Old School Pneumatic 18mm Ball Valve

[littlebro05]

Hey spudders,

It's been while since I've posted anything up on here, and this time it isn't airsoft! It's my first pneumatic! Next holidays I'm going to be working on MRR aka MrRedRooster's piston valve gun since it seems so easy to make. And finally I've figured out this quote from some guy "spudgunning is like doing it, once you've tasted it you want some more"... was gonna say the word but it was abit rude:

Statistics:
Trigger Activation = opening ball valve by hand (I'm too lazy to improve that to the spring loaded one, since I'm going to be working on the piston valve one, so it doesn't matter.
Ammunition = AA batteries (wadded with tape), shotgun shells (loaded with metal bits), wadded nerf darts.
Pressure Operation = 80PSI
Air Chamber = 2L Coke Bottle
Ball Valve = 3/4"
Barrel = 18mm ID, poly resin screw on barrel.

Notes:

If you can see I have a piece of bolt stuck right in the middle of it... previously my air bottle has popped off so I figured if I drill and jam it with a teflon'd up bolt thing it pop... and it hasn't so either.

It leaks at approxmately 60PSI... but it doesn't leak badly at 80PSI... when I shoot it I have it at 90PSI so by the time i get read to shoot
it should be at 80PSI.

And some pictures!

The Air Gun






The Ammunition






Shooting montage with damage

[youtube][/youtube]

Tell me what you think. Constructive criticism if need be.

[Pyro Ninja]

15mm Poly pipe fits AA batteries Perfectly, no tape required-I recommend you go and get a length of it.
But yes, nice simply launcher-thumbs up

[Carlman]

lol you realise if you had of simply had the same length of poly as a chamber aswell with a cap on one end with the same scrader you would of had a perfectly safe gun able to handle 150 or more?

[Technician1002]

I like it. It seems to work well. The pop bottle is a little scary as it looks way to thin compared to the other parts. I have some pop cans here that look a lot like the ones in your video. If you don't damage the barcode, you may be able to get your deposit back Do you have deposits there?

Have you tried range testing marshmallows?

[CpTn_lAw]

Well, this is a pretty decent first cannon, i'm happy to see you got it well! The damage is pretty good considering it is a ball valve. Try and go to a piston one, you'll see what power means and you'l want MOAR!!!!!!! ^^

Have fun, play safe

[King_TaTer]

Not bad. Simple yet effective. Can't wait to see your piston gun. Good job.

[littlebro05]

lol you realise if you had of simply had the same length of poly as a chamber aswell with a cap on one end with the same scrader you would of had a perfectly safe gun able to handle 150 or more?

Trueee.... o.O, although wouldn't the chamber to barrel ratio be 1:1... I guess it wouldn't matter if your taking it up to high pressures... looks like I need to figure out a shock pump <,<. It'd be funny looking though lol... It'll look like the light saber Darth Maul uses.

The pop bottle is a little scary as it looks way to thin compared to the other parts.

Nah, even though there is no surefire way that coke bottles have a decent pressure rating I've used most bottles up to 100PSI (when I get scared and give up) and they've never blown up on me... The only reason I wouldn't it would blow up on me is because if it was exposed to the sun for too long or heat.

Sadly I'm going to be using a coke bottle too for my piston gun . Oh well. The bottle I can take off any time since its stuck to some fittings not the ball valve itself, it's probably the advantageous thing about fittings XD.

Also another depressing thing, I got recently scolded by my older brother he pays my school fees about me failing physics and telling me how I don't have a future if I don't pass it . I'll probably won't work on my piston gun till mid year, since I have no more cash left and my brother .

[jonnyboy]

The pop bottle is a little scary as it looks way to thin

It may look thin but I've pumped them up to 120 psi and shot them with a bb gun. A low powered shot with a pellet won't pop them.

So yeah I would use one as a chamber.
Although in teh land of cheap pvc why would I?[/i]

[Carlman]

Ive made the gun before with 2 lengths of poly risers one for barrel and one for chamber and it was great to shoot, 1:1 is perfectly fine for pnuematics

[Mitchza89]

Ah how that brings back memories. My first gun was the exact same as yours mate .

You'll start to get hungry for more pressure, and better performance. I thought my gun was always going to stay as a bottle, BV and a barrel, now i'm pushing 500psi and using machined aluminum pistons in all metal piston valves. Trust me, you'll get there eventually.



...Everyone does

[Sparkie]

"Don't forget the aerogard and have a good weekend"
That's all I can say

[limbeh]

My first gun was exactly the same, just that I used a metal ball valve instead. It is being phased out in favour of those with chambers using PVC pipe.

As for the bolt, there is another way (sorry JSR for stealing your line): Epoxy. File off the threads, then find a threaded fitting that fits, epoxy and stuff the bottle in. The bottle neck tapers so size isn't a problem. Has worked fine for at least 250 shots and counting on at least 3 guns.

The advantage of using threads is that the chamber, valve and barrel are detachable. If a round jams, we can simply detach the barrel, release the air, and clear the barrel in peace. The other advantages are they're much easier to transport and we can mix-and-match barrels and chambers as we please.

In my country, 13mm PVC AE pipe fits AA batteries snugly - they don't even go down the barrel at normal speed when we load them because the air can't get out fast enough.

[littlebro05]

The advantage of using threads is that the chamber, valve and barrel are detachable. If a round jams, we can simply detach the barrel, release the air, and clear the barrel in peace. The other advantages are they're much easier to transport and we can mix-and-match barrels and chambers as we please.

My bottle and barrel is detachable too, I just don't deattach the bottle because it's wayyy to hard to since the threads are in there real tight. The barrel comes off with easy. If you notice though, I have a bolt drilled in. It's too keep the bottle from flying off and it works really well... I also filled it up with epoxy but it isn't obviously enough but oh well... I still have the gun, but haven't fired it in ages.... it's only fun firing it with friends.

[limbeh]

My soft drink bottle guns have all been phased out. The barrels have been used for other guns, while the chambers are now used to test ball valves to check that they aren't leaking.

So far the epoxy has never failed me. I used Araldite epoxy at first, then once I got my hands on West epoxy (thanks to JSR for input) I never looked back. So far it seems that the at pressures of 150psi or less, epoxy can hold the load well, provided you put enough. When in doubt spam more.

Mine is up here: http://www.spudfiles.com/forums/simple- ... 17343.html. 10 minutes work and a few days searching the hardware district just to find PVC primer.

[Stolly32123]

ur a bit close to the target. move furthur away next time.