Wing bladder pinhole repair tip

[UnusuallyLargeRobin]

Hey everyone, Here's a tip to locate very small leaks in wing/kite bladders. I've recently had to repair 4 very tiny tiny pinholes in my wing strut bladder. Let me tell you finding them was a bugger! I first noticed my wing strut would get soft after an hour or longer, not catastrophically soft, still able to wing but noticeable degradation, pretty much limp if left overnight.

So, I pulled out the strut bladder and began the hunt for leaks. I pumped up the bladder very lightly, otherwise it will grossly distort the shape at any significant pressure, and again could find no visible areas of leakage (even with magnifying glass) on the strut or with usual suspects of inflate valve and dump valves. Same for trying to listen for any leakage. Getting frustrating! Going to the soapy spray bottle test, gently massaging/squeezing the strut bladder and still no obvious leaks which usually show up with soapy bubbling action. I assume the air pressure was insufficient to cause a bubbly leak with these little buggers.

OK, put the bladder back into wing and pump it up to maximum designated pressure. Begin to spray all over the wing to try and get a general fix on the area I should focus on, and voila, soapy bubbles are coming from a few spots near the rear handle and toward canopy from it. Pull out the bladder thinking I've got the 1 sq.ft area to look at and again can see nothing obvious even with magnifying glass and again not enough pressure to get any soapy bubble effect to show me where the holes are. These things are so small you can't see them, they look like any other miniscule imperfection using a magnifying glass and you get no audible air or soap bubbles from them at low pressure. Very frustrating!

The TIP: I had my face and ear up against the bladder listening and I passed a spot that gave the slightest little feeling on my eye/cornea. Turns out, if you get your eye up really close it is sensitive enough to feel this little little little breeze and you can then focus on this little little little blemish to then slap a patch on the sucker and it's fixed! Yay!!
So in conclusion, to find these incredibly annoying miniscule holes, isolate the area with a soapy spray on the wing fabric with it pumped up to max pressure and it should show you the general area to search for on the bladder itself. With bladder removed, if the holes aren't obvious, jam your eye very close to the bladder and start moving slowly across the area and feel for the very light air pressure on your cornea. Once you feel the tiny breeze/pressure, you've got your micro-pinhole isolated and slap a patch on that thing!

Hope this helps you out when you encounter these super slow, hard to find leaks! Cheers ULR

[slake]

Made me think of a glaucoma test at an eye doctor...that is very noticeable, almost makes one jump out of their seat. Wonder what an eye doc would think of your bladder test? I'd assume it is pretty harmless. Nice work finding a solution!

[more force 4]

Thanks Robin, that is a great assist. I have to do both my strut and leading edge on my 4m, it gets noticeably soft after about 10 minutes and floppy in an hour. Was not looking forward to the frustration.

I was going to write that I had tried it and scratched my cornea, but I resisted the urge!

[joe mcbride]

I just did the strut and leading edge (LE) of my 5.0 Ocean Rodeo (OR) Glide. Here is how it went.

The strut was easy as I have done it a few times before. But the leading edge was a lot of work. My first clue was when I opened the tips of the leading edge and found grains of pink Baja sand . . .

With Ocean Rodeo the LE and strut are completely separate. I looked at Reece Myerscough's repair video for OR Aluula kites, and chose to use the same approach for my wing, pulling the whole bladder out, one side at a time, through the leading edge valve hole. I made sure to clean my garage floor beforehand, using a wet mop, so as not to get any grit or other debris on the bladder.

I had a spray bottle of dilute detergent that I use in my kitchen, so that was handy. I inflated the wing, took it out to the driveway, and wetted the whole leading edge with a hose, using a mist setting. I brought the wet wing back into the garage and sprayed it with detergent, bit by bit. Bubbles started appearing in spots, mostly near one wing tip. I marked the spots on the frame with a felt permanent marker, but more important was taking pictures of where the bubbles were. I rinsed the detergent off the wing with a hose outside, dried it, brought it inside and deflated it. I opened the frame at the tips of the leading edge and attached strings, taking pictures at every step. I pulled out the bladder, inflated it, and started spraying with detergent. Very cumbersome. An inflated bladder is in the order of fifteen to twenty feet long. Make sure to have bladder friendly items to stabilize the bladder as you work with it. It will want to roll to orient the valve downward.

I found no leaks at first. Then I decided to inflate it more, increasing the internal pressure quite a bit (about one foot diameter in the middle). That is when I found what I hope is the major (only?) pinhole, which looked suspiciously like a grain of sand. I deflated the bladder, flattened it, wiped off the detergent, cleaned the hole area with propanol, stuck on a small tear-aid patch, reinflated it, and sprayed it again, to check my patch and to look for more holes. I only found the one hole. There might be one in the other wing tip, but the bubbles were not nearly as angry.

I used a micro fiber cloth and water to wipe the detergent off the bladder - concerned that it might degrade it. I laid out the bladder flat on my shiny clean floor, and pulled both ends back through the valve hole, taking care to orient it properly. Very laborious. I did not want to pull too hard, for fear of damaging the bladder. I had to fiddle a lot to get the bladder settled in the frame, partially inflating it and then massaging it into place. Once it was back together, I closed the tips and inflated the strut to a low pressure and inflated the LE partially. Turns out I had pinched the bladder with the valve hole velcro, so it was lucky I did not put a lot of pressure in to start with. I deflated it mostly and made sure to get the bladder out from under the valve hole velcro. I reinflated it, again slowly with massaging to make sure the bladder was properly seated in the frame.

I tested the LE and it and it held well. All told I would say I spent five hours on the LE re and re. What a pain in the ass. As it turns out, the wind that was promised this evening did not arrive by 7 pm, so I treated myself to dinner out!

Joe