TCBC-First Pneumatic cannon

[strangers]

TCBC
Tri-Chamber Ball-valve Cannon
Specs:
Resevoir- 16.p Fl. oz. pop bottle x3 plus several lengths of .5" CPVC and fittings
Valve- 3/4" Ball-valve
Barrel- Approximately 5' of .5" CPVC pipe
Fill Valve- Threaded schrader valve epoxied into 3/4" end-cap.
Running pressure- Around 70-80 psi
Primary ammo- Nails wrapped in duct tape
Style- Over/Under
****All CPVC used in this construction is special Hi-temp pipe rated at 100 psi at 180F****
(That should mean it's rated for more pressure at lower temperature, right?)
The pop bottle were attached with biked innertube then coated with about five layers of JB Weld, then coated with five minute epoxy to seal the leaks. The only one not attached with bike innertube was the MountainDew bottle, I had found an unmarked plastic piece which could screw into a 3/4" female adapter and whose other unthreaded end fitted pop bottle perfectly and sealed with the first layer of JB Weld.
The last leak on the middle Pepsi bottle was recently seal with a single wrapping of duct tape.
With a duct tape nail "dart", it can pierce through 3 3-Subject notebooks before the duct tape stops it.
PICS:

Barrel shot

Chamber shot 1
http://h1.ripway.com/Strangers007/Pics/ ... 000751.jpg
Chamber shot 2
http://h1.ripway.com/Strangers007/Pics/ ... 000756.jpg
Damage Pic

[bigbob12345]

pretty good for a first pneumatic but you should replace the ball valve with a sprinkler valve it will give it so much more power

[Ragnarok]

I would comment, but when I was younger, I was very firmly told not to talk to strangers.

Rated PVC pipe doesn't equate to a lot when your chambers are plastic drinks bottles, because those are the weak links in the chain, and that will always what decides the safe pressures.

[strangers]

Anyway, it's winter and I can't order offl the internet, where do you suppose I could get a sprinkler valve? Cause I can't find them at lowes, but I've already started making a 2" piston valve for my next cannon, which will also have three chambers.
@ Rag- Pop bottles are awesome, they're inexpensive, prefabricated pressure vessels.

[psycix]

Okay it is nice for a first attempt, however, the "network of pipes" that leads to your ghetto chambers constricts flow alot.
And ofcourse the ball valve isnt the best option for a pneumatic.

But you gotta start at the bottom so its a nice beginning.
For your next cannon I recommend to build it with a normal pvc chamber (and use ony ONE big chamber) and a piston or sprinkler valve.

Have fun with your creation

[strangers]

I think I posted this before but,

This what the next one is goona look like, except it will be over/under and have a 2" piston valve. Heres lookin' forward to spring!

[Hailfire753]

For the new plans, you only need 1 pressure meter. Also, get rid of the 3 back ball valves and stuff. put the schrader at the front, between the 3 ball valves and the sprinkler.

Welcome to Spudfiles.

[MaxuS]

You're still going to have to reload it with ammunition each time, so you might aswell just have one large chamber.

[bigbob12345]

Yea I'd go with one large chamber and use an over under design instead.
And one sprinkler valve isnt enough for that size chamber I would recomend either twin sprinkler valves or preferably the piston valve you are working on And you should some wicked power out of that next cannon of yours

Edit:Oh I didnt see at the bottom the thing that said you were going to do an over under design and use the piston valve maybe you could even do twin piston valves which would be awsome but probably not necssesary

[strangers]

Hailfire, what's with the welcome? Little late for that, but I appreciate it. Thanks for making me feel like a noob, lol. But getting rid of the stuff on the back would make it alot lighter.

You're still going to have to reload it with ammunition each time, so you might aswell just have one large chamber.

Maybe not... I'm working on a lever action for my next piston valve rifle.

[psycix]

Lol I can see plans for a "Breech loading hybrid" shine through the page
Youve got big plans in mind eh?

Oh and about your lever action + triple chambers, I dont think it is a very good idea since (like always with multi-chams) you are dealing with flow restrictions.
You could get one HUGE tank instead and burst out with the sprinkler.
I heard it is possible to burst out a lil air instead of dumping the whole tank out with a sprinkler but most people dont know that.

[iknowmy3tables]

the sytem of attaching the bottles seems a little weird, you can buy a pvc cross section, the fact that the size decreses for attaching to the chamber is weird and flow restricting and an easier way of attaching the bottles is just gluing 1/2" pvc into the bottle opening, using cpvc is pointless it's just expensive pvc that it sterile, and can endure heat better.

[strangers]

Did I mention the only thing I had to buy was the ball valve? This was a very cheap cannon. I didn't want to spend any money on the cross.