First Piston Valve Pneumatic

[Gun Freak]

Hey guys, this is my fist piston valve attempt, and after about 20 different designs (lol), i came up with this.



i wanted to know if this would be an effective and powerful design. i shoot my current gun at about 120 psi[/img]

[deathbyDWV]

Looks like you've got it.

It should work.

What size of barrel will you use?

[Gun Freak]

i will be using a 1/2" barrel, that extends into the 3/4" T so that the piston can seal it.

thanks so much for the reply

[MrCrowley]

Your pilot volume looks a bit big, it's even worse that it is using PVC fittings as they seem to have more volume than same sized metal fittings.
Just try to keep it as small as you can, and if you can't make it any smaller, up the pilot valve.

[Gun Freak]

it may seem big because the diagram is all dissasembled... but does the pilot volume make a difference?

[deathbyDWV]

Oh yeah... I forgot to mention that crowley...

If you didn't know already, a smaller pilot volume leads to faster piston opening time and more power.

[Gun Freak]

ohh. thanks. maybe i wont put the whole stock deal, just the ball valve right after the Tee that houses the schrader?

[MrCrowley]

You'll notice not every fitting will fit together perfectly, so if a fitting can only fit halfway in to another fitting, this creates more volume. Yes, the pilot volume is quite essential to making a good valve. If you have a big enough pilot valve, it doesn't matter so much. Just remember the smaller pilot volume you have, the faster your valve will open.

If your pilot volume is too big, your pilot valve too small and your piston isn't sealed with o-rings, your piston might not even open at all.
Just something to keep in mind.

[deathbyDWV]

The stock is fine.

Your pilot volume is what is between the back of the piston and the front of your pilot valve. That is what you want to make smaller.

[Gun Freak]

this is my first day on spudfiles... sorry for being stupid
the pilot volume is to the left of the ball valve right? so if i put nothing behind it it will open quicker?

[MrCrowley]

No worries, we don't mind helping everynow and then

The pilot volume is between the piston and the pilot valve. The pilot valve in this case is that 1/2" ball valve you have. Anything on the left side of that ball valve doesn't matter as long as it can allow air to escape in to the atmosphere.

Just remember that the faster you can get the air pressure in the pilot volume out in to the atmosphere, the faster your valve will open. Ways to do this are; you need to minimize the pilot volume and maximize the pilot valve. Or you can do one or the other, big pilot valve means you can have a big pilot volume. Small piot volume means you can have a smaller pilot valve.

Just build your cannon how you think is right, and then if you have troubles with the piston later we can sort that out.

[deathbyDWV]

No, your pilot volume is to the right of the ball valve.

And don't call yourself stupid. You are just new and un-informed. Not stupid.

Edit... Beat me to it crowley.

[Gun Freak]

Alright. I just wanted to make the gun the best it could be. Thanks so much for your help

i will take your comments into consideration. how about i redesign it then you can tell me if its better?

for now i got to go

thanks again

[Gun Freak]

i've been thinking... i cant think of any ways to get less pilot volume... because i have to pump it up through a schrader that has to be to the left of the piston so it can push it into the barrel, right? so how am i supposed to lower the pilot volume? i may use metal fittings, which may help... but will that be enough?

[deathbyDWV]

You could just screw the schrader straight into the side of the PVC male adapter on the right of the ballvalve. As long as it is through two layers of PVC, it will be plenty strong.