closed cell foam floatation

[Fred Padgett]

I am working on an older Sylvan Aluminum boat. I tore the floor out and it had crappy old white floation material that was waterlogged and disentigrating. When I go to replace it, I see that there are some options, The Pink rigid board insulation, is one, the other is the two part expanding foam that you pour in place.
My question is, in place of the exanding pour in foam that marine suppliers offer, can you use the expanding foam that is sold in Home supply stores that is used in the ground to anchor things like fence posts and mail boxes. This is a two part system, and I think must be closed cell, as it is there not only to anchor the post but to keep moisture away from the posts to prevent rot all year long.

Any answers are appreciated.

 

[airshot]

Hmmmmm...never heard of that stuff....even us old dogs can still learn new things I guess.....

 

[Still Afloat]

I found a post hole foam product by Sika. I can‘t say if it would be a problem for aluminum since their product and material data sheets aren’t complete.

I did gleam that each packet produces 0.7 cubic ft. You need to compare to marine products to see if it is cost effective.

The product doesn’t win my vote from a safety point of view. The mixing time in the bag is only15 seconds before a high risk of the bag bursting and spraying the stuff all over you. The respiratory health risk is high, OSHA category 4. Make sure that you have the right type of respirator and work with the stuff outdoors. Also goggles, chemical resistant gloves, etc.

 

[LDUBS]

I am working on an older Sylvan Aluminum boat. I tore the floor out and it had crappy old white floation material that was waterlogged and disentigrating. When I go to replace it, I see that there are some options, The Pink rigid board insulation, is one, the other is the two part expanding foam that you pour in place.
My question is, in place of the exanding pour in foam that marine suppliers offer, can you use the expanding foam that is sold in Home supply stores that is used in the ground to anchor things like fence posts and mail boxes. This is a two part system, and I think must be closed cell, as it is there not only to anchor the post but to keep moisture away from the posts to prevent rot all year long.

Any answers are appreciated.

Since you say any answers, I'll give it a shot, Lol. If the situation allows, like an enclosed space, I would opt for rigid styrofoam blocks as opposed to two part expanding foam. Reason being it will make life a lot easier if I had to remove any some time down the road.

If two part foam is used, I recall a thread by @onthewater102 where he put a plastic barrier between the foam and hull. He also put in drainage channels. I thought it was a pretty good example of a best practice.

 

[LDUBS]

Ooops - deleted.

 

[Fishingman48]

With help from these fella's, I did my troller over thing is I didn't know that the blue board is better than the pink / so if that helps if you're going with board. I ALSO USED THE 2 PART "marine " / Certain area's board just didn't work & had to fill in some gaps . Oh! you may want to check on the chemical composition! As that construction foam for outside use on post />>>>>

Postloc is a closed-cell urethane product. It does not float or degrade in water but stays solid and holds firm even in marshy and wet areas like culverts. It even keeps groundwater clean, as the foam bonds directly to the pole and prevents wood treatment used on most poles from seeping into the ground.​

2-PART> Closed Cell, for marine use I got through e-bay or

https://www.generalplastics.com/products/r-3300 > check this foam out/ Just my two cents/ sense ???

 

[Stand Up]

I have used post foam many times. It will never explode in the bag unless total neglect is shown during the mixing process, but even then, highly doubtful. However, I think it would be advisable to mix a batch up and experiment with it first. Put a piece of foam in a tub or a barrel of water and see what happens. Does it take on water? How heavy is it? What degree of adhesion does it have? Will it react to the aluminum and cause the erosion of the aluminum? How much buoyancy does it have, or how much foam will be required in your boat to keep it afloat?
I can tell you it will last a long time in the ground and it holds posts well. It does not allow water to pool around a post causing rot.
It's good stuff for what it is intended for.

 

[Still Afloat]

Interesting. I got the high risk of bursting straight from the Sika website. Maybe their lawyers are just overactive.

 

[LDUBS]

Corporate risk management for product liability exposures.

 

[Still Afloat]

When I read it I thinking that it would be insane to sell product to the public that could burst in your face. Having said that, stuff happens given the right conditions.

 

[Al U Minium]

Here is a link

https://www.tinboats.net/threads/1968-mirrocraft-rebuild-continues.41185/
It shows what I did with the 2 part foam used for posts and mailboxes

It is holding up very well and not deteriorating

 

[thill]

I like to use both. Cut, stack and place the sheet foam in the area you want. Then use a shot of fill foam around the edges, corners or other places as needed. This secures the sheet foam in place solidly and completes the installation.

Just don't use too much, so it doesn't expand and interfere with other things.

 

[Billyfish]

If you dont need it for structure, consider EPS cut to fit. My experience is all pour foam holds water, so if water is getting in, the foam get wet. EPS does not take on water, its used for floating docks that are in the water for decades. Here is a fiberglass one I did some years ago.

 

[LDUBS]

If you dont need it for structure, consider EPS cut to fit. My experience is all pour foam holds water, so if water is getting in, the foam get wet. EPS does not take on water, its used for floating docks that are in the water for decades. Here is a fiberglass on it did some years ago.

Good ol styrofoam!

 

[InSaneFisherMan]

I would refer to the USCG boat builders guide for flotation. 2hp outboard and above are required to meet floation, stability, and level floation requirements.

Changing foam types/amounts/ect, may not give you the correct flotation results you are trying to acheive.

 

[Bailey Boat]

BLUE foam board is closed cell, the PINK isn't. Choose accordingly...

 

[Buster]

BLUE foam board is closed cell, the PINK isn't. Choose accordingly...

Blue (DuPont or Dow) and pink (Owens Corning) are both XPS foam and are both closed cell. Same chemicals, same process. Blue has a thin plastic film on both sides and pink doesn't, but the foam is the same for all practical purposes.

 

[EdP]

I am working on an older Sylvan Aluminum boat. I tore the floor out and it had crappy old white floation material that was waterlogged and disentigrating. When I go to replace it, I see that there are some options, The Pink rigid board insulation, is one, the other is the two part expanding foam that you pour in place.
My question is, in place of the exanding pour in foam that marine suppliers offer, can you use the expanding foam that is sold in Home supply stores that is used in the ground to anchor things like fence posts and mail boxes. This is a two part system, and I think must be closed cell, as it is there not only to anchor the post but to keep moisture away from the posts to prevent rot all year long.

Any answers are appreciated.

I

 

[Challenger]

With help from these fella's, I did my troller over thing is I didn't know that the blue board is better than the pink / so if that helps if you're going with board. I ALSO USED THE 2 PART "marine " / Certain area's board just didn't work & had to fill in some gaps . Oh! you may want to check on the chemical composition! As that construction foam for outside use on post />>>>>

Postloc is a closed-cell urethane product. It does not float or degrade in water but stays solid and holds firm even in marshy and wet areas like culverts. It even keeps groundwater clean, as the foam bonds directly to the pole and prevents wood treatment used on most poles from seeping into the ground.​

2-PART> Closed Cell, for marine use I got through e-bay or

https://www.generalplastics.com/products/r-3300 > check this foam out/ Just my two cents/ sense ???

I notice in your description that this pruduct does not float in water. Doesn't that defeat the purpose of the foam?

 

[LDUBS]

I notice in your description that this pruduct does not float in water. Doesn't that defeat the purpose of the foam?

That postdoc product is intended for use when setting a post in the ground. From that perspective, it makes sense you wouldn't want it to float -- might float your clothesline post right out of the ground! I sure wouldn't use it in my boat.