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Blowgun PSI rating

Posted: Mon Feb 23, 2009 4:53 pm
by Team PSU
Hi guys,
I will be adding a blowgun to our sprinkler valve. On the side of the blowgun available it says Safety Blow Gun - 30psi max. The ones available from BCARMS are 120psi blowguns. Is there a significant difference between these two blowguns?
Please advise,
Thank you
TEAM PSU

Posted: Mon Feb 23, 2009 5:00 pm
by jrrdw
90psi. The 120 psi rated blow guns will normaly hold more. I myself have seen them hold 160psi for years, off and on as needed in auto repair shop.

Posted: Mon Feb 23, 2009 5:04 pm
by SpudsMcGee
Well one is rated to 30psi and the other is rated to 120psi. But that won't matter if you are using it to mod a sprinkler, I think... The rating is for when you have it hooked it up to a compressor, that if the pressure is over 30psi (on the safety) it might leak, but like I said I don't think it shouldn't matter since it is hooked up to a sprinkler valve. But I'll admit I don't really know, for your sake and mine hopefully a veteran will tell more, because I'm just rambling on to try to make you think I know what I'm talking about.

Edit: Oops, a vet already answered, oh well...

Posted: Mon Feb 23, 2009 5:07 pm
by trigun
I have a 30 psi rated blow gun and have had it taken to 500 psi before with no leaks and I know of other members that have taken them farther.

Posted: Mon Feb 23, 2009 9:12 pm
by Leonard
Unfortunatly wrong, SpudsMcGee.

The blowgun, while attached to the sprinkler valve as a pilot, will be under the exact same pressure as in the air chamber, so a 30 psi rated blowgun would NOT be suitable for the type of pressure normally used in PVC spudguns (100-120 psi) even if used as a pilot for a sprinkler valve.

Posted: Mon Feb 23, 2009 10:25 pm
by Lego101
I remember hearing that the thirty psi blowguns are only rated as such because the nozzle may break if jammed with anything. Keep in mind, this is only what I've heard, so don't quote me on this.

Posted: Mon Feb 23, 2009 11:03 pm
by trigun
When you mod a sprinkler valve you remove the nozzle to increase flow.

Leonard, Yes they are suitable for a pilot valve to sprinkler valves. They CAN and do hold the pressure of most if not all pvc cannons.

Posted: Tue Feb 24, 2009 9:37 pm
by Team PSU
Ok. So I'm still in the air for this topic but am leaning on just using the 30psi blowgun. I will continue to check in while this topic is discussed.

Posted: Tue Feb 24, 2009 9:47 pm
by daberno123
What model/kind of blowgun is it? You've given the rating but who manufactured it and where did you get it from?

If it's the normal red handled Husky blowgun or the blue handled Kobalt one then you will be fine using using it with anything your normal shop compressor can output.

Posted: Wed Feb 25, 2009 3:17 pm
by psycix
I'm using one thats rated at 12 bar (bout 175 psi) on 30 bar (almost 450 psi)

Blowguns can handle WAY more then what they're rated for.
And even if you do happen to overload it, the first component to fail is probably by disaligning or rupturing an o-ring making it leak.
This can be repaired.

Posted: Wed Feb 25, 2009 3:35 pm
by john bunsenburner
a blow gun wont leak if the pressur eis to high, the most likely thing to happen would be the trigger begining to get very hard to push at high pressures.

Posted: Wed Feb 25, 2009 6:50 pm
by frankrede
john bunsenburner wrote:a blow gun wont leak if the pressur eis to high, the most likely thing to happen would be the trigger begining to get very hard to push at high pressures.
And you know this how? I have had many leak at anything over 250 PSI.

Posted: Wed Feb 25, 2009 8:43 pm
by POLAND_SPUD
@frank I think he meant that if you connect a blowgun in the right way it shouldn't leak... at least in theory becasue the higher the pressure the more force is keeping it shut

of course if it is connected the other way round it will leak as soon as the pressure acts with greater force than the spring that keeps it normally shut


stuff that's not rated to pressures you are using can always leak or fail...
however the fact that some useful stuff (blowguns, QEVs, malleable iron fittings) is often rated to pressures lower than it can safely handle just to lessen the chance of any law suit if someone gets hurt when using it (or abusing it) of course there are other things as well




who needs QEVs rated to 50 bar if roughly 99% of compressors are max 15 bar compressors and virtually everything for pneumatic systems (vavles, airhoses etc) is rated to 15 bar?

if you write that they are rated to 15 bar you can always claim that they are good up to several milion cycles (of course at 15 bar.... but again 99% of customers don't need more)

Posted: Wed Feb 25, 2009 9:41 pm
by frankrede
POLAND_SPUD wrote:@frank I think he meant that if you connect a blowgun in the right way it shouldn't leak... at least in theory becasue the higher the pressure the more force is keeping it shut

of course if it is connected the other way round it will leak as soon as the pressure acts with greater force than the spring that keeps it normally shut


stuff that's not rated to pressures you are using can always leak or fail...
however the fact that some useful stuff (blowguns, QEVs, malleable iron fittings) is often rated to pressures lower than it can safely handle just to lessen the chance of any law suit if someone gets hurt when using it (or abusing it) of course there are other things as well




who needs QEVs rated to 50 bar if roughly 99% of compressors are max 15 bar compressors and virtually everything for pneumatic systems (vavles, airhoses etc) is rated to 15 bar?

if you write that they are rated to 15 bar you can always claim that they are good up to several milion cycles (of course at 15 bar.... but again 99% of customers don't need more)
I have heard that too, but I have leaks, the blowgun is non-modified as well, perhaps my seal is dirty?

Posted: Wed Feb 25, 2009 9:50 pm
by jrrdw
Some parts are just machined poorly, thus creating a leaky blow gun. Just go with the highest rated available to you. :D