SpudFiles

I just built my first pneumatic cannon and want to be as safe as possible with it because im doing this just to have good ol' backyard fun with the kids and don't want anyone to get hurt.

The reservoir is constructed of a 24" x 3" PVC pressure rated at like 240. The cap on the back side is also SCH. The reducer and bushing that im using to go from 3" down to 1" is DWV i believe but is thicker than the PVC. and im using a 1" ball valve leading up to my barrel. I've been using a 1" barrel and shooting normal sized superballs out. I'll post some pics on later.

I've only had it up to 50psi so far and get nervous filling it more and i wondered how high i can feel comfortable with swaying toward the cautious side?

Just because a part says "SCH40 or SCH80" doesn't mean it's pressure rated, that's just the thickness of the pipe. The pressure rating is either NSF-PW (good) or NSF-DWV (bad). I'd worry more about the back cap than the reducer.

I've taken DVW parts to 100PSI (remotely) quite a few times without issues, so I'd say 75-80 should be pretty safe to hold. However, I claim no responsibility whatsoever if you injure yourself.

BTW, consider upgrading the ball valve to a modified sprinkler - much more powerful.

Peace,
Pete Zaria.

OK... heres an update. all of my parts have NSF-PW on them including the back cap with the exception of the 3" to 2" which is partially over the 3" pipe. Any other safe recommendations for a PSI rating i can be comfortable with? I still have not had it up past 45-50ish.

just don't go over 40-50 psi if that is all you feel comfortable with.

yeah i wouldnt feel safe at 80psi with kids so stay under 70psi and youll be fine

The reason "reducing couplings", (the DWV kind), aren't pressure rated is that they have a long, unsupported angle where the 3" socket reduces to the 2" socket. Pressure rated reducing couplings, (yes, they do have them!), have a plastic webbing embedded in the walls and a stubby angle to get around this risk, and provide smooth flow inside a system.