Closed cell expanding foam hand gun

[TEO]

Excuse the slightly garbled title.
Does anyone have experience of a closed cell expanding foam applied by a gun or poured?
Does such a thing exist?
The project (foam reinforcement + buoyancy in a dinghy) doesn't merit £500+ froth pack I'm wondering if any of the acoustic expanding foam or anything else exists please?

 

[carbon]

Most fibreglass suppliers will have a 2 part polyurethane closed cell pouring foam. Not sure of the quantity you require

2 part polyurethane foam

 

[Erie Fred]

Excuse the slightly garbled title.
Does anyone have experience of a closed cell expanding foam applied by a gun or poured?
Does such a thing exist?
The project (foam reinforcement + buoyancy in a dinghy) doesn't merit £500+ froth pack I'm wondering if any of the acoustic expanding foam or anything else exists please?

You don't have the "Can Foam" available ?

 

[TEO]

Most fibreglass suppliers will have a 2 part polyurethane closed cell pouring foam. Not sure of the quantity you require

2 part polyurethane foam

Thanks, that was going to be a call first thing in the morning, the data sheets for the ones I'd looked at didn't say.

 

[TEO]

You don't have the "Can Foam" available ?

Cheers, is that a brand or a generic term for expanding foam from a can?
We've lots of pu expanding foam in cans, two types of cans available; those that screw into a gun type dispenser and those that come with a straw. The second type rarely remain useable after a few hrs but great for small quick jobs used to be for the DIY market but often used by tradespeople who don't want to leave a can on the gun.
Anyway, I've still not found a closed cell pu expanding foam sold in a can. The pouring foam looks good but I was hoping for the easy option of dispensing from a can.
Cheers though

 

[Misterg]

Does anyone have experience of a closed cell expanding foam applied by a gun or poured?

Going back to basics:

Normally for buoyancy tanks, etc. one would use 2 part foam that's mixed and then poured into the compartment - like this:

CFS Fibreglass - 2 Part Polyurethane Foam - GRP Supplies

2 Part Polyurethane Foam

www.cfsnet.co.uk

Judging quantities is tricky: It goes from looking like there is nowhere near enough to there being masses too much very quickly. If you get it badly wrong, it can split the buoyancy tank (or whatever) due to the pressure. A lttle bit under can be topped up. A little bit over makes an unholy mess.

CFS guide gives an idea:

CFS Fibreglass - Pouring 2-Part Polyurethane Liquid Foam - GRP Supplies

Pouring 2-Part Polyurethane Liquid Foam

www.cfsnet.co.uk

You can also get closed cell foam in aerosols, but they're even more hit and miss (IMHO)

 

[Keith 66]

^^^^^ This is very true, At falmouth boatbuilding college we built a 15ft rowing dinghy for disabled use, she had a full length flat floor & was subdivided with two pack foam poured in some areas.
The bow tank was a triangular shape & we were asked to work out the volume by Simpsons rule, Mr Lucas our GRP lecturer checked our calculations then weighed out too much foam liquid, It was mixed & poured & then didnt stop, It came frothing out of the pouring holes & the boat & plywood deck started groaning. It burst the 12mm marine ply deck. Most impressive!
The RNLI & Navy used a foam with big cells that was supplied in block form, that was good stuff.
But 45 years in the boat trade have taught me that there is no such thing sold to the public as waterproof pourable foam.
All the others soak up water sooner or later, I have lost count of the times i have had to chop sodden mud filled, black, stinking, waterlogged foam out of boats, hulls & rudders. Its awful stuff & i will not use it anywhere its going to get wet.

 

[TEO]

Going back to basics:

Normally for buoyancy tanks, etc. one would use 2 part foam that's mixed and then poured into the compartment - like this:

CFS Fibreglass - 2 Part Polyurethane Foam - GRP Supplies

2 Part Polyurethane Foam

www.cfsnet.co.uk

Judging quantities is tricky: It goes from looking like there is nowhere near enough to there being masses too much very quickly. If you get it badly wrong, it can split the buoyancy tank (or whatever) due to the pressure. A lttle bit under can be topped up. A little bit over makes an unholy mess.

CFS guide gives an idea:

CFS Fibreglass - Pouring 2-Part Polyurethane Liquid Foam - GRP Supplies

Pouring 2-Part Polyurethane Liquid Foam

www.cfsnet.co.uk

You can also get closed cell foam in aerosols, but they're even more hit and miss (IMHO)

Thanks I'll have a look at that site & if you have a name for the closed cell foam in a can please I'd be very interested. May not be suitable for this repair but I've been looking for yrs & who knows what the next project will be.

 

[TEO]

^^^^^ This is very true, At falmouth boatbuilding college we built a 15ft rowing dinghy for disabled use, she had a full length flat floor & was subdivided with two pack foam poured in some areas.
The bow tank was a triangular shape & we were asked to work out the volume by Simpsons rule, Mr Lucas our GRP lecturer checked our calculations then weighed out too much foam liquid, It was mixed & poured & then didnt stop, It came frothing out of the pouring holes & the boat & plywood deck started groaning. It burst the 12mm marine ply deck. Most impressive!
The RNLI & Navy used a foam with big cells that was supplied in block form, that was good stuff.
But 45 years in the boat trade have taught me that there is no such thing sold to the public as waterproof pourable foam.
All the others soak up water sooner or later, I have lost count of the times i have had to chop sodden mud filled, black, stinking, waterlogged foam out of boats, hulls & rudders. Its awful stuff & i will not use it anywhere its going to get wet.

Sounds like very frustrating stuff.
Do you think the foam block used in RN & RNLI is the same as that used in kayaks?
Your experience sounds invaluable, I'm not wedded to the foam idea but as a total novice with epoxy, the gap filling properties of foam are attractive. Previous owners of my boat made an adjustment (dug a bloody great hole) in the cockpit sole that had it been done well would make good sense but as it is will just sink her! I'll see if I can take any pics that show the extent of the problem.

 

[Hood]

One thing is don't use the normal builders type foam, it will not stand up to salt water and will be mush in no time, quite a few fisherman have tried it and not one has had any success.
I have used THIS before and after 7 or 8 years it is still holding up well.
Usual warnings about getting your volumes worked out correctly or doing it in several stages, apply.

 

[TEO]

One thing is don't use the normal builders type foam, it will not stand up to salt water and will be mush in no time, quite a few fisherman have tried it and not one has had any success.
I have used THIS before and after 7 or 8 years it is still holding up well.
Usual warnings about getting your volumes worked out correctly or doing it in several stages, apply.

Yup, I don't think that any of the "normal" expanding foams are closed cell.
Keith 66 above is saying that pretty much any foam degrades.
I've been hoping that foam, expanding to fill gaps & difficult spaces will work in place of lots of tricky epoxy repairs, may just have to get to it with the epoxy.

 

[Robotstar5]

Reminds me of installing a foam pouring robot for a company that built car seat cushions, we were doing test shots into bin liners when the guy holding the bag suddenly ran outside, I asked the other chap what was going on, he said "a bin liner will hold a 4 second shot, that one was 6 seconds, if we go out, we'll probably find Dean in the middle of a cushion"

 

[Keith 66]

The old stuff that the RN & RNLI used for bouyancy blocks was a sort of Brown or Green foam, the cells were big & thicker walled. I doubt it is available today.
All the two pack polyurethane foams will absorb water eventually. Dell quay dories used to be foam filled, what happens is keelbands start to leak through screw holes as the sealant fails, water gets in & cant get out. The boat gets heavier & heavier, until you have no choice but to cut the deck out & start digging the crap out. It might take ten or fifteen or twenty years but that water will get in. On a wooden boat poured foam is the kiss of death. Its ok above the waterline for insulating fridges but thats it.
Last foam job i did was on our yacht. A Sabre 27 built in 1971, I had to replace the transom mounted boarding ladder as it was broken & this entailed bolting through the transom & cockpit moulding. Four holes drilled & water poured out & kept coming. It turned out that the entire transom was foam filled right up to the top. Arrrgghh! There was no option but to cut a large access panel into the inner moulding so i could cut the stuff out. A weeks work ensued, 30kgs of sodden wet foam was removed. I lost another two weeks with it drying before i could fix it.
All that water had gotten in via four fittings that had leaked, once in there was nowhere for it to go.
The only foam i have used that is actually waterproof is PET foam & i have used it for cores on stringers & foam sandwhich construction. It is not available in pourable form only in sheet or block.

 

[Misterg]

if you have a name for the closed cell foam in a can please I'd be very interested.

Just had a quick look, and I can't find anything at the moment - I'm sure that there used to be products that claimed to be closed cell (may have been isocyanate??).

(I'd echo the comments about the problems with the stuff getting waterlogged if it's allowed to get wet for any length of time.)

I've been hoping that foam, expanding to fill gaps & difficult spaces will work in place of lots of tricky epoxy repairs, may just have to get to it with the epoxy.

This is starting to ring alarm bells ... If there's something that needs repairing on a boat, then expanding foam is never the answer.


Show us some pics of what you're wanting to fix...

 

[TEO]

Just had a quick look, and I can't find anything at the moment - I'm sure that there used to be products that claimed to be closed cell (may have been isocyanate??).

(I'd echo the comments about the problems with the stuff getting waterlogged if it's allowed to get wet for any length of time.)

This is starting to ring alarm bells ... If there's something that needs repairing on a boat, then expanding foam is never the answer.


Show us some pics of what you're wanting to fix...

Not half as alarmed as I was once I fully understood the extent of the "adjustments" the previous owners had made
However, don't be too alarmed, I'll not put it back on the water until I'm satisfied with the fix. I'll not be using expanding foam unless I can find the right one, hence my original post.
Thanks for taking an interest, pics to follow.

 

[TEO]

The old stuff that the RN & RNLI used for bouyancy blocks was a sort of Brown or Green foam, the cells were big & thicker walled. I doubt it is available today.
All the two pack polyurethane foams will absorb water eventually. Dell quay dories used to be foam filled, what happens is keelbands start to leak through screw holes as the sealant fails, water gets in & cant get out. The boat gets heavier & heavier, until you have no choice but to cut the deck out & start digging the crap out. It might take ten or fifteen or twenty years but that water will get in. On a wooden boat poured foam is the kiss of death. Its ok above the waterline for insulating fridges but thats it.
Last foam job i did was on our yacht. A Sabre 27 built in 1971, I had to replace the transom mounted boarding ladder as it was broken & this entailed bolting through the transom & cockpit moulding. Four holes drilled & water poured out & kept coming. It turned out that the entire transom was foam filled right up to the top. Arrrgghh! There was no option but to cut a large access panel into the inner moulding so i could cut the stuff out. A weeks work ensued, 30kgs of sodden wet foam was removed. I lost another two weeks with it drying before i could fix it.
All that water had gotten in via four fittings that had leaked, once in there was nowhere for it to go.
The only foam i have used that is actually waterproof is PET foam & i have used it for cores on stringers & foam sandwhich construction. It is not available in pourable form only in sheet or block.

I can see why you advise against, sounds like a nightmare. Lovely boat though, have you still got her?
I'm grateful for the interest, I'll post pics later & welcome any more comments, can't promise to follow all of it but it is appreciated.

 

[Erie Fred]

Cheers, is that a brand or a generic term for expanding foam from a can?
We've lots of pu expanding foam in cans, two types of cans available; those that screw into a gun type dispenser and those that come with a straw. The second type rarely remain useable after a few hrs but great for small quick jobs used to be for the DIY market but often used by tradespeople who don't want to leave a can on the gun.
Anyway, I've still not found a closed cell pu expanding foam sold in a can. The pouring foam looks good but I was hoping for the easy option of dispensing from a can.
Cheers though

Is the can foam not closed cell ?

Yes, I have both types of can foam, a trick for the straw types, it to buy cheap carb cleaner.
As soon as your done, remove the straw, and spray carb cleaner (use the little red straw) all thru the straw,
and also into the can's fitting.

Have used them 6 months later if you clean the straw & valve on the can.

BTW keep the old cleaned straws for re-use.

EDIT: I have switched to this brand, does not break down in the sun, and does not contain large air pockets, much more consistent product.

Loctite Tite Foam Gaps & Cracks

Seal and insulate gaps & cracks up to 1” inside or out

www.loctiteproducts.com

 

[TEO]

Is the can foam not closed cell ?

Yes, I have both types of can foam, a trick for the straw types, it to buy cheap carb cleaner.
As soon as your done, remove the straw, and spray carb cleaner (use the little red straw) all thru the straw,
and also into the can's fitting.

Have used them 6 months later if you clean the straw & valve on the can.

BTW keep the old cleaned straws for re-use.

EDIT: I have switched to this brand, does not break down in the sun, and does not contain large air pockets, much more consistent product.

Loctite Tite Foam Gaps & Cracks

Seal and insulate gaps & cracks up to 1” inside or out

www.loctiteproducts.com

That's a good tip, thanks.
All the can foam that I've found is open cell though some is less open than others.... Some of the low expansion foam or acoustic foam claims about 70% closed cell; still 30% a sponge & unsuitable for my needs.

 

[Burdekin]

A good few years back we had what was supposed to be closed cell foam insulation for vessel insulation. I had suspicions the foam was holding water and thought it might be a safety issue on a hot vessel so soaked some in water and then heated it, it exploded as the steam couldn’t escape fast enough we assumed.

 

[TEO]

A good few years back we had what was supposed to be closed cell foam insulation for vessel insulation. I had suspicions the foam was holding water and thought it might be a safety issue on a hot vessel so soaked some in water and then heated it, it exploded as the steam couldn’t escape fast enough we assumed.

Good catch that, I hope your insight was recognised