# Internal tube sealants



## OregonRafter (Jan 30, 2013)

I tried the 2 part urethane, that you pour in through the valve hole, on a raft to fix many pinhole leaks in the tubes. The hard part for me was getting the urethane to coat the wear spots where the holes were on the top of the tubes and on the inside compartment sections of the tubes. It didn't seal any of the pinholes and in considered it a total waste. I would have been better off spending the money on glue and material for conventional patches. Maybe I did something wrong or the holes were just in difficult spots for the product to work correctly YMMV. If I were to attempt something again I would instead consider a paint on system. But this only buys time on an otherwise pretty beat up raft.


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## theBoatPeople (Jun 19, 2012)

We've had mixed results with it too, though the only two we had done much with were Inland Marine and a pink latex/ammonia base product. It definitely will not work on the one i.k. you have with talc inside. It seems to work the best with rubber boats that have clean interiors, and the urethane version might work better for pvc - though again, no first hand experience with that product. 
Old ProAdvantage/Legacy boats also had a weird rubber on the inside that repelled sealants. What brand(s) do you have? If you try it let us know how it goes.


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## slickhorn (Dec 15, 2005)

had good luck using whatever material maravia uses. used on both urethance and hypalon boats. 

pull valve, spray with 303 for easier cleaning. put 1 qt in each tube, replace valve, lightly inflate, keep boat moving to coat. wet vac out excess. use a big red blower to keep air moving in the chamber til dried. 

its a chore.


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## kikii875 (Oct 25, 2010)

I used the NRS flex seal on a boat three years ago and it is still holding. I used more than what was recommended to make sure I got it coated well.
As far as the one with talc, it is not going to hurt it to flush it with water and then dry it before you use a product. If it was me I would half fill the tubes with water and move them around a lot to make sure I got all the talc, then drain the water out and repeat. Then to get the inside dry I have taken a leaf blower and duct taped a pvc pipe to it with a small enough diameter to fit in the valve hole with the valve removed. You can maneuver it so the pvc is at one end of the section and then the other and let that thing crank for a few hours at each spot. The air will circulate and pick up the residual moisture and come out the gap in the valve hole around the pvc pipe. Just keep doing that until all the moisture is out. Then use whatever product you decide upon.
FWIW
Tom


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## pearen (Apr 28, 2007)

I used the raftsmith urethane on a maravia urethane boat. Proj took a bit and definitely needs to be done outside for ventilation unless you have a spray booth. But it wasnt too hard. Worst part is wrangling the inside the tube part of the valve back into place. Wear nitrile gloves or similar. You really don't want to touch or breath the stuff.

It worked. It was two seasons ago and durability seems good so far. I had some pinholes that it worked 100% on and some big (+18" gouges that leaked) scratches through the spray booth urethane down to the cordura that it did ok on. I did not put it in the dropstitch floor based on recommendations on this forum, but I am considering it seeing as the tubes went well and its a 15+ yr old boat.

How bad could it be? What could go wrong?


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## mikepart (Jul 7, 2009)

pearen said:


> I used the raftsmith urethane on a maravia urethane boat. Proj took a bit and definitely needs to be done outside for ventilation unless you have a spray booth. But it wasnt too hard. Worst part is wrangling the inside the tube part of the valve back into place. Wear nitrile gloves or similar. You really don't want to touch or breath the stuff.
> 
> It worked. It was two seasons ago and durability seems good so far. I had some pinholes that it worked 100% on and some big (+18" gouges that leaked) scratches through the spray booth urethane down to the cordura that it did ok on. I did not put it in the dropstitch floor based on recommendations on this forum, but I am considering it seeing as the tubes went well and its a 15+ yr old boat.
> 
> How bad could it be? What could go wrong?


Don't do it. The drop stitch floor has a million little threads inside. The urethane will glue them all together. I don't say this from experience with internal sealants, but I have definitely seen the inside of drop stitch and I strongly advise against putting anything adhesive in there. Do a google image search for "drop stitch inflatable" and you will see what I mean.

Of course, if you do try it, post the results here


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## mikepart (Jul 7, 2009)

Thanks for all of the responses and keep 'em coming if you have a story to tell or information about this stuff.

BTW, in my opinion THIS is what Mountain Buzz is for.


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## DoStep (Jun 26, 2012)

pearen said:


> ....... I did not put it in the dropstitch floor based on recommendations on this forum, but I am considering it seeing as the tubes went well and its a 15+ yr old boat...



What kind of boat? 

That goes for all posters who have tried this method please!

Yes this sounds like a real chore no matter the boat type.


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## pearen (Apr 28, 2007)

Considering using the two part Raftsmith Flexseal Liquid Urethane on a standard Maravia urethane dropstitch floor. I understand the nature of the dropstitch floor and I know I could glue it together. Basically, what I am banking on is this stuff does not stay sticky/tacky in the tube for a long period, but instead cures over about 48 hours. If I keep the floor lightly inflated for those 48 hours, plus a healthy margin, then it should be good to go. Please don't tell me not to do this unless you have tried and jacked your floor up. Anyone?

And yes, I will post the procedure and results if I go for it. Hell, I will even measure/check the leak rate before I try it so we can quantify the benefit.

I think the point I was trying to make is...Its really not that hard, <10 min per chamber, just be careful not to touch or breathe the stuff.


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## bdf48 (Mar 4, 2010)

I hear the West Marine Inflatable boat sealant works well. 

WEST MARINE Inflatable Boat Sealant | West Marine

I boat a bottle of this and plan on using it on an old avon that I have.


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## reynard (Sep 13, 2021)

bdf48 said:


> I hear the West Marine Inflatable boat sealant works well.
> 
> WEST MARINE Inflatable Boat Sealant | West Marine
> 
> I boat a bottle of this and plan on using it on an old avon that I have.


How did that work out?


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