# Pouring Foam



## DuckNut (Apr 3, 2009)

Don't do it.

If you are going to use this stuff you need to see what is going on with it. If you mix it incorrectly the stuff may attack itself and start to disolve itself and just end up with a glob of goo in the bottom.

Do it before you put the sole down. Mix, pour and trim. I found a guitar sting works great as a saw - get one that has the center strand and then wrapped with another - cheap too. After that coat the top part you cut with epoxy.


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## firecat1981 (Nov 27, 2007)

I agree, don't do it. The foam keeps expanding sometimes for a few hours depending on the temp. But even though it is still expanding it is also hardening. So if it hardens before it finished expanding then it can buckle the floor. The hole in the sole is only good for initial expansion. 
Just do smaller batches and wait till one is hard before your next pour. You might be surprised how much it expands.


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## oysterbreath (Jan 13, 2009)

"interesting" as written by yours truly doesn't imply that i'm interested in doing it that way. Thanks for the heads-up though. I do appreciate it. His specific case is vastly different than mine. His sole cavity is very deep where as mine is wide and shallow. In my case the foam would kick and clog vertically before really filling out with full width of the chamber. It would be a fiasco for sure.


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## Creek Runner (Sep 1, 2011)

When done right it's perfectly okay. Take a look at my build pics notice the holes in the floor covered over with glass? Yep that's the way mine is/was built.


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## blittle (Jun 3, 2012)

It can be done.  I'd avoid it if possible.  I've had foam just shrink up weeks later.  On this stage if you have time do it open and let the foam sit for a week or two just to make sure it's not going to turn soft and rubbery.  

One thing I've done on my last two builds is open pour and then do a second light pour on the sole and foam/stringers to actually bond the sole/cockpit floor to the foam/stringers.  

I've done it with rollers actually painting the 2 part foam on before it expands.  It will take 2-3 people and things must be right as you have one shot.  Practice on small pieces on the side.

But what happens is you will create good bond as the thin layer of foam expands and cures to the two pieces.  Obviously you'll need a good supply of weight to keep the expansion to a nil.


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## jms (Apr 21, 2011)

> Don't do it.
> 
> If you are going to use this stuff you need to see what is going on with it.  If you mix it incorrectly the stuff may attack itself and start to disolve itself and just end up with a glob of goo in the bottom.
> 
> Do it before you put the sole down.  Mix, pour and trim.  I found a guitar sting works great as a saw - get one that has the center strand and then wrapped with another - cheap too.  After that coat the top part you cut with epoxy.


this is good advice

i had to watch that video - a few observations:

the gentlman's breathing ? anyone notice that ? wonder how many ciggs a day that guy's sucking on ?

tools ? using a holes saw that size,to make the holes through the plywood - with a battery powered drill ? 

not sure what that wood is,i did notice a few large voids in the end grain of the hatch cutout - marine grade ply will not have voids,i also noticed the end grain has been left unsealed
i'm going to assume this cat is gonna pop the hole plugs back in,pop some glass over them ?

pouring foam - i've witnessed it blow out laminated deck sections - a friend,a know it all friend,used the pour in technique - he discovered th power of expansion...

not sure what the plan is with foaming ? using it as flotation ? 
a better plan may be to use the large blocks of foam,like the style for dock floats - just cut the foam to fit...much easier...

let me add this as well:

drainage - no matter what -wateris going to find it's way in the bilge area.with foam poured in,you can't control where this foam is going,if you made drain tubes/limber holes,the foam added in that manner will block the drainage - end result,water trapped...

keep all these things in mind...


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## DuckNut (Apr 3, 2009)

All post warn about affecting the sole. What if your hull is the weak link?


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## jms (Apr 21, 2011)

> All post warn about affecting the sole.  What if your hull is the weak link?



just like a chain - the weakest link fails...

usually,the weak link is the bond between the deck and the stringers/grid work...


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## Creek Runner (Sep 1, 2011)

I did say when done right!

http://www.bostonwhaler.com/page.aspx/pageid/148014/videos_why-whaler.aspx been doing it since 1959

Also isn't the Hobie Power skiff built the same way? Which has been highly reviewed on this forum.

Just because someone does something that doesn't know what they are doing doesn't make it a bad. Just like wood boats, as discussed on another thread wood isn't the problem it's the people who don't know what the heck they are doing that give wood a bad name.

My boat that is currently being built had the floor foam injected, the hull was still in the mold and there was ample relief holes for expansion. The foam was measured and mixed properly with the correct amount being used. My floor didn't pop lose, it's didn't bow up, my hull didn't crack. Anything can be done the wrong or right way!


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## jms (Apr 21, 2011)

you're absolutley correct

the problem kicks in,when people get in over their heads - people often make the mistke "believing their skills are far greater than what they truly are"...


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## DuckNut (Apr 3, 2009)

There are a lot of manufacturers out there with thousands of dollars in precision injection machines to accomplish this and yes, it can be done right.

The video shows exactly what is not right and I can guarantee that every bit of air space is not filled.

I guess I will use a quart in this hole and add more later is not doing things right. I did not see or hear where the guy used any calculations to determine the volume of space to be filled or the amount of foam needed to fill the entire cavity. I only heard - I had to drill another hole...

The video is a poster child of how not to do it and should not be used for a tutorial on how to do it right. In fact, he even showed a piece that was mixed incorrectly and that entire pour will turn to a sticky goo at the lowest point of the cavity, totally negating all efforts of his intended process.

We gave oyster opinions based on his post and his attached video. If he wants to spend a ton of money on injection equipment then it would be an improvement over pouring before the sole is on. But we did not gather that reference from his post(s). If he did buy the equipment he still would not want to use that video as a tutorial.


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## Creek Runner (Sep 1, 2011)

> There are a lot of manufacturers out there with thousands of dollars in precision injection machines to accomplish this and yes, it can be done right.
> 
> The video shows exactly what is not right and I can guarantee that every bit of air space is not filled.
> 
> ...


Yeah I have watched all of that guy's videos he doesn't do anything how I would do it inthe rebuild including using wood as a core! But that's neither here nor there, I never said what he did was the correct way of doing it.

"I said when it's done right" also you don't have to inject foam for it to be done right. You don't really think they were injecting boston whalers back in the 50's & 60's probably not even the 70's or 80's. I was just giving him another opinion than it's wrong. When in fact it can be done right injected or poured. No different than a wood boat can be built right or wrong.  

Let me add this is my opinion from my years in the marine industry, and by no way am I telling any of you that your opinion is wrong. I respect all of your opinions!

Tight lines


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## oysterbreath (Jan 13, 2009)

> you're absolutley correct
> 
> the problem kicks in,when people get in over their heads - people often make the mistke "believing their skills are far greater than what they truly are"...


Bingo dude! That's why i've been tippy-toeing threw my build. I ain't got a darn clue what i'm doing!lol


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## cutrunner (Jun 8, 2010)

Good gosh if its that hard to figure out and you need a million dollar machine to do it, just cut blocks of foam to fit like previously mentioned


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