Leaking bow air bag?

In buying used kayaks I often get spray skirts and sometimes float bags and paddles too. But one float bag I got has a fixture (that is glued into the bag for the air hose to attach) which has a glue joint which is now loose and leaking air. I have in mind to get a small syringe and fill it with Lexel to force some into the joint and let it set. I hope doing that will repair it and then I can use it again.
But before I do I thought I’d ask if any other product would be a better glue to use. Has anyone else done such a repair and what is the recommended way?

Just coat the valve with Aquaseal.

Sometimes Aquaseal will work, sometimes not.

If the bag has a Roberts valve on a vinyl stem with an internal flange that was originally bonded to the inside of the bag material, my experience has been that the joint will continue to fail no matter what or how much you apply to the outside of the stem.

I have repaired about a dozen old lightweight nylon Voyageur flotation bags with joints of that type using vinyl adhesives but it is a frustrating job because you have to get the adhesive inside the bag and then support the flange in approximation. Sometimes there is a larger dump valve nearby that you can work through. Too much vinyl adhesive containing acetone or MEK can start to dissolve a vinyl filler stem, however.

If you ever have a float bag that has holes that are beyond repair, cut out the filler valve along with a generous circular flange of bag material. That can be used to replace a filler valve and stem that you cannot otherwise repair on a functional bag.

It might help if you posted a photo of the bag and the location of the leak.

Willowleaf is correct. Aquaseak fixes everything. I can’t imagine a stronger or tougher glue.

This is the type of bag I was referring to. The small Roberts valve on a stem has an internal flange that is bonded to the inside of the nylon bag. You can see the outline of the flange on the outside of the bag.

With a lot of bags like this the adhesive bond of the flange inside the bag breaks down over time and the flange starts to separate. You might be able to plug a very small leak for a time by applying Aquaseal to the outside of the bag where the stem meets the fabric. But unfortunately once the bond of the flange to the inside of the bag starts to break down it continues to do so, eventually resulting in the entire stem coming loose if not repaired.

Applying Aquaseal to the outside of the bag and the stem will not prevent that and will often make it more difficult to try to bond the stem flange back in place. And yes, I have tried to repair leaks of this type with Aquaseal with only temporary success.

I am very familiar with Aquaseal. I have used it countless times to replace dry suit gaskets as well as seal small holes in dry suits and in flotation bags for which it works very well.

I would fold that bag in half along the axis of where the stem valve is positioned and cut out a circle to excise it from the bag. Then you can apply a solid patch over the resultant hole and salvage the bag. if you want to retain the stem valve option, you can get a fresh “top off” valve from DIYpackrafts.com and use the large hole you cut to be able to apply glue to the inside of a new opening somewhere else on the bag before you slap the patch on the big hole where the old valve was.

Having used float bags for 20 years (got my first skin on frame in 2002) I have a lot of experience patching flotation and inflatable sponsons, as well as years of patching up the whitewater rafts my outdoor club nursed though many seasons back in the 1970s through 1990s. A well applied patch is the toughest part of any inflatable. Sometimes you have to inflict a little more temporary destruction to facilitate valve replacement.

even my best air bags are blow-n-go. Much like someone driving after a dui, I have to blow every time I go. The good news is I have an endless supply of hot air. As far as patching goes, I’ve gone the aqua-seal route. I’ve put on so much I’ve had to take the valve back off to get it to work, only to have it leak again. Did I mention I’m a fan of inflatable monkeys?

It is important to have a small Roberts valve on a stem on canoe flotation so you can top off the bags after you put on. A bag will lose up to 20% of its volume very quickly after you put the boat in cold water. The big circular valves are fine for filling and emptying the bags, but no good for topping them off. So getting rid of the valve is not a good idea for canoe flotation at least. Also not a good idea for bow bags in front of a bulkhead in whitewater kayaks since the only easy way to inflate them or let air out is via a valve on a long stem.

Certainly if you have a replacement filler valve either purchased new or cut from a deceased bag you can cut out the existing valve and bond the replacement in place, probably to the exterior of the bag. For that purpose Aquaseal would probably work as the bonding agent.

I have repaired leaking top off valves on at least 20 old Voyageur nylon bags which date back to the 1980s. All of which I still have in use using the method I described without the need of a replacement valve or cutting up an old bag. The type of valve stem pictured is vinyl and I have had better luck getting a good bond with vinyl adhesive than with Aquaseal. Vinyl adhesive also provides an immediate tack bond, which Aquaseal does not, which helps hold the stem valve in the correct position as the adhesive hardens. It takes a bit of practice to do this, but it works.