Leading Edge blowout repair - A view from Thailand
1 Urathane Glue and PVC patch (cut from a childs inflatable ring)
My go to method. In tropical climes do in AC room to remove some moisture and heat as this increases the glue working time or mark out an do quickly. Dont apply to much weight to the joint as this is not a contact adhesive. Just enough to speard the glue evenly.
Apply fresh urathane glue to unstretched bladder and use a vastly oversize patch. Roll on the patch. When dry trim leaving a 1 inch overhang, Unlike TPU the patch can be rubbed down. If you have spare glue, an artist paintbrush can be used to paint on a thin second layer of glue around the join after say 9 hours or so, while still tacky. It wont be 'working time dependant'. Some glues skin very quickly. A 10 inch blowout might require 30 inches of glue.
2 TPU patch - domestic iron and oval cable
This requires addition bladder material (not too old) and oval PVC mains cable maybe 6 or 7 inches long as the internal support (bendable) and a standard iron. Four weld sections might do the trick with weld width around 6/7 mm. A domestic iron is not ideal so requires a few dry runs. Cable entry/exit hole can be easily repaired with Tear Aid. The cable can also be inserted/removed by passing through the bladder end, Its an easy repair for a bag sealer. Paper can be used as the iron MUST not touch the bladder directly.
3 Heat seal - Additional seam
This method requires a standard bag heat sealer with 5 mm (not 2 mm) wide element. Mark out first on unstretched blader. Close the with hole pegs. Two welds should suffice with both crossing round the centre of the repair. Requires experimentation with some spare bladder material and sealer timer.
The bladder may stretch slightly when fitted but shouldnt cause a problem. If the joint is overheated and blows through treat the hole with Tear Aid or a small piece of TPU. As always test by dunking in water AND applying a little pressure. Alternatively, the iron and oval cable approach can be used .
4 Tear Aid (Type A patch)
Local repair guy method. Requires a lot of skill and assistance. If it goes wrong its a long way back. Requires a hair dryer to finish and preperation with strips of sellotape to give the bladder a structure and to isolate the inside of the bladder from the Tear Aid. Mark out bladder and trim away stretched bladder before rolling on tear aid. If the bladder is taut in wont crease. Use AC room if you have one.
5 Internal and external patch
Why an internal patch? It gives the bladder back its structure and effectively thickens the bladder wall in preparation for Tear Aid application which reduces risk of creasing, so:
a Trim stretched bladder and make a small slit on underside of bladder say 3 inches
b Pull some of the bladder inside out. Align and seal the hole using a not too sicky general purpose tape. NO creases. Put bladder back to normal
c Holding bladder taut carefully roll on Tear Aid after first having first marked out the bladder. Internal tape can then removed (optional)
d Repair slit with Tear Aid
It is not possible to rub down TPU its too thin and slippery. Its an internet myth
Be careful with cleaning materials. I use pressure hose (water), washing up liquid or swab. Better to use nothing than leave a deposit. Never use anything coloured.
Im not a massive fan of talc powder other than for talcing a repair that is still tacky prior to pulling in the bladder
If leading edge has very slowly leaking best thing to overpump the kite and listen or and spray with soapywater.
All LE bladder blowouts seem to require complete removal of bladder. Excess bladder material can be stored in a plastic bags. While the bladder is out it would be a simple matter to put a ring of glue around each 'valve'
A controlled area is required as the bladder is fragile. I use the spare bedroom.
Best glues...seam grip (my go to, very thin) aquasure, aquaseal, stormsure, plastic acrylic adhesive (sets quick)..dont use glue that has thickened
Tear aid can be removed with acetone and a cotton bud. Takes a while
its impossible to quantify glue setting time as it depends on temp and humidity
Photos or it never happened ??
The words Blow and Thai made me look at this post