[Martijn]

I built a t-shirt cannon this fall, and we used it for some robotics promotional stuff. Took it to a basketball pep-rally, that sorta thing.. Although PVC might not be the safest thing, you're probably ok as long you make sure that not only the pipe itself, but also the fittings are all pressure rated. The only thing that isnt pressure rated in my setup was the sprinkler valve. We've managed to hook it up to 4 compressors, and load the reservoir all the way up to around 140PSI, and we can shoot t-shirts across our school's gymnasium (two basketball courts side by side).
We had also planned to hook it up to a promo robot (similar to 1726), but we ran out of time in the fall.. Maybe the team will hook the cannon up to a kit chassis with a mechanum drive or something this fall..