[ZInventor]

the reason it fails is that PVC was never rated to go from 0-60 psi and back to 0 in less than a second.

the instantaneous stresses are just too much.

think of it this way, your tires give you traction at 60MPH, but if you try to go from 0-60 too fast, you'll spin out...

i know, it's totally different forces at work, but the result is essentially the same.

it's MUCH harder to create instantaneous pressure with liquids, as they do not compress, and once given more volume, return to 0 without much trouble.

i've seen first-hand the problems with PVC AND ABS!!! IMHO, don't use plastics of any kind for air pressure, unless they are flexible (ie. Pneumatics tubing)

just use metal.

Just my $0.02...

-Z