SpudFiles

In this valve, the chamber is sealed off by the bolt, when air is injected behind the bolt it is pushed forward and allows the chamber air to vent through the holes in the bolt, after the bolt slides all the way forward the bolt air is vented through a hole and the bolt moves back under spring pressure.

If built right it should work.

If I can get a hold of any O-Rings I might build this. I have a few 1.5" Tees and about 3 feet of 3/4" PVC. I also have to find something good for the bolt, a small size pipe with an endcap perhaps?

Where does one find O-Rings?

1/2" pvc, put plenty of tape on and you can actually use the tape to make oring grooves i think

Cool. I just had an idea, put a pop-off valve between the bolt chamber and the main chamber, once the chamber reaches a certain pressure it will open the bolt, the bolt won't need too much pressure to open, just enough to overcome the spring.

I'm probably going to build the valve out of a 2" Tee and use a 1.5" bolt, have the front part of the bolt female threaded so I can just screw on a smaller bolt to the end of it for paintballs.

You can order O-rings from mcmaster. They have every size, shape, and material o-ring you could ever dream of. That's where I got my 3" ones from. You can also get smaller sized ones from Autozone I'm pretty sure.

Does Autozone have 1.5" O-Rings? My brother should know he works at a car dealer's garage, he's a Porter/Mechanic.

All I know is that when I asked for 3" o-rings the guy looked at me like I was crazy and said that he didn't have anything near that size.

Do O-Rings stretch very much? That would make it easier to find a fitting O-Ring.

Depends on the material, but ya, a little.

So I need at leats 2 O-Rings. Maybe I could make some by rolling up elctrical tape, that stuff is part rubber, I know you can roll it up, maybe even a chunk of rolled up intertube which I have.

Yes, always use smaller o rings so they are less likely to slip out of place.

1.5" pipe... hmmm... could you build it in sdr 21? I have some O-rings, nominal outside diameter of 1.625", that you could use in that case.

1/8" thick, and made of viton... excellent stuff.
Email me if you want me to drop a couple in an envelope and mail it to you.

Are you saying make it out of a 2" Tee with Sch80 Pipe with a bolt made out of 1.5" SDR-21? Basically a golfball barrel, that would make it easy to load golf balls.

No, the 1.625" is an OD. You'd make a piston that would slide in the sdr 21. Stretching it to the 1.9" or so required to make it fit in 2" sch 80 isn't recomended.
I do have some viton O-rings (3/16" thick) which would work well in 2" sch 40 pipe, but they'd cost a bit more, about 1$ a peice plus shipping.

As to making it fit in 1.7" ID pipe, 1.25" pipe is a good enough fit to work (.02" clearence on the side, or a bit more than twice what I typicaly use.)
If you machined it in sch 80 pipe of that diameter (wall thickness = .191") you might be able to get away with it, as you'd have about .092" of material left on the inside assuming 5% squeeze. However, that's pushing it, so I'd try epoxying a lathed-down fitting or such in there to make it thicker in the area you are working.