Large Inline Ball Valve Cannon

[DYI]

Improvements:better valve
bigger chamber
longer barrel
better paint job
Better valve is the most important of those, followed by better paint job (it really does look pretty hideous)
Some day when you post a cannon with 20 000 cubic inches of chamber volume, a piston valve in an 6" tee, and a 50' barrel, running on 600psi hydrogen, which can achieve 140 000 ft/lbs of energy with a 1 pound projectile traveling at Mach 2.3 and it only gets 3 views, you'll know that it is because people thought it was just another tiny ball valve gun.

[666lucky693]

well the valve is really good it opens really fast thats y i bought it the paint job was good it was a winter camo paint job it just got scrached off what size of chamber should i have and what size barrel i was thinking about making the chamber bigger and what size of barrel

[DYI]

That all depends on the amounts of portability, practicality, power, velocity, and time/money consumption that you want.
The valve may seem good, but enter the specs for this cannon into GGDT with the ball valve, and compare that with what a sprinkler valve/piston valve/burst disk valve, and you will see the performance increase.
I doubt that you can open it faster than 100ms, whereas a good piston valve can open in 5ms, and a burst disk can open in less than 1ms.

[jrrdw]

o well sry is there any improve ments i could make

Use a sprinkler valve instead of the ball valve. You could switch to a brass ball valve, if your intent on useing a ball valve. Spring load it.

[666lucky693]

i know what u mean but i compared my valve to a brass one and it opens faster thats y i chose it over a brass one

[spud yeti]

To make it more practical, why not make it an under-over design?

[666lucky693]

i all ready thought about that and i just might

[666lucky693]

here is the new ammo and damage it does

[spud yeti]

The ammo looks pretty cool, but how far away did you shoot the can from?

[666lucky693]

point blank so i didnt lose it it went the whole way thru and bounced back so it could do more damage but right now i cant do much the pump broke again and will only go up to 100 psi so yea once i get a better pump i can show what it really can do i will try to get it up to 300 psi it should do better at that pressure

[spud yeti]

Hmmm, 300PSI in a PVC pipe, I don't know how smart that really is. I know the pressure ratings and all that, but even so. Maybe you should think about a copper gun if you like high pressure?
Do you use a sabot with that ammo?

[666lucky693]

so u dont think it will hold up at 300 and i dont sabot the ammo it fits perfectly in the barrel and i put the bolt and washer to keep air from going thru it

[spud yeti]

Well I dont know how well your joints have been welded and what pressure rating your pipe is, but I definitely wouldnt do it too often. Maybe thats just me though
And PVC schrapnel isnt fun...

[DYI]

Where did you find a PVC ball valve rated for 300 psi? I have never seen them rated that high.

If the rating for all chamber parts is over 300 psi, then you theoretically should be fine. I personally wouldn't do it, because if you happen to have a microscopic defect in the pipe (which can and will cause failures below the pressure rating), you could end up with some pretty nasty shrapnel and hearing loss issues.

What exactly is that ammo? Have you ran it through GGDT to find out its velocity and muzzle energy?

[spud yeti]

Where did you find a PVC ball valve rated for 300 psi? I have never seen them rated that high.

Wow, I didnt think about the ball valve. Not worth the chance: build a copper gun