I see a lot of guys using spray in foam for their boats.

Designs for inboard or outboard power

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I see a lot of guys using spray in foam for their boats.

Post by Jimmy70 »

As I have been cruising the forums here and there I ran across the one forum in Canada with the minimax boats and most of them are using spray in foam for bouancy in case it swamps. I was wondering if they are using this foam stuff you buy in a hardware store to seal up cracks and joints. The can says it is water proof, paintable and can be formed. So I guess what I am trying to say is "Has anyone one of you used this type of foam for that purpose."
If you have let me know as I have some cavities that I would like to add this to before I skin the boat.
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Post by KnottyBuoyz »

I've seen it used also. Not large scale mind you but small areas to be covered and for fastening sheet foam or empty pop bottles for buoyancy. Without knowing the composition of the foam I'd be inclined to put a coat of latex paint over it after it's cured in case it outgasses something nasty.

We're going to spray foam the entire inside of our boat and will have that done by pros. It's being done more for insulation than flotation though.
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Post by Caber-Feidh »

In general epoxy is safe over most expanding foams... at least from the foam's point of view, if not your boat's.

For the most part the DIY store spray in foams are NOT closed cell. they will absorb, and hold water. There are 2-part, and thermal-applied foams that are a bit more water resistant.

Any one that has done much restoration can tell you the horror stories of waterlogged flotation boxes, and rotted wood from poorly thought-out foam jobs.

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Post by leakcheck »

Hey Dog Lover !!

What is that in your profile picture that is screaming along leaving a mile long rooster tail ???


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Post by Dave Grason »

Steve, Steve, Steve. That rooster tail is NOT a mile long. It's only 9/10ths of a mile. If I've told you once I've told you a million times. Don't exaggerate.
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Post by china »

i was reading a book last week and it was suggested that intead of spray on foam that it was better to use foam/polysterene blocks instead.

spayfoam is messy and if you need to make a repair to the hull it is hard/messy work to scrape it all away.

plus when it gets wet it will mould and smell terrible. and its expensive.

thats all i can remember but will check the book this weekend for more info. it didnt sound very good though.

better the blocks so you can remove them when it's time to gain access to remote areas, plus it'll be cheaper.

if you do use the spray on foam, then dont forget to wear a mask as it contains intoxicating chemicals.

i would stick to foam blocks cut to shape and sealed in.
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Post by Caber-Feidh »

That is my old vintage Eliminator "violator" (was a scorpion built for jet drive). Chev crate ZZ572 on an aggressor pump. We put 2-4 degree wedges under the diverter. Not too fast with that much trim, but made for a cool pix.

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Post by BruceDow »

If using DIY expanding foam, I would be careful about fuel and oil resistance, and flammability. I don't know that they are NOT OK... I just don't know that they ARE OK.

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