Thanks, DG. The valve needle wasn't going to be the actual trigger. I was going to cut down an eighth inch so the needle would be exposed to a sliding trigger yet to be made. Is exposing the needle like that a known problem-in-the-making?

Approximately 1/4 for the barrel diameter to achieve full flow, but typically one is advised to up that to 1/2-3/4 barrel diameter to avoid the piston bouncing back. I'm not getting this pictured in my head, JSR. In Clide's animation http://www.spudfiles.com/pneumatic-cannons/topic8157.html (BTW, i...

Thanks, guys. I was wondering about the volume on the backside, PeteS... the Schraeder valve will have the lip cut down to expose the pin for the trigger in the end, but does anyone else think that much volume will be an issue? Also, the little testing I've done so far, the piston is hard to seal wh...

Working on second gun, in the picture you can see the setup I'm attempting... I've watched wyz2285's YouTube video on the QEV/piston valve and Clide's helpful flash animation for the barrel seal. I want to make sure I have the concept down before moving on... I believe I have the tapered copper fitt...

Hey All, I have a question about making custom parts for my next gun. I don't have the tools to make beautifully machined aluminum, and was wondering if anyone has made molds and poured the Bondo fiberglass resin into it for parts? And by parts, not so much handle grips and exterior things, but cust...

Well, further analysis does indeed show my spring is not strong enough to pop that valve open as fast as it needs to at high psi. Thought I'd make a video for the fun of it.



Thanks for the comments. Time to upgrade.

Hi All, I built Gippeto's "stirrup hand-pump" and love it. I'm having an odd occurrence happen when I pump the copper pistol to 400+ psi range? I'll pull the trigger and there will be around a 250-400 millisecond delay, then the expulsion of air, but it's very weak :? It's like, What the heck happen...

machining is a beautiful vision. nice! Hope to see more.

Yes, thanks. Do I just put a thin layer on the piston then, or more places than that?

JSR, I see a 'broken' image link as a reply. Is that issue my end or spud's?

Ok, things are coming together nicely on the stirrup pump. Question: How do I lubricate the piston/tube and with what kind of oil?

Looking at this part of the check valve... The smooth part of the modified 3/8 bolt... when the cracking pressure is reached to push this down and compress the spring, is there any filing needed of the smooth walls on bolt to allow air to travel into manifold?

Come and see the pressure inherent in the check valve system! Help, help, I'm being compressed!

Thanks for the suggestion, JSR. I may go that route. Question about the DIY check valve in the stirrup... Do you think it can handle 500 psi?

Hey Guys,

In the stirrup pump pic... what is the hose attaching setup there? I'm trying to figure out what kind of hose to buy for the pressure and how to attach it to the piping.

Thanks!