What are optimum parts for QEV's?

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.
warhead052
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Tue Mar 22, 2011 3:00 pm

I would like to know what would be the best to use, pvc, brass, or steel? I would also like to know if I could get some easy to make schematics rather than a video. Thanks.
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Labtecpower
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Tue Mar 22, 2011 3:11 pm

BRASS!! Steel rusts easily, and I just don't like PVC.
warhead052
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Tue Mar 22, 2011 3:17 pm

Brass it is then. I will try and get the parts either saturday or sunday and get started.
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saefroch
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Tue Mar 22, 2011 3:34 pm

I recommend against brass, referencing this incident. I highly recommend stainless steel, because of the high strength and resistance to corrosion.
warhead052
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Tue Mar 22, 2011 3:37 pm

Wow, 1,000 psi? Thats a bit much wouldent you say? I will start out with pvc and a sprinkler valve I guess, and then work my way into metal.
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saefroch
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Tue Mar 22, 2011 3:39 pm

Except the 1,000psi has nothing to do with the failure in question. That was caused only by the stress from tightening and loosening the fitting.
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Labtecpower
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Tue Mar 22, 2011 3:40 pm

Stainless steel is beautiful, but very hard to work with (hard to weld and solder)

Brass is good enough for the average gun.

If you want schematics, just browse the forums. There are plenty of examples. (I found them too a year ago :roll: )
warhead052
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Tue Mar 22, 2011 3:47 pm

Ok. I really need to decide whether I should use steel or pvc. I am thinking pvc because its a bit easyier to work with, but steel has more fitting options, plus you can unscrew barrels :P If you have any suggestions on what to use as a first time let me know.
warhead052
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Tue Mar 22, 2011 3:55 pm

I just got an idea, tell me your thoughts. There's a local gun store close to my house, and they have wooden scraps of old rifles, should I get one of those, hollow out the stock for a air tank, and add in my own barrel and trigger? Would that even work?
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Zeus
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Tue Mar 22, 2011 5:47 pm

It certainly would work, Jook13 (I think) made a very nice coax around a home made stock, if you have access to such stocks I would recommend using them.

Hollowing out the stock has a major problem, the strenght of pressure vessels is strongly related to the geometry of said vessel.

A coaxial launcher isn't too hard to build, if you're considering home made piston valves a coax is somewhat easier.
/sarcasm, /hyperbole
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clemsonguy1125
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Tue Mar 22, 2011 6:10 pm

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Zeus
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Tue Mar 22, 2011 6:44 pm

Thanks, my searches seem to work as well as my brain at the moment.
/sarcasm, /hyperbole
warhead052
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Tue Mar 22, 2011 7:22 pm

Nice, thanks guys.
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Gun Freak
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Tue Mar 22, 2011 8:01 pm

You can have a screwable barrel with pvc you know... pvc fittings can have threads...
I reccomend PVC. It is the cheapest and also easy to work with and it can hold pressure well.

Wait I just realized you are using a QEV lol :lol:
In that case, get you some galvanized nipples and fittings and crank it up!
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warhead052
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Tue Mar 22, 2011 8:14 pm

Ok thanks. I am open to all sorts of ideas and suggestions, and when I get some spare time and money I will definitely get to work. If anyone can, will you link me to a coaxial tutorial? Or is that simply a QEV? (I am pretty new to pneumatic guns.... I have made only 1 valveless gun, and its pretty nice, shoots off 20oz diet coke bottles, and 2 liters...)
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