum 'skirts' around the engine to raise up the transom a bit, so the gap was much less than the 2' it had... which did help some.
I've used the great suff a lot. (and before that the 2 part you pour and mix -that was some scary stuff, since it expanded so much and got very hot!)
try 2 jars and cut one blob in half. the other full. they will both float, the one that was cut will float less and weigh more.
-fwiw I use the closed cell foam they often ship computer in. (or the stuff they sell in sheets at HD).
-I'm using it on the mac, mostly as glue.
http://i5.photobucket.com/albums/y159/ftldiver/mac/6de06ea4.jpg
not the best shot, but its the glue for the closed cell packing I stuck to the hull. it doesn't get much water there so its fine.
like I said, anyplace its not cut or not immersed in water it should be OK.
http://i5.photobucket.com/albums/y159/ftldiver/mac/7132c902.jpg
but its not closed cell.
its also hard to use 1 can 2x.. the nozzle clogs fast.
-ymmv.
I agree on the wellcraft, not sure why it listed, but we turned lock to lock on a plane to get all the water out, 360's hole shots, etc, no luck.
on the dolphin, I cut into the stern deck to run new teleflex and bilge wires. it was oily greasy wet and heavy. -fwiw, I added aluminum 'skirts' around the engine to raise up the transom a bit, so the gap was much less than the 2' it had... which did help some.
I've used the great suff a lot. (and before that the 2 part you pour and mix -that was some scary stuff, since it expanded so much and got very hot!)
try 2 jars and cut one blob in half. the other full. they will both float, the one that was cut will float less and weigh more.
-fwiw I use the closed cell foam they often ship computer in. (or the stuff they sell in sheets at HD).
-I'm using it on the mac, mostly as glue.
http://i5.photobucket.com/albums/y159/ftldiver/mac/6de06ea4.jpg
not the best shot, but its the glue for the closed cell packing I stuck to the hull. it doesn't get much water there so its fine.
like I said, anyplace its not cut or not immersed in water it should be OK.
http://i5.photobucket.com/albums/y159/ftldiver/mac/7132c902.jpg
but its not closed cell.
its also hard to use 1 can 2x.. the nozzle clogs fast.
-ymmv.
"I've used the great suff a lot. (and before that the 2 part you pour and mix -that was some scary stuff, since it expanded so much and got very hot!)?"
.......that's the stuff I used to replace what I thought was original. It had a"skin" but was water logged. When I poured it in the holes on top of the plywood, I thought it was going to pop the plywood off the stringers! .....and the spray stuff has got to be one of the stickiest,messiest substances I can think of! And it gets everywhere when you turn your head for a second....kinda like 5200. Interesting though. The blob of waterlogged poured in foam I removed.....eventually dried out sitting in the garage for a few months.
.......that's the stuff I used to replace what I thought was original. It had a"skin" but was water logged. When I poured it in the holes on top of the plywood, I thought it was going to pop the plywood off the stringers! .....and the spray stuff has got to be one of the stickiest,messiest substances I can think of! And it gets everywhere when you turn your head for a second....kinda like 5200. Interesting though. The blob of waterlogged poured in foam I removed.....eventually dried out sitting in the garage for a few months.
fwiw, what I've done is make a kind of form with masking tape, shoot it off, then wait maybe 10-15 min, where its skinned, then put some more tape to the outsides, and push it in. which makes it more dense. does noting to improve the waterproof-ness, but its now pretty hard, and dense. and after a day you can peel off most of the tape. in this manner, I've used it on cars to hold things together. (body work and radiator openings.)
its OK, and has its uses, but there are better alternatives IMHO for flotation.
Harbor freight has blocks of stryrofoam they will give you. (they use it to ship their trailers).
its OK, and has its uses, but there are better alternatives IMHO for flotation.
Harbor freight has blocks of stryrofoam they will give you. (they use it to ship their trailers).
I don't like milk jugs because most of them are now pop off tops and not screw on. I use one gallon jugs that soap came in, they have twist off tops and are made of heavier plastic
than milk jugs. They are also good for extra water for flushing toilet, etc. I get them from my local health food store for free, got dozens of them. I also use pool noodles in all the small spaces. They can be bent into all kinds of shapes to fit into odd spaces and can be played with when needed. They are about 5 feet long and 2 to 4 inches in diameter and can be gotten at any large department store and go on sale every fall.
than milk jugs. They are also good for extra water for flushing toilet, etc. I get them from my local health food store for free, got dozens of them. I also use pool noodles in all the small spaces. They can be bent into all kinds of shapes to fit into odd spaces and can be played with when needed. They are about 5 feet long and 2 to 4 inches in diameter and can be gotten at any large department store and go on sale every fall.
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