knotwindy wrote: ↑
Fri Nov 20, 2020 3:53 pm
Are you saying they are doing it fast and cheap instead of right because it is such a small market? Or is it just the ‘nature of the beast’ that they can’t figure it out with too many variables?
Just explaining the method used by most factories. Nothing fast and cheap on this method btw, I ran a kite factory and its not so simple as people may think. Something may look perfectly welded in the factory but may contain a weakspot that only starts to leak after some use. No kite leaves a factory without a pressure test. The PU bladder is very thin, the PVC valve (relatively) thick, we now added extra layers because of the twisting inflate/deflate... too much heat and the thin bladder melts too much, not enough and the PVC and glue foil did not heat enough. So yes it is a very complex part and can go wrong because of many factors.
But to be honest.....to my knowledge old kites also delaminated.
When something goes wrong you may see that in an entire batch of brands a+b+c the valves delaminate as they are made in the same factory by the same machines same valves and same foil batch etc.
As for the question in the starting post. You cant weld pvc to PU directkly and I even doubt you can welt a thin PU foil directly to a thick PU valve. The heat from the top part has to transfer through a thicker surface then on the bottom....its not that simple but for sure if the industry was 100 times larger .... Also QC and QA of all different parts and machines cant be the same level as in the airplane industry or the kite would have to cost the 10 fold.