Hi Guy's, wondering if you have any advice on fixing this bladder issue or if it is at all possible to fix?My Duotone Unit (V1- 2021) central strut popped right at the tip end. As the hole is very close to the end welded seam, I don't think patching the area would work well enough? Any advice or recommendations would be much appreciated.

Perso I would try to get a heat sealer unit and just do a hot line right across the bottom, next option is the patch, third option is tricky but works if you are good - a patch using nylon glue

I've used Tear Aid Type-A to fix blowout exactly like this. It works extremely well. www.tear-aid.com

I used tear aid to repair a giant blow out in my 7M glide, like bigger than 12". Upon testing, that repair held, but I blew out the end of the bladder just like in your photo due to improperly reinstalling it. I'd say go for the repair and test it in a more protected area for first session in case of failure.

I would go ahead and buy a replacement bladder now... try fixing this one, but chances are it wont take and you'll want the replacement bladder onhand so you dont lose time on the water.

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kiwiupover said..
I would go ahead and buy a replacement bladder now... try fixing this one, but chances are it wont take and you'll want the replacement bladder onhand so you dont lose time on the water.

Sounds like a good plan.

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foilthegreats said..
I've used Tear Aid Type-A to fix blowout exactly like this. It works extremely well. www.tear-aid.com

Thanks. Will order some Tear Aid and give it a go.

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sultanofwing said..
Perso I would try to get a heat sealer unit and just do a hot line right across the bottom, next option is the patch, third option is tricky but works if you are good - a patch using nylon glue

Thanks for the vid. I was thinking of trying my own version of a heat seal using a soldering iron at a test point.

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Hanns said..

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Thanks for the vid. I was thinking of trying my own version of a heat seal using a soldering iron at a test point.

I've just finished doing some major repairs to a wing, including re-welding the bladder. The strut got hit by the foil in a big shore break splitting the fabric and the bladder exploded with a 30cm split down one seam with a bit of an L-shape at the end.

I welded the strut with a household iron. The first go was a bit wonky but the second go is beautiful. The wing holds pressure overnight at 8psi and I've done two sessions on it.

The basic process is:
- domestic iron on the lowest part of the highest heat setting. You'll have to experiment to work out what works best.
- I used baking paper to stop the iron sticking to the bladder, and bladder to bladder where necessary. You can use ordinary printer paper but baking paper is translucent so you can see though it a bit.
- I used a wooden straight edge to keep the weld straight and neat.
- Be really careful that you don't accidentally touch any part of the bladder that you don't want to weld. It makes nasty holes.
- Run the iron fairly quickly and smoothly over the part to be welded. If it's worked it will have welded. It's fairly obvious that it's worked. If not do it again. Vary the speed of the iron to get more or less welding effect. Also bias the iron so you're using a little bit of edge.

For the L-shape I put baking paper inside the bladder, pulled the bladder material over the L-shape and welded it. I took out the baking paper then set up the straight edge to and welded down the seam. It makes the bladder a little narrower but that's not a problem.

I ended up with a slow leak at the tip of the L where the fabric overlapped. I rubbed some urethane glue on the leak but I think it's still leaking. It loses 2psi over 12 hours so that's not really a problem.

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Gorgo said..

Hanns said..

...

Thanks for the vid. I was thinking of trying my own version of a heat seal using a soldering iron at a test point.

I've just finished doing some major repairs to a wing, including re-welding the bladder. The strut got hit in a big shore break splitting the fabric and the bladder exploded with a 30cm split down one seam with a bit of an L-shape at the end.

I welded the strut with a household iron. The first go was a bit wonky but the second go is beautiful. The wing holds pressure overnight at 8psi and I've done two sessions on it.

The basic process is:
- domestic iron on the lowest part of the highest heat setting. You'll have to experiment to work out what works best.
- I used baking paper to stop the iron sticking to the bladder, and bladder to bladder where necessary. You can use ordinary printer paper but baking paper is translucent so you can see though it a bit.
- I used a wooden straight edge to keep the weld straight and neat.
- Be really careful that you don't accidentally touch any part of the bladder that you don't want to weld. It makes nasty holes.
- Run the iron fairly quickly and smoothly over the part to be welded. If it's worked it will have welded. It's fairly obvious that it's worked. If not do it again.

For the L-shape I put baking paper inside the bladder, pulled the bladder material over the L-shape and welded it. I took out the baking paper then set up the straight edge to and welded down the seam. It makes the bladder a little narrower but that's not a problem.

I ended up with a slow leak at the tip of the L where the fabric overlapped. I rubbed some urethane glue on the leak but I think it's still leaking. It loses 2psi over 12 hours so that's not really a problem.

Thanks Gorgo. I will give it a go.

I know of quite a few (including 2 punctures of my own), for that particular model Unit wing. See pics below

My 3.3m and 5m Unit had the same puncture as yours. My 3.3m was brand new, and hadn't even touched the water yet. It was a known problem. I got 2 free replacement bladders from Duotone and others I know of also got a free replacement bladder. So ask your shop before you bother fixing it.

Check when you close the end of the strut, that the Velcro is fully covered up with the corresponding Velcro. Otherwise there is a sharp edge in there. A few of us thought maybe the Velcro was cutting into the bladder in the Units.
Aaron.

Just a little addit. to Gordo's helpful advice:
I like to open the end of bladder and patch the inside as well, using baking paper to avoid sticking both sides of bladder together. This helps in getting the trimmed-up hole sitting nice and straight before applying a second patch to outside. And will reinforce the area; just have the edges of each patch in different places.
Then reseal the end of bladder.
Unless the bladder was incorrectly installed, there must be some other reason why it blew out there. consider adding something like Velcro to the end to keep it in place. Also, consider adding a chunk of soft foam (eg: 4 or 5cm length of swimming pool noodle) within tip of strut sleeve to reduce the space the bladder has to expand into. I think sometimes manufacturers underestimate how much that bladder must stretch out to fill in the 3-D space. You might even attach the foam to the bladder end before jamming it into the sleeve.
Note: If you use Sultan's preferred method above, you'll definitely need packing in the end of the sleeve, as the bladder would be shortened somewhat.

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ARichards said..
I know of quite a few (including 2 punctures of my own), for that particular model Unit wing. See pics below

My 3.3m and 5m Unit had the same puncture as yours. My 3.3m was brand new, and hadn't even touched the water yet. It was a known problem. I got 2 free replacement bladders from Duotone and others I know of also got a free replacement bladder. So ask your shop before you bother fixing it.

Check when you close the end of the strut, that the Velcro is fully covered up with the corresponding Velcro. Otherwise there is a sharp edge in there. A few of us thought maybe the Velcro was cutting into the bladder in the Units.
Aaron.

I suspect they're not allowing enough extra length of bladder? The uninflated bladder is flat, so needs a fair bit of surplus length to enable it to open up into quite a broad 3-D tube without stressing it.

Widthwise stretch shouldn't be much of a problem. The bladder material has heaps of stretch in it and mine have way more material than it needs. When it exploded there was a ball the size of a large basket ball sticking out of the hole in the strut. Not sure about lengthwise stretch, the seam running the whole length might restrict the amount of stretch you get.

Most kite and wing tips have nice soft fabric and it bends back on itself away from the bladder and hooks onto velcro. Unless the design is weird there's no way the inflated section of bladder could come into contact with velcro. The tip of the bladder is usually folded inwards in thirds so you have 6-8 layers of non-inflated bladder material in the tip.

Bladders should only be about $50-60. I only repaired mine because of the learning experience. I already have a spare (Switch sent me full sets of bladders for two wings after a long running valve peeling problem) but it's fun, and surprisingly successful, to DIY repairs.

The wing had 150 hours on it and was the first one I bought as a learner. The repaired strut bladder has a bit of a bulge up near the leading edge, a couple of other bulges and abrasion and distortion near the handle reinforcement straps, and the bulge from where it exploded. After my repairs there's all sorts of stitch lines inside the strut which I expect won't do it a lot of good. I am curious to see how much of a hammering a repaired old bladder can take before it fails again.

I love reading all this info about bladder blowouts I have a SIC Maui blew out also low down on the center strut, I spent some time analyzing the pocket sleeve housing and finally modified it with my 1970's sewing machine, patched and replaced in the now tighter, narrower sleeve, no probs since but still wary of course