SpudFiles

So I've been browsing the forums looking at all the piston guns and I'm noticing bulky ball valves or sprinkler valves as piston acuators. I don't have any experience with push button valves, but I was curious if ,on a small 2" Tee, you could use a push button valve to acuate the piston.

If by push button valve, you mean blow gun, then yes, you can.

http://www.spudfiles.com/forums/my-firs ... 12796.html

assuming your pilot volume was kept at a minimum and your piston was a very tight fit, it's possible to actuate it with a schrader valve, it's all a matter of the tolerances you can build to.

Chances are you wont be able to have such good tolerances and you wont use o-rings, so if you used a blow gun, you could lose up to 30% in performance compared to a 3/4" ball valve or 3/4" or 1" sprinkler valve.

I'd sacrifice 5% per formance for good looks and comfort, but not anything higher.

This is my 2" piston cannon, I used a 1" sprinkler valve:
http://www.spudfiles.com/forums/viewtop ... tml#100616

Here's what to do.

Get your pushbutton valve, it'll probably be a three-way, (that's the cheapest kind I can find, usually), so you can both fill your launcher and fire the launcher with the same valve, without disconnecting the air source.

Now, get a 1/4" Q.E.V. Many people will tell you to go bigger, but if your piston is a reasonably tight fit, and your pilot volume is feasible, then you will have no problems. Hook the CYL end to the pilot, and hook the three-way exhaust/fill assembly to the IN side.

With the right "cascade assembly", you can trigger a monster 6" piston valve with a pin-hole covered with your thumb. It just depends on how many valves you have between the pinhole and the pilot.

Thanks for the input. I was just looking to build a clean looking pneumatic. Performance isn't really a high priority atm. Just a simple/clean piston.
6790T42 is the MC master part number for the push button valve, but it looks nothing like the push button modded sprinkler valve joel has on one of his guns. The Screenshot escapes me atm. I guess what your saying is in order to fill my gun i'll send the air through the push button valve? While also using the same valve as the vent. Thanks again for the help.

Edit to add link of Push button: http://www.spudtech.com/detail.asp?id=52

I believe <a href="http://www.mcmaster.com/nav/enter.asp?p ... 5K11">this valve</a> is what Joel uses. You don't have to fill through that valve if you don't mind shutting off the input flow before firing, but you can fill through the valve if you want. I would expect that you would need o-rings and a check valve in your piston to be able to use a valve that small to pilot.

sorry to interupt with stupid question...
how much longer does it take to fire the gun when you have na additional piloting QEV in comparison with direct piloting of the firing valve?

is it just opening time of the piloting valve + openieng time of the piloting qev + opening time of the piston valve or does it take longer ?