My New Pneumatic Cannon

[tony48]

I am going to be making a new pneumatic cannon soon. I have only made a few cannons before, all out of PVC. One was a simple combustion and the other was a pneumatic with a ball valve. Here are my problems.

1) For my next cannon I want to use a sprinkler valve. I understand how to modify them and everything but I was wondering if I could find one that is bigger and still easy modify. I am planning on interchangable barrels (screw on type) up to 1 1/2 inches and maybe bigger. I think that the small 1" and 3/4" valves would constrict airflow a little to much. I can't seem to find a bigger valve on the internet for a reasonable amount of money.

2) I want to make the cannon(chamber and barrel) out of metal so I can pressurize it more. How would I attatch the metal air chamber to the plastic sprinkler valve? Is there another valve option that I can use? I don't want to make a piston valve or use a ball valve.

3) I would like to know how to make a good breech loading mechanism. With my old cannon (8 foot barrel) I got tired of muzzel loading it.

Thank you to all who help.

[jrrdw]

No Jimmy Johnson fans allowed, just joking. McMasters sells QEV's, if you got the money, your asking for a tall order -- big cheep valve. We all want that. Use threaded adapters to attach PVC to metal, pipe threads is pipe threads, use teflon tape to seal the threads.

Do some looking around for the info on breech load building, it's all in here.

Welcome to Spudfiles.

[STHORNE]

you could just make your own piston/coax.. I know its a different concept but its limitless to pipe sizes/air flow.

also, better performance (from what I've read/seen)..

[jimmy101]

... I want to make the cannon(chamber and barrel) out of metal so I can pressurize it more. How would I attatch the metal air chamber to the plastic sprinkler valve?

If you use a standard plastic sprinkler valve than there is zero advantage in using metal for the rest of the gun. The system is only as strong as the weakest part. Sprinkler valves are designed for ~60PSIG nominal and probably pressure rated up to perhaps ~120PSIG or so.

Standard pressure rated PVC can be pressurized to higher pressures than the plastic sprinkler valve.

[watto]

Looks like your doing the same as I did, first ghetto combustion guns then a ballvalve gun then a sprinkler then finally piston guns which is where I'm at now, might I suggest you skip the middle step and go straight to piston guns? coaxiles are just as easy as your average sprinkler cannon plus they are cheaper and way more powerful.

If you really want to use a sprinkler, why not use 2 one inch sprinklers actuated by the same blowgun? Cheaper than buying a 2 inch one.

If you want a metal chamber use a fire extinguisher, you can get copper fittings that screw from the fire extinguisher into the sprinkler, but theres no point having a metal chamber with a sprinkler valve, I wouldn't take my sprinkler valve past 140 or so.

[Tooo Easssyy]

(dont know about your first question sorry)

but with you could use a copper fitting from the metal chamber to the plastic sprinkler valve, it would be the easiest and cheapest way to do it i think.

and with your 8 foot barrel check out this website it might help, i did for me

Tooo Easssyy


http://www.advancedspuds.com/breech.htm
http://www.advancedspuds.com/interchangable.htm

[tony48]

I think I will just make a piston valve out of a deodorant can like the sticky of that sniper. That breech loading idea that someone linked me to looks good. I think I will make my breach loader like that. thanks to all for your information. I would not understand alot of this stuff if it weren't for this forum.

[watto]

Yeh some deoderant cans fit well, but you have to fill them with glue or epoxy or something similar for strength, which makes them quite heavy. You could use a pvc coupling like I have, theyre very strong and easy to sand to the right size if you jam it on a drill. I just finished my new golfball piston cannon about 15 minutes ago, now comes the agonising 48hr wait for the cement to cure