i have been checking out this site for a while now but never posted. a couple of weeks ago i was inspired to make a pneumatic cannon, so i did. once i was satisfied with it (that took a while) i got up the motivation to fire it. hooked it up to a small portable air pump and got the chamber filled and took it outside and let it rip. a couple things: 1) it was at night so i couldnt quite see how far it went but the flight time was atleast 8 seconds (i fired it over water so i listened for the splash) and 2) the compressor could only get the tank up to 50 PSI. what i am wondering is this, the Rainbird valves, does anyone know if it is safe to take it up to around 120 PSI? .... the way i figure it is the blowgun valve i have is rated for 90 PSI and since the sprinkler valve is modded and all the hoses are rated for more than 120 PSI, so my only concern is the max PSI the Rainbird can handle. anyone know?
P.S. tomorrow i will take some pics and post them although damage shots may be a bit tough since i live in an area that doesnt exactly lend itself to privacy, but i shall try!
the first firing...
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jackssmirkingrevenge
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The small portable air compressors aren't really worthwhile, get yourself a bike pump - fills quicker to a higher pressure and you get some exercise too 
120 psi should be ok for the rainbird.
120 psi should be ok for the rainbird.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Pete Zaria
- Corporal 5
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Welcome to SpudFiles.
As Jack pointed out, those portable compressors aren't very powerful or reliable - they're really only made for getting car tires upto 35-40 psi tops. A good bike pump is better, and of course, a "real" compressor is best.
Those rainbird valves, I think, are rated for 125psi or so, and will work fine upto that pressure (even a bit beyond but we don't recommend it). The question is your pipe and fittings.
Did you use NSF-PW pipe? Schedule (Sch40, Sch80, etc...) is just a wall thickness rating and is NOT a pressure rating - the pipe needs to say "NSF-PW" and "xxx PSI" or "xxx BAR" to be pressure rated. The fittings should also be pressure rated and should not have shallow sockets. If your pipe and fittings are pressure rated, you're safe upto at least 120psi. If they're DWV (as many people use for their first guns, without knowing better) you shouldn't go over 60-70 psi. DWV pipe (made for Drain Waste Vent) is very commonly found at hardware stores - in fact, that's what 95% of hardware stores around here carry - and it's not pressure rated and not safe for higher pressures. It's OK for combustion guns, though.
Looking forward to pics and a more detailed description of your gun. Hope you stick around our forums.
Peace,
Pete Zaria.
As Jack pointed out, those portable compressors aren't very powerful or reliable - they're really only made for getting car tires upto 35-40 psi tops. A good bike pump is better, and of course, a "real" compressor is best.
Those rainbird valves, I think, are rated for 125psi or so, and will work fine upto that pressure (even a bit beyond but we don't recommend it). The question is your pipe and fittings.
Did you use NSF-PW pipe? Schedule (Sch40, Sch80, etc...) is just a wall thickness rating and is NOT a pressure rating - the pipe needs to say "NSF-PW" and "xxx PSI" or "xxx BAR" to be pressure rated. The fittings should also be pressure rated and should not have shallow sockets. If your pipe and fittings are pressure rated, you're safe upto at least 120psi. If they're DWV (as many people use for their first guns, without knowing better) you shouldn't go over 60-70 psi. DWV pipe (made for Drain Waste Vent) is very commonly found at hardware stores - in fact, that's what 95% of hardware stores around here carry - and it's not pressure rated and not safe for higher pressures. It's OK for combustion guns, though.
Looking forward to pics and a more detailed description of your gun. Hope you stick around our forums.
Peace,
Pete Zaria.
yeah the pipe i used it preassure rated, 3/4" thick wall, i think its like 280 PSI or more. as for the bicycle pump, do you mean one of those pumps that sits on the ground and you pump with your foot? ... wouldnt the pressure be too much for it after a couple of pumps?
P.S. after a few more days in my shop i seem to have a total of 4 pneumatic cannons and so i think i will be investing in a compressor or building some sort of rig to impliment a paintball CO2 tank for total automony.
P.S. after a few more days in my shop i seem to have a total of 4 pneumatic cannons and so i think i will be investing in a compressor or building some sort of rig to impliment a paintball CO2 tank for total automony.
Awesome. The compressor is the best way to go. Seeing as how you've taken to pneumatics (always good 
) you should invest.
As far as CO2 goes, checkout my CO2 faq. It should answer any questions you have. If it doesn't you could shoot me a PM or just post on that thread. It will get answered (if I don't know, I will find out).
Also be warned, using CO2 in a cannon will probably not be as efficient as you would like if you have a fairly large chamber. Like I said, just check out the thread and you will understand.
) you should invest.As far as CO2 goes, checkout my CO2 faq. It should answer any questions you have. If it doesn't you could shoot me a PM or just post on that thread. It will get answered (if I don't know, I will find out).
Also be warned, using CO2 in a cannon will probably not be as efficient as you would like if you have a fairly large chamber. Like I said, just check out the thread and you will understand.
if you want good bicycle pump get "floor pump" ,if you don't know what floor pump is ... use googlekaiser271 wrote:yeah the pipe i used it preassure rated, 3/4" thick wall, i think its like 280 PSI or more. as for the bicycle pump, do you mean one of those pumps that sits on the ground and you pump with your foot? ... wouldnt the pressure be too much for it after a couple of pumps?
compressor is best way to go ,but i use quite much those floor pumps too.