SpudFiles

It has been a long time since i last posted here and lately i've been looking at the HPA QEV guns and i'm wondering if they are safe? I would like to know if any QEV and blow-gun setup will handle HPA because i was looking into buying a pellet-gun/air shotgun but those are rare and i would much rather make one then buy one for $200+. i'd also like to know if its ok to use co2? CO2 is what i will be using along with a galv. steel chamber. i don't know if you have seen my last post but it was a post on my HPA BV shotgun but i never could find out how to make a spring loaded BV so i'm going to part it out and make a QEV gun. All i need now is a qev. If only i can find one... i'll probably buy one online...



thanks in advanced; sorry if i needed to research a 'lil more before i posted...

Are you planing to reg the hpa? because its like 4000ish psi unreged that would defiantly destroy any store bought qev.

A QEV and blowgun setup will happily take 500 psi or so, but CO₂ is pushing 900 psi for which a blowgun would not be suitable.

I wouldn't give up on the ball valve - if you use a detent seal, valve opening speed becomes irrelevant, so you don't need to spring-load it. Have a look at this, I was using the paintball tank valve itself and still performance was pretty spectacular.

i was actually going to use the 12g co2 things with a tire filler and fill the chamber with 400psi or so. will the blowgun handle it?

Marffy wrote:will the blowgun handle it?

Mine would go up to 500 psi before leaking.

what about the max psi on a QEV? most say max psi is 150? does the increased pressure make it a hard trigger pull?

Marffy wrote:what about the max psi on a QEV?

Some people here have used them to 600 psi

most say max psi is 150?

Who pays attention to ratings anyway

does the increased pressure make it a hard trigger pull?

In the case of most blowguns, yes

I have used my 3/4" QEV at 600 psi frequently and held up fine.

Remember smaller QEV, the more pressure it shall theoretically withstand.

Dave

Dave_424 wrote:I have used my 3/4" QEV at 600 psi frequently and held up fine.

Remember smaller QEV, the more pressure it shall theoretically withstand.

Dave

Thats true for the strength of the valve body, but usually the issue is diaphragms ripping. I've heard of people reinforcing them with nylon washers though.

Dave_424 wrote:I have used my 3/4" QEV at 600 psi frequently and held up fine.

Remember smaller QEV, the more pressure it shall theoretically withstand.

Dave

i too have used both my 3/4 and 1/2inch qevs up to the 650psi mark

but your statement about the smaller a qev the more pressure it can hold is not a very safe assumption. when they make the smaller QEVs they make them to meet the same regulations. its not like they build a 1/4inch qev out of the same thickness of materials as the 3/4. the smaller the qev, the thinner the walls becuase it doesnt have to be as thick to withstand the rated pressure and the safety factor

i'd think that all QEVs can handle the same pressure because of what c11man said and i agree.

If it does fail, chances are it will be the 'phragm anyway. You can also modify QEVs for more flow, like I did, by removing the 'support struts' which cover 1/3 of the 'EXH' and 'IN' ports.

I am aware of those things regarding the structure, however, from the QEV's that I use, the thicknesses are the same between the 1/2" and 3/4"

I am only going by my experiance

Dave

You can also modify QEVs for more flow, like I did, by removing the 'support struts' which cover 1/3 of the 'EXH' and 'IN' ports

better yet buy a 'european' QEV

Do European QEV's such as the fastenal one have no support struts? Can they handle the same pressure (600 PSI)?