Pneumatic cannon.

[BaDSeeD]

How ya doin guys. I've been away for quite a long time, but I have some free time tonight, and thought I'd look around.

Anyhow guys I am interested in making a pneumatic cannon specifically for playing splatball, but it has other options, simply whatever ammo you decide to put in it.

I was looking around a few different sites and came across this one from tippman.

<a href="http://www.tippmannexplosives.com/" target="_blank">http://www.tippmannexplosives.com/</a>

It has a hell of a lot of cool shit for anyone interested in paintball, unfortunatly, unless your military, or law enforcement, YOU CAN'T HAVE IT!

Really pisses me off.
Anyway I want to build the grenade launcher they have listed there.

<a href="http://www.tippmannexplosives.com/newpages/grenade_launchers.htm" target="_blank">http://www.tippmannexplosives.com/newpages/grenade_launchers.htm</a>

Most of it seems pretty simple except for the valve assembly. Does anyone know of a valve that would be suitable for something like this? Even an electrically operated valve would be suitable, but it has to be able to release a large volume of gas (co2) quickly enough to get a decent speed out of the projectile.

Any help would be appreciated.

By the way, I havn't been around for a while so I'm not sure if this still falls under improvised weapons or if it should be in another section. So be gentle NBK if I made a mistake.

[Bignutsami]

Hi..
Sorry, your links you gave keep timing out for me so i cant comment on them.

<a href="http://www.valuelinx.net/~dthames/spudguns.htm" target="_blank">http://www.valuelinx.net/~dthames/spudguns.htm</a>

Gives a design for a piston type valve that is suposedly one of the fastest. It also has some great mpegs to download.

You could always just use a solinoid valve for electrical firing which is far easier then the piston.

<a href="http://www26.brinkster.com/fullauto/index.html" target="_blank">http://www26.brinkster.com/fullauto/index.html</a>

has a design for an auto using solinoid valves. If you fitted this to a regulater feeding CO2 you would end up with a serious rapid fire grenade launcher, though a regulator aint fast enough for full auto it will allow far more shots at consistant pressure.

Im not sure if solinoid valves make for a more powerful gun then a ball-valve, but electrical firing wont screw up your aim when you fire it.

[RTC]

They time out for me as well..

[xoo1246]

<a href="http://www.tippmannordnance.com/index.htm" target="_blank">http://www.tippmannordnance.com/index.htm</a>

[BaDSeeD]

I'll have to look into those types of valves.
The links seem to work fone for me, but i am also on a cable... maybe thats the difference.

Anyhow look at the crap on that site if you have a chance, who would have thought someone would mke a full size howeitzer for paintball!!!

[BaDSeeD]

Ok I looked at those web pages, and I was hoping for some kind of valve that I could just buy. I'm going to be making everything else for it, I was hoping to not have to make the valve as well.

As a last resort I WILL make one, but I'd prefer not to.

Money isn't a probelm with all the overtime I have been putting in lately. And it would sure save time to be able to buy the valve.

[Anthony]

Don't know if it's what you are looking for, but if you want a bought solution a SGTC Supah Valve might be suitable:

<a href="http://www.spudtech.com/supahvalveprod.html" target="_blank">http://www.spudtech.com/supahvalveprod.html</a>

[Energy84]

Has anyone got the SupahValve? I'd really like to know how it works because I don't exactly have that much cash to spend on a starch abuser but I do have access to lathes and milling machines :)
Photos of the inner workings are much appreciated.

[BaDSeeD]

Wow, that valve looks good for other applications, but its friggin huge.
I'm looking for something a lot smaller that i could use in a launcher that would be mounted under the barrel. I'm looking specifically for a valve that would be mounted to a piece of 2.5 inch pvc pipe, with a barrel length of about 10 or 12 inches. I want that to be able to launch a paint filled ballon from a cardboard sabot at a velocity between 150 to 300 fps. Somewhere around 200 fps would be ideal. Looks like I'm going to have to make the damned thing after all. Problem is that I don't know much about diaphram and piston valves really to make one of my own. I have seen some information on how they work, but it looks like pistons require a fair amount of travel before the pressure is released, so that wouldnt work too well with a trigger for example, and diaphram valves i simply dont understand well enough (yet) to make one.
Thats why i wanted to skip this process and just buy one.

Anyway thanks for the info so far guys. I'll keep checking here to see if anyone has more info to offer.

[Anthony]

The commonly used 1" sprinkler valves work use a diaphram valve. The solenoid is simply used to break a vacuum allowing the diaphram to move and let the air or water flow. You don't have to use the solenoid if you don't want an electrical system, there's a manual lever built into the valves. Or, better for a trigger setup, screw a pipe nipple into where the solenoid fits (it's threaded) and run a piece of thin bore flexible hose to a push-button type valve which is either your trigger or is activated by the trigger. It just needs to vent the space above the diaphram to the atmosphere to activate the valve.

[BaDSeeD]

Thanks Anthony. I had read somewhere that someone had used a valve like that for potato guns or some shit before. I just wasn't sure how much pressure one of them could take and what kind of velocity I could expect out of a valve like that.

[Prodigy45]

The best plans i've seen for a potato launcher is this one:

<a href="http://members.aol.com/sph911/spud/pneumatic.html" target="_blank">http://members.aol.com/sph911/spud/pneumatic.html</a>

The sniper rifle one, but be ready to invest some money in it because when all is said and done it' woukd cost over $100.

[BaDSeeD]

Hey Anthony I found a site that had some information and pricing on sprinkler valves.
It also poses a new question. Anyhow the site is here..
<a href="http://store.professionalsupply.com/cgi-bin/wfp55389.storefront/3c9502b8013b53c82755d8f5a506064e/Catalog/1042" target="_blank">http://store.professionalsupply.com/cgi-bin/wfp55389.storefront/3c9502b8013b53c82755d8f5a506064e/Catalog/1042</a>

It says that some of the valves are specifically designed to close slowly to avoid what they call "water hammer" which I am fairly certain is just the pressure spiking on the pipes if it is shut off real fast. Anyhow if I were to use a "slow closing" valve in this kind of application, odds are I'd empty my air supply in one shot.

Does anyone know anything about these valves? It dosn't specify that the smaller valves have this feature, but I don't know that for sure. We got a farmer Brown around here that might know something about these valves?

[BaDSeeD]

Well before even starting I've come to the conclusion that this thing is going to be too big and heavy to mount under the barrel. I think I'll make it as a seperate gun like an M-79. No point in throwing off my aim and handling of my gun by putting this big heavy thing on it.

[Ctrl_C]

that supah valve is awesome...too bad it costs $100. that site also has rifled barrels that claim 50% greater accuracy. i think i may soon order the supah valve with pnuematic trigger actuation, a 4 foot rifled barrel, and a bbq ignitor for a regular spud gun.

[Anthony]

I have to admit that I have no idea how fast the valves close, I've only ever used them to dump air. To be honest, I'm not sure that any/many solenoid valves available would be capable of opening fully and closing again quickly enough to give multiple, decent pressure shots from a reservior. If you don't have a seperate reservior and shot chamber you might need a spring loaded manual valve activated by a falling hammer or other kind of spring propelled mass to momentarily knock the valve open and release a blaat of air.

Not sure if it will be of help but I've got some info on my delapidated website about a potato gun I made with one of these sprinkler valves:

<a href="http://www.geocities.com/spudguns_uk/plastic_rifle.htm" target="_blank">http://www.geocities.com/spudguns_uk/plastic_rifle.htm</a>

[BoB-]

Here are a couple of cannons designed for paintball;

<img src="http://www.pukindogspaintball.com/cannons/MVC-082S.jpg" alt="" />
<a href="http://www.pukindogspaintball.com/cannons/BECC.htm" target="_blank">http://www.pukindogspaintball.com/cannons/BECC.htm</a>

<a href="http://www.pukindogspaintball.com/cannons/cannon1.jpg" target="_blank">http://www.pukindogspaintball.com/cannons/cannon1.jpg</a>
<a href="http://www.pukindogspaintball.com/cannons/BECC2.htm" target="_blank">http://www.pukindogspaintball.com/cannons/BECC2.htm</a>

The breaches are shit, but they both use Co2 for constant pressure, just dont forget the safety release valve and you could fire dozens and dozens of grenades.

[PYRO500]

I think that valve is just a piston valve, there's an air space at the top and there's a piston that allows air to flow through when the piston has traveled all the way, opening a valve to the top relieves pressure in the chamber thus making the piston move letting gas escape.

[PYRO500]

After some carefull searching I found a place with plans for the "supah" valve check this page out:
<a href="http://www.geocities.com/jr_cross00/cannon.html" target="_blank">http://www.geocities.com/jr_cross00/cannon.html</a>

it is fairly simple design, when I get some cash expect pics.

[Ctrl_C]

bastard...i just ordered a supah valve. oh well...not my money. my gun is 6 feet long and weighs 15 pounds. it is very similar to the one shown <a href="http://www.spudtech.com/9302.html" target="_blank">here.</a> I am waiting for the valve as we speak. I still need another 2" union (I modified the design to be able to take the valve off easily) and it will be done. I will post pics when it is fully put together.

[Energy84]

Sweet! Thanks pyro! looks like I know what I'm doing in shop class now :D

[Ctrl_C]

I just made my cannon with my SGTC Supah valve, but it leaks. It will still shoot a potato really high and far...i mean, i'm tempted to take out the annoying low flying medical helicopters that fly over my house with this thing...it could.

the problem is that there is a 4" dia 26" long air chamber that the barrel goes through. The barrel is completely independent of the chamber except the fact that it goes through the chamber. The chamber needs to seal on both ends with the barrel going through the middle. Right now I have a 4" x 2" bushing that I sanded the pipe stop out of with a dremel. Apparently it didn't seal. I need a way to get it to seal on a new one without using the dremel to jerry rig something together. I don't know much about what kinds of pvc parts are available but if anyone has any ideas, please let me know.

<small>[ March 30, 2002, 12:16 PM: Message edited by: Ctrl_C ]</small>

[Spudgunner]

Wow, I haven't posted on here in forever. Anyway, my suggestion (I just made it up, it may or may not work) is to find the parts that are leaking first. Then, take some slivers of PVC and dissolve them in the PVC glue (since that is how it works, by dissolving the PVC). Then, if you can, paint on the glue/PVC mix onto the parts that are leaking, and it might leave PVC in the cracks that aren't sealed. I don't know whether this works or not (in fact, I don't know if you can even tell what I am saying), but it is worth a try.

Spudgunner

[Ctrl_C]

I understand and that is an excellent idea. I will try it tonight.

btw, I can shoot potatoes an estimated 700ft high.

[AcridSmoke]

I've made a couple of cannon myself, and have never used a supah-valve. At 80 PSI, we usually achieve a 400 yard shot with a potato with both solenoid and ball valve cannon. We're probably going to build an exhaust valve-based launcher. Specifically what PSI are you using with your supah-valve for the 700 ft shots?

[Ctrl_C]

hard to say. it leaks and I don't have a guage but the air compressor is pumping 120psi in there. This shot was straight up, not angled.

EDIT:

<img src="ftp://ewf:df447jh4@209.195.155.80/Hosted%20Images/spudgun.jpg" alt="" />

<a href="ftp://ewf:df447jh4@209.195.155.80/Hosted%20Images/spudgun.jpg" target="_blank">Spudgun</a>

<small>[ March 31, 2002, 03:15 PM: Message edited by: Ctrl_C ]</small>

[RTC]

Nice car..

[Ctrl_C]

not mine but thanks. i took it like that to get the truck in the picture for the bunker thread.

[AcridSmoke]

Well, I finished a fully automatic marble gun of my own design with a 50 round clip... Lovely...

That figure of my distance was at a 45 degree angle. What's yours? My current project is a breech-action paintball shooter.
The automatic uses a system where the marble is struck with extreme force from a piston in the rear. It shoots a good 150 feet at a slightly above flat angle, having a rate of fire around 1000 RPM. Fun stuff.

<small>[ March 31, 2002, 11:08 PM: Message edited by: AcridSmoke ]</small>

[PYRO500]

Well then post pictures plans or something similar so we can see your disign/device in action. I really doubt you got a 1000 RPM fire rate, that is faster than marbles will fall from a hopper and it is faster than most machine gun manufactuers can get their guns to fire.

[BoB-]

Sorry to go OT, I got here late.

Ctrl-C
if it still leaks, I'd try ordinary hotglue (high-temp), Its amazing how much pressure hotglue will take. Provided you make a nice uniform seal it should hold. Anthony did this on his page here;

<a href="http://www.geocities.com/spudguns_uk/1_5_abs_combustion.htm" target="_blank">http://www.geocities.com/spudguns_uk/1_5_abs_combustion.htm</a>

[Ctrl_C]

Well, I don't need to worry about leaks now because it just exploded. I lost a 2" male threaded coupling, a 2" union, and 2 elbows.

It deafened me for 2 mins and the plastic cut my neck and arm and something hit my thigh and scraped it up.

I'll go get new parts maybe tonight. It looks like the glue joint between the pipe coming off the T and the street elbow failed. The pressure escaping caused it to leverage off the male coupling, breaking it.

[RTC]

Nasty, hope ya heal well.

[Anthony]

Scary considering your plastic plumbing in the US is at least twice as thick as the stuff here, yours is pressure rated too. /me wonders why he is still alive...

Leaks are a bastard, hotglue can help, but it doesn't seem to work too good for sealing a seam, the pressure just seems to lift it slightly and squeeze around the join. Sometimes it's better just to say "fuck it", hack off the joint and slap a new one on, even if it does make your gun shorter than it should have been.

[Mr Cool]

Haha, I love that attitude Ctrl_C -

"It just exploded and nearly killed me. I'll go get parts for a new one tonight."

:) :)

[AcridSmoke]

Ow. Heal up. I've only had one of my creations explode ("The Big Cow"). It was an over-under style launcher. The 180-degree turnaround at the back blew up into three parts and most of the gun flew backwards... My friend was next to me at the time. It was really loud, but no one got hurt at all. I just got kind of mad at myself for forgetting to put the brace between top and bottom for stability so I could specifically prohibit what had just happened.

My automatic fires 960 rpm, I am dead serious. We use a spring-fed magazine, so the speed of gravity is no problem. The piece that hits the marble to propel it is made of hard and thick plastic, yet it remains at a small weight, so the rate of fire is insane. It's only ever jammed once, I believe, and it cleared up very quickly. I'll try and get a link out to an animation I just finished of it as soon as possible.

<small>[ April 01, 2002, 10:01 PM: Message edited by: AcridSmoke ]</small>

[Bignutsami]

_C:

What class pipe are you using?

Did you make sure your using the pressure glue, not the standard stuff.

Pictures of pieces maybe ??? :)

Anthony:

England would probably use the same system as Australia wouldnt it, the PN rated system. Im sure there would be pressure rated pipe there somewhere.

The American system isnt rated on pressure rather on wall thickness, whereeas the PN systen is rated on pressure in Bars (PN12 = 12 Bar = approx 150psi).

Its kinda easier to rig the system up to be capable of the same pressure with the PN rated stuff, but the Americans have sch80 and sch120 which hold more pressure then ours, Our system goes into polyethylene pipe after the pressure goes above 18bar (250psi).

[Ctrl_C]

i was using schedule 40 rated to 220 psi i think. the glue joint failed however. i picked up some "heavy duty" pvc glue and the necessary parts and put it together approx 3 hours ago. I will wait until at least morning and possibly tomorrow night until I repressurize it.

[BoB-]

I had several PVC spudguns blow up on me, so now I only use empty high pressure gas cylinders. You can pick up old fire extinquishers at the dump, grab a few of them incase one leaks, they may not be safe enough to hold 250psi for several years anymore, but I've shot sparkplugs at over 210psi using a fire extinguisher as a chamber. And because everything screws together, if you use a mile or so of PTFE tape, it will never leak on you. But I hear those 'Supah valves have a low maximum psi...

[Anthony]

You can get pressure rated PVC/ABS pipe/fittings in the UK but it's for specialist applications and not used for regular plumbing, anything holding pressure is either copper or steel/iron. The stuff I use is not intened to hold any pressure, well maybe that of a few feet of water, but that's about it, holds up well at 250psi though...

[Ctrl_C]

I rebuilt it last night, let the glue set up about 14 hours, and fired it about a half hour ago. Everything seems good. I had it up to 110 psi, 10 more than the valve is rated for. I hit a wheelburrow at 40 yards. It deted it badly and the power hitting it was incredible. My new favorite projectile is caulking tubes. They fit very well and are front heavy so they hit the ground tip first and bury themselves halfway into the soft dirt. It's all set up right now to be able to fire in a couple seconds notice of a heli flying over. I hate the heli's...they fly at about 400 feet (well within the reach of my newly acquired "anti-aircraft gun") and are loud as hell, shaking my house. Oh great fun today, beautiful day here too...great for heli shooting. :)

EDIT: After a week or so of testing: excellent results. Potato has an estimated range of .25mi laterally, 700 feet vertically at 45*. Potatoes dent 1mm aluminum 6" off center at 40 yards. New favorite projectile: empty plastic caulking tubes. Shoot very fast and straight, good fit. Put one through 3/4" Oriental Strand Board (similar to plywood) at 70 yards. VERY impressive.

Also received full 5# CO₂ bottle for portable air source. Will hook up some time this week.

<small>[ April 09, 2002, 12:19 AM: Message edited by: Ctrl_C ]</small>