SpudFiles

Is a McMaster (american) QEV safe to use at repeated rapid de and re pressurization of the chamber to 300 psi?

Also, is it safe to use CO2 with this valve?

Thanks.

yepp it is 100% safe with 300psi of whatever (not oxygen etc)

Thanks man.

Well i really wouldnt say its 100% safe because those are meant for like 125 psi max, but people have taken them to 800 psi without failure, so i think 300 psi wouldnt blow it up.

I have seen 3/4" taken to higher pressures.
I think that a 1/4" would work fine, the only thing that would fail would be the diaphragm/piston

sweet. i have one coming in the mail that im gonna take to 600....

VH_man wrote:sweet. i have one coming in the mail that im gonna take to 600....

Nice, what do you plan on shooting out of this?

with 6 feet of .18" ID aluminum tubing coming as well, ill let you guess

If you were wonderin' whats coming outa my barrel (hehe) think 6mm and full auto.

whoooo........... i guess two of us are thinking the same thing but in different calibers.........

(e-high-five)

mine will be more of a High-velocity test bed at first though..... GGDT extimates 1400 FPS at 500 PSI if i make my chamber big enough..... something i really cant argue with.

Yeah, but is that with the 72 inch barrel? I'm aiming to make mine ultra portable.

Edit: GGDT says 842 fps at 300 psi

I might have to get a 40 psi safety pop off valve for use with my friends/living objects

im aiming to put a .177 BB through 1/2 plywood.... lol.

that and to break the sound barrier. i might cut it down though..... it is a wee bit long.

nothing is too long VH

well serious then, a 6 foot cannon isn't that long really, the problem is that you cant get to 1400fps since that is near the particle speed of air. plus that the sound barrier will hunt you down.

cut of the barrel small lengthes until it starts loosing a tiny bit of speed and then you have your perfect length of the barrel.

i am a confusing guy

Al-xg managed to rupture his (UK-type) QEV piston diaphragm while it was being used at 850psi (regulated from a 3000psi HPA paintball tank) by pushing the barrel too far into the valve so it poked the flexible piston.

I personally think 850 is OTT despite it working for him for over 100 shots the diaphragms are not indestructible and I'd hate to have one burst (literally becoming a randomly triggered burst disk) on me.


If you really want to have some confidence in what you feel is safe to use a valve to you need to ask the manufacturer what kind of safety factor they used.

300 PSI shot with Q.E.V.

I'd say they're safe... just don't load until you're ready to shoot, and definitely watch the muzzle. If anything, you'll get a failure of the seal, which would cause whatever's in the barrel to be launched.