new project and need advice on power

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
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mattyzip77
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Thu May 03, 2012 6:29 pm

A QEV pretty much is a piston valve in itself. They are 100 times more powerful than a sprinkler valve in my opinion and you can get them really cheap. Check on e bay under qev, diaphragm valves, dust collector valves, etc. Good luck!!
Go Bruins!!!!
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jackssmirkingrevenge
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Thu May 03, 2012 11:44 pm

beastmode986 wrote:what ammo do you reccomend? i dont know where to get an rifled barrel
I would go for a 1/4" barrel and medium weight 0.25" pellets like for example these: http://www.pyramydair.com/s/p/H_N_Spitz ... _200ct/736

Important that they are "diablo" shaped and around 20-25 grains.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Fexo180
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Fri May 04, 2012 3:04 am

i have 4 qev devices up and running.. of which are 3/4 thread barrel type qev.
the first uses 1.5kg al. fire extinguisher as the chamber. ghetto fixed to a 3/4 elbow then into qev.. 17mm id 2mm walls 'gal-tube' barrel 900mm long threaded end to suit 3/4 into qev exh..& no, it is not seamless < that'll get some lads cranking on me about safety..muuahaha.

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The 2 other 3/4 are built pretty much the same but using gal stand pipes for the chambers.. one is 1 inch od. 450mm long capped, elbowed to qev.. the other 1+3/4 inch od @ 300mm capped e.t.c into qev.
the barrels on these are stainless steel seamless tube 3 mm walls and inner diameter of 9.5mm. 6-700mm long. these were scavenged from an old meatworks i believe they were steam lines.. they had olives and fittings @ the joins to my luck they were 3/4 :)

These 3 devices use the same filling and triggering set-up.
brass T piece off the pilot side of qev. bottom leg goes into a reducer then fit a tyre chuck valve as a trigger. off the backside of T piece air tap, elbow, then fit male quick connect fitting. the elbow is so the filling valve is turned down and dosn't rest on your cheek.. a damned good idea if the air tap fails... face shredder.

So the system is.. load projectile, connect air hose, open tap to fill chamber, shut tap off, disconnect hose, locate target and fire by depressing the trye chuck valve.
I played around with the T pieces by choking them with short lengths of hose that fitted inside to drop the pilot volume. that lightened the trigger nicely.

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The 4th is a Frankenstein concoction using a festo 3 port valve with a 1/4 qev, small chamber, brake line barrel for a simplistic semi auto. however i dropped this project due to being to bear club handed for the fiddly chit, it works but have not made a loading mech for it.

Note..I can only push 145psi in my old compressor and even then they are all loud.
3/4 will generally out do the 1/4 in most spudding applications.
beastmode986
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Fri May 04, 2012 3:21 pm

ok thanks alot! would it be possible for me to just make a 3/4in qev or 1/4 in qev?
also .25 seem a bit small for my desires however can it shoot through 1/4 in plywood? and would it be easier to find a barrel? If yes id rather use .25s than anything else
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Fri May 04, 2012 3:24 pm

beastmode986 wrote:also .25 seem a bit small for my desires however can it shoot through 1/4 in plywood?
With this setup at just 100 psi I can shoot through 1/4" plywood with an airsoft BB...

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Up that to 300 psi with a longer barrel and with pellets you will have no shortage of power.
hectmarr wrote:You have to make many weapons, because this field is long and short life
beastmode986
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Fri May 04, 2012 5:40 pm

hmm ill be extremely satified if i can shoot through 1/2 in pine i heard that takes some force you think i would be able to shoot through that?
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Fri May 04, 2012 5:56 pm

beastmode986 wrote:hmm ill be extremely satified if i can shoot through 1/2 in pine i heard that takes some force you think i would be able to shoot through that?
With a three foot barrel. 1.5 cubic inch chamber and 400 psi, you will make it through 1/2" of pine extremely comfortably.

spoonfeeding stops here, just friggin make it :D
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hectmarr wrote:You have to make many weapons, because this field is long and short life
beastmode986
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Fri May 04, 2012 6:01 pm

ok thanks! lol before i get a qev should i buy one or make one? i was theinking about making a 1/4in qev and ill be using a 6in chamber and where can i find a barrel
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Fri May 04, 2012 6:15 pm

Seriously, last answer.
beastmode986 wrote:ok thanks! lol before i get a qev should i buy one or make one?
http://www.spudfiles.com/forums/semi-au ... 23626.html

save yourself the heartache of making one
i was theinking about making a 1/4in qev and ill be using a 6in chamber and where can i find a barrel
http://www.ebay.com/itm/3-8-OD-X-049W-1 ... 22f96e4dbc
hectmarr wrote:You have to make many weapons, because this field is long and short life
beastmode986
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Sat May 05, 2012 12:38 pm

ok this is going to be finished by next weekend :D but last time i asked everyone if i should get a plastic qev they said it might bursat at 400 psi? im probably going to buy a metal one thanks for the help
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Sat May 05, 2012 11:03 pm

A plastic QEV :? wait, what?
hectmarr wrote:You have to make many weapons, because this field is long and short life
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Fexo180
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Sun May 06, 2012 3:26 am

i'm kinda pissed that no-one commented on my lovely lino floor :( LOL
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Sun May 06, 2012 3:28 am

Fexo180 wrote:i'm kinda pissed that no-one commented on my lovely lino floor :( LOL
Truly fapworthy, congratulations :) but if you want more enthusiastic feedback, break things and film it, that's the general rule on this forum :D
hectmarr wrote:You have to make many weapons, because this field is long and short life
beastmode986
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Sun May 06, 2012 7:37 pm

ok i went to lowes today and bought everything besides a barrel and qev those will be ordered shortly but by plastic qev i thought that the qev in the semi auto valve post was plastic i also thought it cant hold 400 psi?

EDIT: will this work? because im going to buy it tommorow if i can use it
http://www.ebay.com/itm/Pneumatic-1-4PT ... 3f16a93fb8
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Mon May 07, 2012 12:30 am

beastmode986 wrote:will this work? because im going to buy it tommorow if i can use it
Yes, but check the threads! That's the only issue with these cheap QEVs, they're advertised horribly.

The ones I mentioned in the semi auto tutorial are BSP.
i thought that the qev in the semi auto valve post was plastic i also thought it cant hold 400 psi?


No, it's painted metal.
hectmarr wrote:You have to make many weapons, because this field is long and short life
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