There's nothing wrong with potato guns... we love sparking up Right Guard as much as the next geek. But compressed air, now that makes for a seriously fun cannon.
We've been asked several times about building spud guns on Systm. Whether you call 'em spud guns, potato cannons, combustible (or pneumatic) potato launchers... and whether you're shooting tubers, tennis balls or random bits and pieces found around the garage, they're fun. And easy to build.
We built a compressed air (or CO2!) powered cannon on this week's episode of Systm.
We chose pneumatic 'cause they're easier to load, faster to shoot, don't require an ignition systm (tho you can get into some serious mods for the sprinkler valves most folks use to control a cannon) and, frankly, figured building a tennis ball launcher would go over better with the wife than a Potato Mortar of Doom.
Plus, frankly, we're inspired by the cannons Joel Surprise has built at spudtech.com
BTW, if you're looking for a new career, is for sale, along with the spudtech.com URL, the tools to build rifled PVC spudgun barrels, and who knows what all else. The current owner, Joel Surprise, can no longer operate the Spudtech out of his home shop, and he's ready to move on. Bummer, since he's built some amazing cannons.
The heart of our tennis ball cannon is a 1 inch inline sprinkler valve that controls the air flow.
The barrel is 121 inches of 2.5 inch Schedule 40 PVC and the air tank is 6 inches of 3 inch Schedule 40 PVC... we had a second 24 x 2.5 inch barrel ready to go, along with a 12 inch x 3 inch tank, but operator error at the drill press (It rolled off) cracked it beyond repair.)
Using Schedule 40 or 80 PVC is critical. These types of pipe are pressure rated. If you don't see Schedule 40 or 80 and a pressure rating on a piece of pipe and the fittings you use to join them, -don't!!!- use it for this project. It could blow up! That would be bad.
Also, not waiting 24 hours after you glue the parts together is bad... the cement needs that long to set. (Did we mention don't blow stuff up?)
The C02 regulator we used to connect to our tank came from Lowes, it's their
Kobalt Portable Compressed CO2 Regulator... it uses regular paintball tanks, and you'll want to buy a few on the cheap to take with you. Or an air compressor. Our 20 oz tank ran out in less than 20 shots! (Fortunately, we had an air compressor we could use, to a 20oz tank is a -lot- more portable!)
If you're thinking you'd rather build a combustible potato cannon, head straight to Build Your Own Launcher at the Joel Surprise's most excellent Spudgun Technology Center. It's the best set of directions we've seen anywhere on building a basic potato gun.
Wish we'd known about Spudfiles Spudfiles
before we finished this project, they've got an excellent step by step on modding sprinkler valves for performance!
Got any links you think we should add in here? Email 'em to us: systm@revision3.com
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Posted by kevincollateral on 03/21/2008 at 12:32:41 pm in Systm
love the bouncing soulds shirt patrick! mad props
and keep up the good work
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Posted by lordbyron on 03/14/2008 at 05:27:14 pm in Systm
"
But for legal reasons they have to say it !
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Posted by xplorer on 03/11/2008 at 06:54:17 pm in Systm
"there should also be a warning...
NEVEr leave a cylinder CHARGED... Heat and TIMe can/will destroy the integrity of the cylinder.."
No doubt and for that fact not only does that apply to pneumatics but hydraulics as well.
When finished remove all pressure from the system!
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Posted by eca on 03/11/2008 at 06:21:21 pm in Systm
there should also be a warning...
NEVEr leave a cylinder CHARGED... Heat and TIMe can/will destroy the integrity of the cylinder..
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Posted by Technobob on 03/11/2008 at 04:27:15 pm in Systm
I use propane and I have been out a few times at 10 degrees with no issues. I build my cannons with the heavier SCH80 for SCH40 I don't think I would risk it at 10 degrees.
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Posted by eca on 03/11/2008 at 03:15:09 pm in Systm
Bob,
Also at 10 degrees C..
MOST propellants STAY liquid...NOT a good thing for the PVC, as it might tend to EAT the PVC.
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Posted by xplorer on 03/11/2008 at 03:14:42 pm in Systm
I love the episode, it looks like you guys had a blast making it.
Pat in super speed Benny Hill-O-vision was great!
Not to mention how giddy he gets when outside firing the thing!
But alas I do see one glaring issue. Whats with the constant repetition? Every time some point was made, a few minutes later in a different location we hear the same info again.
I love the content, but I feel the show could use a little trimming / more prep.
Just my $.02
Keep up the good work!
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Posted by Technobob on 03/11/2008 at 01:20:00 pm in Systm
I have been making spud guns for many years and I know all to well the dangers these things can cause. I was out with a few buds having some fun when it went all bad real fast. My friend thought it would be cool to fire his cannon from his shoulder like a bazooka. The cannon exploded taking out his eardrum and scaring his face forever. So never fire these things anywhere near your face it's best to keep them below you waist.
I'm just building a new cannon for this year as my old one is now a couple years old. I'm using a 5' X 4" air chamber with 2 3" elbows and a 2" brass air valve with blow gun mod a 6' X 2" barrel. All of my PVC parts are SCH80 so I can up the pressure to 200PSI and plus I'm all about safety now.
Another safety tip: PVC does not do well in the cold don't fire these if it's colder then 10 degrees Celsius
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Posted by Murphy1d on 03/11/2008 at 07:47:20 am in Systm
22 years ago I was using de-natured alcohol as the propellant. Is the Right Guard/Hairspray mix a better way?
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Posted by master1228 on 03/10/2008 at 11:15:05 pm in Systm
Watching the time lapsed setup of Patrick cutting and fitting all the PVC pieces in what looked like a garage towards the end of the show was great, it really made the show!
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