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Bike tire valve on pneumatic gun

Posted: Thu Mar 21, 2013 9:20 am
by spudzooka98
I was wondering if I cut the tire valve of a bike (sorry I do not know the technical term) I could put it on a pneumatic cannon. My plan was to take 1.5 inch pvc for the chamber and have a threaded end cap on one side with the bike valve in the cap a reducer into a ball valve and a 3/4 inch barrel. The barrel being 24 inches long and the chamber being about 1 foot long. Does this sound like a good plan?

Posted: Thu Mar 21, 2013 9:22 am
by spudzooka98
Or any suggestions to improve it also the 1.5 pvc says it can max opperate a 330 PSI :)

Posted: Thu Mar 21, 2013 11:25 am
by Brian the brain
I was wondering if I cut the tire valve of a bike (sorry I do not know the technical term) I could put it on a pneumatic cannon. My plan was to take 1.5 inch pvc for the chamber and have a threaded end cap on one side with the bike valve in the cap a reducer into a ball valve and a 3/4 inch barrel. The barrel being 24 inches long and the chamber being about 1 foot long. Does this sound like a good plan

Or any suggestions to improve it also the 1.5 pvc says it can max opperate a 330 PSI
Not a good plan at all.
But we've all been there.

PVC is meant to be used in a fixed position.
The way we use is means it is exposed to different forces on top of the pressure.
Rapid depressurisation, knocking it accidentally, moving it around, recoil etc.
It is therefor recommended to stay BELOW it's pressure rating.
Now...you suggest using some pretty high pressure..this means you're after a powerful shot.
The ballvalve you mention will not give you the kind of performance you are after.
Go through the pneumatic cannons showcase section and learn about other valves, such as QEv and piston valves.
They will outperform a ballvalve at even a much lower pressure.

Another bad idea would be to use a screw-on cap.
Only use pressure rated ( at the right number!) PVC and solvent weld the fittings.

before you spend your money on something that fails at the design stage...learn.
Check out the spud wiki and go through topic after topic like we all did to educate ourselves.

BTB.

Posted: Thu Mar 21, 2013 11:38 am
by spudzooka98
thanks so no screw on end cap no ball valve what about the bike pump valve thing would that work for low preasure like 100psi or 80psi also ii was not planning on using 330 psi in it i was just mentining it. i was planing on about 100psi

Posted: Thu Mar 21, 2013 11:47 am
by Brian the brain
It's been done before, just did so a couple weeks ago.
The PVC I used was rated to 16 bar and only 25 mm though.
It works..

BUT:
Might I suggest using a ( internally)threaded reducer- and going brass from there?
Say, 1" or less..
Then put the bike-valve in the brass fitting so you can change it out if you need to.
If you like you can use a Tee instead of this fitting and install gauges or whatever suits your needs later without having to chop up the cannon.

Screw-on endcaps are usually DWV ( non pressure) PVC.
I know they sell pressure rated reducers wich allow you to go from PVC to brass fittings.

Posted: Thu Mar 21, 2013 11:53 am
by spudzooka98
thanks good idea i will probobly do that but still brainstorming you know

Posted: Thu Mar 21, 2013 1:19 pm
by Brian the brain
I storm sometimes...yes... :D

Glad I could help..

Posted: Sun Apr 21, 2013 3:49 am
by Buntyspudbaby
Id"e also like to add I noticed a hairline crack in a pn18 20mm to 40mm barely used for a small standard combustion. Using pn12 40mm pipe to touch the reducers in the middle. Re-iterated basically PVC isn't meant for combustion spikes.