Pneumatic Snowball Cannon

New England just got it's first snow, now to make use of it. I know a lot of people make Potato guns, which are pretty much the same, but I find shooting food pretty pointless. Snowballs are funner, and less destructive. Your total cost for this will be about $45, if you already have an air compressor. If you don't, you'll have to buy one, which can be costly. I had a compressor, but I just wanted to get a new one.
All the parts used in this instructable came from Lowes, except the compressor. The photos are tagged with the part number and price from lowes.

Gun in action:

Second version gun in action:

IMPORTANT: Skip to last step for a slightly more expensive, but better version.

Step 1 Get the parts

Most of the parts are made by Kobalt, which is the Lowes version of Craftsman from Sears. They're pretty good quality by my standards.
The air compressor was from Sears, it's the Craftsman 1hp 3 gal. Air Compressor.
You can choose to build a 2 inch pipe model, or a larger one, either 3 or 4 inches. You'll only have to get a different size cap and pipe size.

Here's the list from Lowes:
- (Two of these) 1/4 to 1/4 Male coupler - $2.19 - #2270 (Their image is incorrect)
- 1/4 to 1/4 Female coupler - (Not sure of the price or where go get one, it came with my compressor)
- 2" PVC cap - $0.52 - #23406 (Not available online, easy to find elsewhere)
- 1/4 mini ball valve - $7.96 - #221029
- Pressure Gauge - $7.94 - #221022
- 7/16th drill bit - $7.58 - #219842 (Not available online, and you can find them anywhere, probably cheaper too)
- 1/4 NPT Tap - $9.97 - #232530
- 2"x5' PVC Pipe - $3.97 - #23833 (Not online, but easy to find)
- Compressor air adapter - Depends on what kind of compressor you have. (It'll most likely be a 1/4th NPT thread)
You'll also need an old, empty propane tank. If you don't have one, you can get an oxygen tank from Lowes for about $5. Thats the cheapest kind of tank you'll find.

For tools, you'll need a grinder (Or a hack saw), some vice grips (Or a tap wrench), a cordless drill with a clutch, a 5/16th ratchet socket thing, and some misc Allen wrenches.

Comments

[dirjushunting]

Your techniques and use of tools is laughable and DANGEROUS. Messing with cylinders is ill-advised. Find a drill press next time. Next version how about a stock, sights and forestock? Its a decent try (for an 8th grader...)

[The Expert Noob]

Actually using a propane/oxygen or any metal tank that actually handle pressures much higher than 150 PSI are a hell of alot safer than PVC! PVC if over pressured shatters into billions of pieces and can embed itself into your body. A metal container would most likely rip at the weld seams before it would explode. ABS is bar far the best to use because it rips instead of blowing into millions of shreds. the only downside is its pressure rating is much lower than PVC. BTW SCH20 PVC is rated at 300psi and typical oxygen tanks are rated 500-1000 psi. My paint ball CO2 tank is constantly pressurized and unpressurized at 3000 psi! Oh yea and CO2 tanks get cold when they depressurize, WELL below freezing!!!! they can handle it well.(that being the pressurized tank side). Moving on to the barrel... the idea of the PVC pressure test cap you used was a bad idea... but the barrel is never pressurized enough to do harm... that said, if you can shove something down the barrel, the air that is about to escape will shove back out of the barrel with very little PSI, nothing to fret about. Ive got a Bachelor's of Science in Aerospace Engineering at Auburn University in Alabama and live in the Engineering Rocket City a.k.a Huntsville AL, don't EVEN Question me!

[mrtoast9000]

could you maybe use a fire extinguisher (cylinder) instead of a propane tank?

[The Expert Noob]

p.s. lay off on cvxdes, he's just making an instructable that for the most part is safe. although drilling into a propane tank is a bad idea because one spark = boom, follow watterppk's advice and drill underwater or use an air compressor and blow it out for a long time.

[irwinner]

propane tanks are 100% fuel environments unless theres something wrong with the valve. propane + No oxygen = NO explosion. if anything adding compressed air would be a very bad idea

[The Expert Noob]

I agree partially, but to create an explosion you need heat or a spark. decompressing air actually takes away heat. Besides i meant like using a blower nosle to blow out the propane tank after all the propane has been released and the propane tank valve has been removed, no compression at all.

[kibbler]

Not for all explosions, if that's what you were saying. I have overpressured a piece of PVC and it blew up, with no spark. But you are right about the latter.

[RMConstruction]

Technically, it didn't blow up. It shattered prom overpressurivation, and if there was a boom sound, it was escaping air.

[cvxdes]

(removed by author or community request)

[Brandon121233]

I would have to agree with dirjushunting on this, the build quality looks like something out of middle school. First of all modifying a propane tank to fill it with pressures it was never intended for is a very bad idea, I would pick a PVC tank for safety over that shoty tank any day of the week. Secondly that PVC end cap looks like an accident waiting to happen. Thirdly I feel really bad for what ever company your working for if your a machinist. Any person with half a mechanical brain knows that tapping a curved piece of 3/16th inch steel for a pressure fitting (and no Teflon tape on the list) is poor construction quality. No machinist would ever let a piece of crap like that ever been seen by any one. I personally would pick steel mesh reinforced PVC to any other kind of cannon material. My latest cannon has a 4inch by 3 foot tank with a 3inch 10 foot long barrel. I made it for under $40, which is cheaper than your and probably has triple the range and wont kill me one day.

[James (pseudo-geek)]

those things hold up to 150 psi normally, and are rated much higher. a disposable fire extinguisher is rated at 300 psi max. yes, I did see for myself, I checked the label. and a propane torch will hold far more pressure than a disposable fire extinguisher.

[Brandon121233]

yes but the keyword is "normally" as soon as one starts to tamper (IE drill holes, tap with hammers, and TAP) with that vessel, that rating no longer applies. I would not be too concerned with the tank bursting as much as I would be concerned about the pressure gauge or fill nozzle bursting out of the threads and seriously injuring someone.

[James (pseudo-geek)]

ah true. I didnt think about that.

[The Expert Noob]

when I built mine using a co2 tank i used the existing fill/release port, pulled that out and replaced it, all the fill and pressure gauges were on T fittings. No modifying to the tank structure at all.

[your_shadow92]

although i agree with that your fairly lucky not be injured while doing your project.... dirjushunting you should not be picking fights. cvxdes you should not be encouraging. and why cant we all just be friends? cvxdes good work.

[James (pseudo-geek)]

/agree.

[dirjushunting]

I do not make anything that is plastic. All of my work, paid and for recreational use is stainless steel or alminum.

[iBurn]

...then...why are you on this instructable...?

[dirjushunting]

I'll pass on the being specific and the elaboration. Clearly from your tone there is no benefit you'd be willing to recieve from a 30+ naval avation machinists mate, but... One nice thing though I feel compelled to put out there is your idea is good one.

[ilpug]

I think this is a good build. The fact that he used a propance cylinder is a bit questionable, but i find it to be safer than PVC, especially in a colder environment (remember, this is a SNOWBALL cannon.) Aslo, it doesent have to look amazing, it just has to work.

[mrafrica]

where would you get a tv that big?

[rock climber]

I have found that propane and oxygen tanks are 3/4 in threads. I use this instead of the 1/4in thing. By the way this cannon is great especially version 2.0 but i would recommend an oxygen tank.

[sora]

or an empty fire extinguisher

[rock climber]

ooooppps I was wrong, propane tanks do not have 3/4 threads. And no, instead of using the oxygen tank that I recomended use a footlong peice of 2 in galvanized steel with a cap on the end. I would also recomend using an "over under" design that includes a quick exhaust valve. This is how my newest cannon is designed and it shoots potatoes and tennisballs over 160 meters.

[Colonel88]

That's not looking to be safe. Propane tanks are dangerous, much MUCH safer to just make a container from some 3 inch pipe. And it is probably hard to open the valve, so you will jerk the gun and then your aim will be off.,

[red-king]

you can buy a snowball gun from hammacher schlemmer. http://www.hammacher.com/publish/76244.asp?promo=to_action

[ker-boom101]

This is just a thing i heard but appareantly when your tapping you cant use oil or lubricants as it puts pressure on both side of the threads top and bottom making it harder this also works with bolts

[bob the builder #1]

I would suggest not using pvc for a snowball cannon ,even if it is only the barrel, because when cold pvc gets very brittle and explodes easily.

[LED master22]

u got to make it good then look good!!!!!! or else its a bunch of PVC glued or whatever to some propane tank......life isnt bland dude, make it pretty!!!

[codongolev]

I made a potato cannon, and I spray painted it black with red accents over it. It's sweet.

[meritsetgo]

final nail in coffin for pvc in the cold. i was watching country fried videos on cmt and woudn't you know they had a potato gun being used in the cold, as i told my friend about pvc not lasting in the cold the video itself shows the camera going out of focus and people rushing to help the "shooter" the pvc gun cracked apart upon firing. i can't find the video yet, but the website at cmt had the episode info which i am posting here (tivo, youtube searches anyone???)http://www.cmt.com/pictures/country-fried-home-videos-rollin-your-own/1552865/2353396/photo.jhtml. remember this stuff is only fun as long as you play it safe. cheers.

[cvxdes]

I dont know how many times I have to say this... but the pvc is only in the BARREL. With this set up, it is impossible for the PVC to rupture. Simply impossible. There's no pressure on the PVC, there's nothing pushing on it. All the pressure pushes on the snowball, not the PVC. I've shot it off enough times and the barrel is still good.

[kibbler]

Well, not really. If you had a tight enough seal with the snowball, then there might be pressure, but what are the odds of that?

[meritsetgo]

ok, just to be abundantly clear, note i said "pvc in the cold" I am not necessarily against your gun or your instructable, matter of fact, your gun may never fail from the cold, however the issue here is that pvc does shatter in the cold, and if enough people make them out of pvc in the winter then it is bound to shatter, again may be not your gun in your location ever, but someone, somewhere else will potentially get hurt. in the cmt video i referenced before, the shattering happened upon firing and it was the barrel that broke apart, granted they were shooting a potato in the cold but you have to understand people are not thinking too much and just want to have fun. so please do not take this as an attack on you or your instructable, only as suggestion to make a fun instructable safer under all circumstances including weather!!!! cheers! I think the collective has come up with other alterntives to pvc in the cold so let's try them out. part of the fun is putting up your creation for review and suggestions to make it better. most projects here have had some tweaking done to them by rest of us and that's what makes this place great, we do care. Later

[cvxdes]

Ok, no offense taken.

[afartinthewind]

I can't believe he drilled a propane tank without purging it.

[Mr. Deeds]

Hmmmm... couldn't someone just take a perfectly good tennis ball mortar and only have to worry about snowball diameter? I know that it wouldn't go very far, but it would be quite a bit cheaper. I do, however, like this idea. Hurling snowballs at high velocities (for a snowball) sounds like it could fit itself into my budget... if we ever get snow long enough for that.

[blugyblug]

Listen to irwinner, seriously, hes they guy that made this crazy 25mm Pneumatic Sniper Rifle that could probably own urs... 0o

[sensoryhouse]

you guys are a bunch of morons, what do you think a potato canon is made out of. PVC.

[SilentTecro]

I agree with frollard. PVC is deathly weak in the cold and it could definitely shatter without warning.