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Posted: Sun Sep 06, 2009 2:01 pm
by twizi
a 1/2 qev could go to 900psi i would not risk it but it should technicly.
if i were to use a 1000psi i would use techs qdv in a stanless steel body but hey it your plans for your gun so it up to u.
Posted: Sun Sep 06, 2009 4:37 pm
by Gippeto
[quote="inonickname"]Jor, it was "go past 9000 and it will probably explode". The intended operating pressure was around 3000, for a safety factor of 3.quote]
Not quite. Close though.
The burst pressure was calculated using yield strength of the material and de-rated by 7/8 as per an astme formula that I had found at the time. This resulted in the ~9000psi figure. Using tensile strength, the results are considerably higher.
Hydro testing was done to 6000psi, with measurements (diameter) taken before and after for comparison. (No permanent change confirms that I'm below the yield strength of the materials at that pressure...at least as I understand things.
wngovr, in your shoes, I would look at using a spool valve to re-charge the chamber of a piston or qdv valve. The qdv does offer the simplicity of not having to also build a high pressure piloting valve (hammer valve in my case).
Lower required hammer forces (which DO impact trigger weights and add various recoil elements to the "launcher") are an added bonus.
Posted: Sun Sep 06, 2009 6:31 pm
by Mr.Sandman
wngovr wrote:Brian the brain,
Now..as tempting as a 3000 psi gun seems...What would you need it for?
Thats a funny question. does anyone
need a spudgun? Its all about power and damage, right? I shot the XM2 at 300 psi many times, then I went up to 400 psi. I noticed a definite improvement. Now I want MORE! The XM2 cant handle much more pressure, so if im going to build another launcher, I figured Id build one that can handle allot. Then I could find a happy spot for the pressure depending on the ammo I use. (40 cal.) My goal is 1000 F.P.S. or more.
Then again maybe thats not it. Maybe its the challenge of making a quality launcher that can handle those pressures.
B.T.W. Nice launcher. (Red Bull)
Hotwired,
Ill check into hammer valves, thanks.
Hmm to get extra funds you could send me xm2 so it wont distract your build

Setiously though why not just beef up xm2 instead of a whole new launcher?
Posted: Sun Sep 06, 2009 10:25 pm
by wngovr
Gippeto,
Im thinking about doing a cross between a barrel piston and a q.d.v. valve.
Setiously though why not just beef up xm2 instead of a whole new launcher?
The XM2 is what it is, and I like it that way. Besides 2 launchers are better than 1. Actually it will be my third.