Flotation foam

[plagueonthewater]

I am in the process of restoring my 88 bayliner Capri. I was talking to a friend about using two part foam after I put the deck down. He stopped me right there and told me not to. He said that there were too many factors that affect the way that the foam expands. He also told me that if I pour too much and the deck was already sealed that the foam could still lift the deck or make it buckle as it expands. Was he being extreme or is two part foam really a bad option. If it is a bad option what are the alternatives?

 

[92excel]

Re: Flotation foam

Read this:
http://forums.iboats.com/showthread.php?t=283667

 

[erikgreen]

Re: Flotation foam

Short answer: If you calculate correctly it won't buckle the deck. It can if you're dumb, but many other bad things will happen to you if you are

It's a good idea to pour the foam before you put the deck down to make sure that overexpansion isn't a problem. It's easy to shave the top of the foam level with the bottom of the deck.

Erik

 

[Mark42]

Re: Flotation foam

Most members who poured foam did it after glassing the deck down. Then cut holes in the deck for pouring and expansion. After the foam oozes out the holes, cut it out, replace the hole plug and glass over again. Some members put weights on the deck too. Like concrete block, etc.

The advantage to pouring the foam after the deck is on is that it glues the entire boat together into one very rigid structure. Plus the foam will expand into crevices better if the deck is on.

 

[Lou C]

Re: Flotation foam

I poured the foam before putting the deck down, then cut it flush and glued (and used stainless screws) the deck down to the stringers/foam. No worries about breaking things loose and everything gets filled (and you can see it for sure). Worked out fine boat is way more solid than it ever was before.

 

[chicknwing]

Re: Flotation foam

I poured the foam before putting the deck down, then cut it flush and glued (and used stainless screws) the deck down to the stringers/foam. No worries about breaking things loose and everything gets filled (and you can see it for sure). Worked out fine boat is way more solid than it ever was before.

I did the same as stated above with the same result. But the other post above is correct as well. Which make you feel more at ease is the correct choice. I personally would do it before putting the deck down.

TC

 

[salty87]

Re: Flotation foam

the factory foam pour on mine left nice pockets on top of the foam to collect puddles of water. that was sweet of them.

kind of a double-edged sword...you need enough to not leave voids but not too much. and, unless you cut holes all over the place...i don't see how it can possibly get everywhere.

i put my foam in before the deck too. don't forget the drainage though.

 

[erikgreen]

Re: Flotation foam

If you really want your deck glued down to the foam (which is the only real reason I can see to want to have it in place first) then why not pour the foam, level it, make sure there are no air pockets, and apply epoxy with a filler or another thin layer of foam to the top before you add the deck?

You can pour as many layers as you want, they'll all stick to each other. Injecting the foam through a small hole makes sense if you're going to be leaving the deck in place, but it just makes things harder if you're going to be putting the deck on later anyway.

Erik

 

[Tail_Gunner]

Re: Flotation foam

the factory foam pour on mine left nice pockets on top of the foam to collect puddles of water. that was sweet of them.

kind of a double-edged sword...you need enough to not leave voids but not too much. and, unless you cut holes all over the place...i don't see how it can possibly get everywhere.

i put my foam in before the deck too. don't forget the drainage though.

It is really very simple, cut your deck to porportion..(that is the hard part) map out all of your pocket's or voids.... place 2" vent holes every 10 inches. Lay down the deck and semi secure it. You should now know just how much volume each pocket of void contains...aka cu in or feet. Mix youself about 15% more volume than you need..or 10 or 5 and pour away. Two part foam really expands @ the RIGHT temp, within minutes it will be pushing out the excess foam out of the vents. Pry off the excess take a angle grinder cut off the rest and you will have one solid deck and glued down... Its not moving trust me. One void at a time

http://forums.iboats.com/showthread.php?t=169006

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[salty87]

Re: Flotation foam

i'm having flashbacks to digging wet foam out of every nook and cranny. if you want it to drain at all, please don't fill every square inch with foam.

2" vent holes every 10" and you've made swiss cheese out of the fancy ply.

that just sounds like a lot of work to me. i figured that i wasn't going to defeat water so i left ways for it to get out once it invariably finds a way in.

line the area with plastic, pour your foam into the plastic, peel the plastic off your new custom fitted foam blocks, drop them into the hull and you've got drainable foam. you can trim the top when you lay the plywood down.

you might lose a small percentage by volume but i'll take that in exchange for it never getting saturated again.

add a few limber holes to the stringers to let any water that might get in there drain to the bilge.

 

[jcsercsa]

Re: Flotation foam

HI all ,

Well I poured the foam before the deck . I was afraid , when i was doing it someone told me on here that they poured the foam and there was 3 guys , all good size, and they did something wrong and got to much in and it lifted all three guys jumping up and down on it trying to get it to go down , well no luck they had to redo the deck !!

I dont agree with how they got it in the sticky !!

I say , pour it frist then take a hand saw and cut it flush !! you will get it fuller and you wont miss any spots , it cuts really easy !! John