SpudFiles

I just finished this QEV gun today, and it is really impressive, even more impressive than my first piston valve.

SPECS
valve: 3/4 in QEV from Fastenal
pilot valve: 3/8in ball valve
barrel: 4 ft of 1/2 in copper
chamber: 3 ft of 3/4 in copper
pressure: 100-150 psi

This gun vaporizes potatoes when shot, so marbles are the best ammo.

This was a pretty fun one to build, and it was my first time soldering pipe.

I like, a lot!Nice damage to those cans.

You could shorten the tube going from the blowgun to the valve and get a performance increase.How much was that 3/4 QEV?

rna_duelers wrote:You could shorten the tube going from the blowgun to the valve and get a performance increase.

Or mound the blowgun directly to the QEV and add a trigger on a rod extension.

Nice cannon, i've always wanted to use copper. Looks like your soldering turned out good as well, nice job.

@JSR and RNA

The pilot volume is reasonably small, the I.D of the pressure hose is only about 5mm, and that 1/4" galv tee is nothing big either. Though he could upgrade the blowgun for better performance.

His blowgun has a piece of like blue hard foam between the level and the push rod which will make it open more fully, and if you used a 1/4" ball valve for piloting you could take it up to 150psi, the pressure limit for qevs. It would be a bit unwieldy but it would pilot faster and again you could crank the pressure.

Thanks for the comments.

Has anyone who has used a QEV noticed that when it is opened it makes a ping, similar to the ejection of a clip in an M1 Garand?

Would anyone mind running this gun through GGDT, as it doesn't work on my computer?


I just changed the blowgun to a 3/8in ball valve, and the power increase is crazy. With the ball valve piloting the QEV, I put a nail through a coin.

Nice cannon. I like the can damage. Glad to see someone else uses the Fastenal QEVs too 8).

Thanks, Fastenal was the only place I could find QEVs, so I really had no choice, but they do a good job. I ordered my valve and got it a day and a half later, without paying any extra shipping.

Sweet, so thats great the ball valve helped that much. Did you increase the pressure to 150psi?

is there anywhere you can get QEV's in new zealand? can't seem to find them anywhere. nice gun btw

its a cool looking gun, but my recommendation is that you turn the ball valve 90 degrees, that way its like a trigger.

my QEV gun also uses a ball valve for exhaust and trust me, its more comfortable if you turn it 90 degrees. just put a 45 on the nipple and it will do you wonders.

battlemonkey wrote:is there anywhere you can get QEV's in new zealand? can't seem to find them anywhere. nice gun btw

Yeah there is, just the one place I know of, they cost a fair penny though.
<A HREF="http://www.rsnewzealand.com/cgi-bin/bv/ ... =nzie">3/4" QEV</a>

If the link doesn't work, go to http://www.rsnewzealand.com and search Pneumatic P4Q quick exhaust valve,G3/4 then look at the first 4 results.

Someone did get one from a hydraulics store, but stock would vary between stores.

I can get them from a number of places,hydraulic places included although they aren't cheap,if they were I'd be using one.

@spudgunner

yeah, the blowgun couldn't open the QEV fast enough, so the valve was honking. I haven't taken it to 150psi, but I will today.

@hi

I will probably turn the ball valve around today, does it really make that big of a difference?

You could mod your blowgun and use that instead of a ball valve.