Foam Technique

[imported_John_Galt]

I have question on foam.

Do I foam before I deck or do I cut plugs and pour 2 part foam after deck is installed and anchored?

I seems to me that pouring after deck install would force the foam to all of the tiny crevices that will remain void if I foam before installing the deck. But I worry that too much foam will cause the deck to be placed under too much stress if I over fill it.

Has anyone done this and can tell me the pit falls before I screw up my redecking project?

Thanks

John

 

[ondarvr]

Re: Foam Technique

I put the foam in before putting the floor on, then cut off the over filled areas. While most of the area will fill with foam when it's poured in through the holes, there will be large voids, plus if you add too much it can push the floor up and damage it. It can be done either way though.

 

[NBE]

Re: Foam Technique

I think it is much easier to do the foam before installing the floor. As Ondarvr said, much easier to see what you are doing and to make sure that the foam goes where it is supposed to go. It is easily trimmed to be even with the tops of the stringers or however high you need it.

You also don't have to worry about resealing the holes or plugs that you cut out in the floor. Although fairly easy to seal them, I would always worry that somehow water may find its way under the floor through them.

That's my 2 cents worth.

 

[calwldlif]

Re: Foam Technique

I have done it both ways(puttin the foam)
I prefer using a peice of flooring not
fastened down. cut hole pour foam
lift floor inspect. re do, untill full.
Coat hull area with expoxy(not cured but wet)
pour foam, seal foam with more epoxy resin
when compartment is full. place flooring down
and seal

 

[Tail_Gunner]

Re: Foam Technique

Good points made there however i tend to go with another thought By pouring the foam after the top is on you will get the following benefits.

1. when foam complete's it's drying or curing process it adhere's or bonds to both the hull and the floor and being urethane that bond is incredibly strong, this not only strength's the bond between the two but it also "SEALS" both and i believe seals its self. If you let some foam expand and cure in the open you can see the seal (shiny&hard finish) if you then cut the foam you will notice it becomes porus not good. Now if you foam first your going to lose all of those wonderful attributes.

2. Foaming a floor with the cap on may seem hard but it is really very easy, In my rebuild what i had done was to attach the floor to the center stringer's, left the outside edges open. Next i took a chalk line and snapped a line around the peremiter took a 1/2" guide and attached it to the side

What takes place the foam pushes up the floor to the guide you see and then escapes out the sides

The result is a well compacted foam and i just took the old angle grinder and cut out the foam that was or would interfere with bonding or sealing the floor using peanutbutter (I left @ least a 3/8 inch gap between the floor and the side that is where the foam released any potential stress)

You might want to stagger your holes as such

so you can assure yourself maxium coverage and preventing any blow outs. 8) The hair dryer you see was used to make sure the air and the hull were at least 85 degrees that is critical for proper expansion rate (dont assume its 85 degree's and you hull will be that too.)

There are several reason's why i advocate this so strongly, both were first time mistakes but were very illumnating.......... one was i had not watched how far the foam had expanded on one pour (see the dip)

see how that floor dips, i had not expected the foam to migrate that far and it did bonding to a srip say 6" long and 2" wide we were not able to seprate the floor from the foam, we even tapped in two lag bolts screwed them into a chain and my two 200lb kids could not yard it off. With a whole floor bonded in such a fashion how can you go wrong there?

Secondly on the fianl pour of the night i had spilled a 16 oz beer :'( unkowningly) and began the pour, the foam literally pushed the beer out the sides of the floor 8) nope i did not salvage it. (beer that is) Now if it can push out moisture i would like to see some get in after it's cured....:devil:

All in all you have to do what you think is best but if done right foaming with the floor in, is in my opinion the right way............. and as to strength 8lb is really great stuff, until you foam a boat and then stand, jump or what ever on it, feel the rigidity, no gain in weight, how can you go wrong.......

 

[calwldlif]

Re: Foam Technique

I did forget the part about
putting plastic under the floor board to
keep it from being "stuck" down.
I still believe in using epoxy to
"waterproof" the foam. Encapsilate if you will.
Foam is closed cell but then why does it
get water soaked? tail gunner is right about the
compressing componant, thats why I place the floor down. I would only add my desire to encapsolate
the whole area in a water proof way.

 

[Terry Olson]

Re: Foam Technique

Not that I have much to offer - but - the factory original foam in my '83 Lund was poured and trimmed flush before the floor was installed. I re-did the entire boat last winter and was concerned that by trimming the foam the cells were open and would absorb water. I found the original foam to be dry as a bone and was surprised that even after hosing the debris out of the boat the foam DID NOT absorb any water. Apparently the cut cells are compromised but those below are not. I didn't have to replace the original foam.

What I take from this is that trimming the foam before installing the floor doesn't have any adverse effect on the foam's propensity to absorb water but I wouldn't have believed it before having this experience.

I'd foam, then install the floor but only because you know that all of the voids are full and you don't have to seal the holes or worry about overfilling. The idea that foaming after the floor is installed and the strength gain made when the foam bonds to it is definitely something to consider.

 

[studlymandingo]

Re: Foam Technique

Gees tailgunner... you wasted good beer?:$

 

[Tail_Gunner]

Re: Foam Technique

o Damm good thing it was late and i was tired a salvage attempt might have take place...........

 

[imported_John_Galt]

Re: Foam Technique

Thank you every One!

I like tail Gunner's approach the best. My greatest concern i using this method is refilling the holes but I plan to resin coat and glass in the deck too. So filling the wholes with the cut-outs and epoxy should do the trick.

TG how is the guide attached to the side? My side walls are all glass(covered with Carpet).

By the way spilling the beer was Alchohol Abuse.

John

 

[Tail_Gunner]

Re: Foam Technique

There screwed into those side walls you see, if you are going this way really take the time to align your string line to the tops of your stringer's. It seemed all so simple @ the time and i misaligned one side by 1/4 of " over a 4' lenght ...........small yes but it does tend to........:devil: off.

 

[bigbad 4cyl x2]

Re: Foam Technique

i glased mine all in . then drilled holes then raised bow and poured . worked great . get some paint mixers you can attach to a drill . a few of them . i went to a gas station and got the paper funnels they give you for free to put in oil . i used a big stack . and i got the plastic paint tubs and marked them with a marker . you will see build a supply list . i also used the foam from us composites and it worked great. . i think two pound foam would have been good enough . but i used the 4 lb stuff for more rigidity.

 

[imported_John_Galt]

Re: Foam Technique

Well I guess I'll need to find a way to anchor (great nautical word huh) my guide. I wish I had known about us composites before I bought the evercoat product (man was it expensive).

Sounds like this stuff starts to foam pretty quickly. Did you find that you made a number of pours in each hole?

Can you guys tell me how many sets of PART A & B you used for your boats. Mine is an 18 foot Celebrity Bowrider.

Thanks again

John

 

[ondarvr]

Re: Foam Technique

The warmer it is, the faster it foams and the more it expands, so you need to work fast.

Depending on the size of the area you are filling, you may need more than one pour per hole.

It's hard to say how much you will need, some boats have lots of open space under the floor that needs to be filled and some don't

 

[bigbad 4cyl x2]

Re: Foam Technique

id return the evercoat if you can. ,,id mix about 1 part of each of those cans in a bucket. those are small cans

 

[Tail_Gunner]

Re: Foam Technique

If your using 2lb it should expand 8/1 or expand 8 times its original size, 4lb is 4/1 8lb 2/1 that is US composite foam specs,,,,,,, Id try and find out the rate from the mfg for the foam you are using.

 

[Realgun]

Re: Foam Technique

When I foamed mine I tiped the boat bow high. I put the floor piece in the rear then poured the foam. then when I saw foam where the next floor piece needed to go I put down the next floor section and poured in that cavity. The last piece was tricky. I placed the foam into the areas, there were two and then slamed the floor into place. It leaked a but under the floor but its in solid and there are no holes in the floor. I know the areas are full as the foam leaked out from the edges a bit.

For the four box areas of floation I used the hole method. Bayliner did not fill these full, I did.

I used 16 cubic feet.

 

[Tail_Gunner]

Re: Foam Technique

I had thought of going that way also, But what i ended up doing was to completely level the boat. On the intial pours i dumped quite a volume of resin into shall we say void. Hoping in liquid form it would find all the low spots and start expanding up and out from there. (the resin will start curing with in 45 secs you need to mix for about 10/15 secs only and make a massive dump) As the foam began to cure i would block off the ports those being closet to the center stringers(old plywood scrap) you see and watch it expand to the port's closest to the side wall. (you could see the floor lift as it progressed outward's) Giving the first pour about 20 mins to cure i came back to the outer ports and again made a large pour about a gallon i believe, again blocking the ports with scrap wood and waiting and watching for the foam to start coming up the outer wall's. when that happened i released all the ports and there was overflow coming from most of them. 8) There were a few tense moments as i was listening for the floor cracking or make sound's of strain but it never happened.

From there i did go back to all the ports and if the foam was not up to the hole of i could see there was a little void there i would again pour the resin after a 10 sec stir in small quantities (1-2 cups) into the port and it wouild find its way to any valleys or void's, one port took 3 cups before it finally sealed.

I really dont want beat this up to much, but if you go this way make real sure of getting that stuff in quickly so it can find it's way to low spot's in a liquid form. Cause when it takes off it really start's expanding and gravity is meaningless @ that point.

 

[imported_John_Galt]

Re: Foam Technique

Thaks a agin fuys. I couldn't ask for better info from anywhere else. This site is terrific and you are all very kind to help out a newbie.

I am working on my stringers this week end and hope to pour foam within 2 weeks. I will be sure to let you all know how it is going.

Thanks again.

John

 

[imported_John_Galt]

Re: Foam Technique

Well I finally got it done.

I used the evercoat foam that I bought first and then ordered what I needed for the remaining pours from US COmposite. I would have to say the evercoat though more expensive, expanded better therfore covering more area than the US COmposities brand.

I screwed the deck down and left the sides open (where I would later glass to the side of the boat. The faom did a great job once I figured out how much to mix.

I filled the wholes with the drill outs from the hole saw and epoxyed them in. Now I just need to carpet and put in my seats.

Thanks to all who provided advice. It is truly appreciated.

John