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Pressure Rated Pipe
Posted: Tue Nov 18, 2008 4:53 pm
by theepicmool
Is it safe to use pipe that isn't pressure rated but that is sch40? If so does PVC/ABS make a difference? I just think it will be difficult to find pressure rated pipe at any store near me.
Posted: Tue Nov 18, 2008 5:39 pm
by jonnyboy
ONLY USE NSF PW PIPE!
abs tears as opposed to explode like pvc does.
Posted: Tue Nov 18, 2008 6:01 pm
by theepicmool
NSF PW? What if it just has a PSI rating or just has NSF PW stamped on it.
Posted: Tue Nov 18, 2008 6:09 pm
by MrCrowley
theepicmool wrote:NSF PW? What if it just has a PSI rating or just has NSF PW stamped on it.
That's fine. As long as it has a PSI rating or NSF-PW on it, it should be fine for pressure, read this:
http://www.spudfiles.com/spud_wiki/inde ... _Rated_PVC
Posted: Tue Nov 18, 2008 6:36 pm
by theepicmool
ok, but how much pressure can NSF PW guarantee?
Posted: Tue Nov 18, 2008 6:40 pm
by MrCrowley
Depends on the diameter and SCH rating.
This should help you:
http://www.pvcplus.com/PVC%20schedule_40_&_80_pipe.htm
Though most people rarely go above 180PSI with PVC, even if the rating is a few hundred PSI. If you're going over 200PSI, i'd recommend metal components.
Posted: Tue Nov 18, 2008 7:01 pm
by theepicmool
One last thing: Why are PVC cannons more popular then ABS ones when ABS just tear and don't explode? If both are pressure rated is there really any distinction? can i put ABS fittings on PVC pipe and vice versa?
Posted: Tue Nov 18, 2008 7:08 pm
by MrCrowley
Because pressure rated ABS is harder to find and more expensive I think. If pressure rated ABS was just as available as PVC, it'd be a far better material to use.
It's true, ABS will just tear, but since it's easier to find pressure rated PVC then pressure rated ABS, people go with PVC. The ABS that you will see on cannons is most likely DWV (not rated).
Yes you can put ABS fittings on PVC with a special glue. I wouldn't recommend it for pneumatics though.
Posted: Tue Nov 18, 2008 7:55 pm
by starman
Also, if you use pressure rated PVC pipe and parts, do a thorough and proper construction job and keep pressures down under the ratings, you have an extremely low chance of a PVC explosion.
Posted: Tue Nov 18, 2008 8:27 pm
by theepicmool
What about wrapping in duct tape/drywall tape? I've seen it on some others and it seems that it would keep the shrapnel together in the event of an explosion.
Posted: Tue Nov 18, 2008 8:34 pm
by MrCrowley
theepicmool wrote:What about wrapping in duct tape/drywall tape? I've seen it on some others and it seems that it would keep the shrapnel together in the event of an explosion.
Tape wont do crap. A leg from a pair of jeans probably is the best to contain shrapnel, but it's pointless if you make your cannon correctly with pressure rated fittings.