Picture of Colossal Cannon: Building a behemoth piston-valved pneumatic
full cannon1.jpg

So you have a decent sized vacant lot of land (be it farm country, woods, tundra, ice shelf) and you think to yourself, "Hmm...I wonder just how far I can hurl stuff, maybe even into the next county." Or maybe you just like the idea of kinetic energies ten times that of a 50 cal bullet shot out of a sniper rifle. Or maybe you want to get into Punkin' Chunkin'. Well, my friends, you just might want a piston-valve pneumatic cannon.

It'll sure beat the pants out of your neighbor's ball valve pneumatic or hairspray combustion cannon.

Update 2014 - We were young and stupid when my friend and I first built this cannon. We made a lot of mistakes and a lot of safety oversights. I highly suggest reading up on modern potato cannon theory and design before delving into a project of this magnitude. Use your head!

Videos of the recent 2in valve:

Three test shots at 40psi, two with paper towel, the last one with a whiffle ball bat. We were gonna move on to damage shots, but it got dark. I should have damage vids up today or tomorrow.

Videos of the old Mk IV 3in valve:

Preparing for launch, I couldn't find the rocket. So I put in a can of lemonade instead. "There's the rocket!" refers to my sudden realization that the rocket was in the barrel the whole time. Rocket, lemonade, and wadding all shot out over 120 m.

My cannon has a record distance of 1900 feet (using Google Earth along with terrain mapping - it happened to land right between two distinct knolls that I could see from GE). That was a 70 psi shot with a 2.5in x 20ft barrel that was so long it needed it's own suspension system.

I have a video of that shot somewhere but I have it find it I'll post it as soon as I do. That was also the shot that broke the cleanout cap.

During the testing phases, the cannon was barely charged halfway, so I could get away with plugging my ears. I make sure to grab hearing protection for anything 65+ psi.

For these two shots we had an audience.

They were thoroughly impressed:

This shot, something caused the piston not to actuate, and we had a dud. They weren't as impressed :-P:

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HansB31 month ago
ive seen punkin chunkin with high pressure... how about trying a vacuum cannon... could you hit the magic mile with that?
nanosec124 years ago
This is a beautiful thing...............just beautiful..........

5 of 5
i might use steel pipe for my 4" val.much better under pressure.
caspar975 years ago
I don't understand where everything goes. I understand how they work and the concept, but could you please label the "bulkhead". I am building one myself and most likely will use this design.
DeusXMachina (author)  caspar975 years ago
The bulkhead is the part that connects the front side of the valve to the barrel. I haven't really worked on this project in a long time, and there are parts of it that need to be re-engineered, and I can't remember right now if the whole design is optimized. I would go to www.spudfiles.com and look up some designs and get a feel for valve design.
Hey, thanks a ton! I think I've got the jist of it, but I might have some more questions when I start to build it. (My partner is away for a couple of months.)
caspar975 years ago
is that valve 2in???
DeusXMachina (author)  caspar975 years ago
Yeah, that's the two inch valve. Sorry, I really haven't touched this project in a while, it would take me a while to get everything back up to speed. I would go to www.spudfiles.com and read up on the general mechanics of piston valves if you are unsure - they are rather tricky to make.
caspar975 years ago
What did you use as your rocket, and or how did you build it? (not that it would matter to me, since I would be firing it out into the water, but just to settle my curiousity)
DeusXMachina (author)  caspar975 years ago
The rocket was made out of PVC.
caspar975 years ago
Could you please add pictures here. That would be very helpful. I'm lost :(
 This looks really cool, are you a member on www.spudfiles.com, the only problem I see is that most of your parts are DWV,  your piston looks great, my piston on my golfball gun was just a coupler
DeusXMachina (author)  imthatguy11255 years ago
Yeah, I am, and yeah, I know. XD. That's part of the reason the valve exploded.
 Whats your username, arte you still active
DeusXMachina (author)  imthatguy11255 years ago
I haven't been on there in years, but I believe it is deusxmachina.
 You should return, theres a ton of new ideas floating around you probably missed
DeusXMachina (author)  imthatguy11255 years ago
I might. I'm just super busy a lot of the time. But thanks for the tip! :)
 No Problem, Im clemsonguy1125 there to by the way
hollowpoint5 years ago
where you able to get a 4in rubber O-ring at the store or did you have to order it online also who much did it cost and under what section in the store would it be found in? (plumbing, piping, exc, exc...)
DeusXMachina (author)  hollowpoint5 years ago
Hmmm....I actually don't remember. It might have been custom-made, there are make-your-own O-ring kits that basically give you a piece of rubber that you cut to size and glue together. You can also get them online, try McMaster-Carr.
It would be pretty much impossible to build a pumpkin-capable canon out of PVC.....Well, it is possible but either the pumpkin wouldn't move or the whole thing would explode.
tjk946 years ago
Suggestion: 1 Find a tree 2 Point this straight at it 3 Launch a fire poker at it
Bridel5686 years ago
how far will it shoot a bottle?
"Three 2"x1/4" steel nipples" ROFL, he said steel nipples! great instructable btw
It's called nipples.
ye i know (i laugh at 'nuts' occasionaly aswell) haha
TVKing6 years ago
How destructive is this to the projectile? I have a (slightly larger than) GI Joe type of Radio Controlled parachutest and 800 acres of field. Think load fire fly back to base, do over...
TVKing TVKing6 years ago
Radio Range over 1500 feet. Skydiver weighs a touch over 3 pounds ready to fly. I have not tried to see what size barrel would be needed, maybe a 3 inch. i would think electronics would hold up okay everything is enclosed inside the resin skydiver body.
DeusXMachina (author)  TVKing6 years ago
Depends on how good your electronics are. As long as they're decently hardy it should survive just fine. However, if your parachute didn't deploy, well, you're screwed. Also, take note of your radio range.
sweet! affordable heavy artillary! time to bombard the enemy tank collum(how accurate is this thing)
DeusXMachina (author)  themasterpyro7 years ago
Not terribly, although with finned projectiles you can see on the map that they all landed pretty much in a straight line. My friend jokes about having a contingency plan which consists of shooting black powder chargers with a safety fuse, just for the nice aerial blast. I told him sure thing as soon as terrorists invade Upstate New York. I'm dying to get footage of soda cans shot at 3/4" plywood, but it has been raining all weekend.
why stop there?put a WHOLE LOTA little steel balls or somthing, a giant shotgun. and then a large steel cone get the idea?
Redneck Deer Hunting.......
what psi can you pump it up to?
DeusXMachina (author)  - creative name -7 years ago
The highest we have taken it up to is 90 PSI. The maximum theoretical pressure it can handle is 125 PSI but that prospect is quite frightening. Hopefully before the cold sets in we will get to bring it up to that high and remote fire from 100 ft away.
Upstate New York you say? war time!!!! Crap, my wallet is almost empty....
even if not very accurate still god for area bombardment and area denial
Get damage footage! It looks impressive, but seeing the projectiles hitting stuff really sells it.
e13377 years ago
Not to bring shame on you but you used Dwv fittings such at the wye and one of the bushings. Dwv = not pressure rated = Shrapnel.
DeusXMachina (author)  e13377 years ago
Uhh, duh? Did you read the instructable? The whole reason the 3in valve failed is because it was DWV. And DWV does work for pressure as long as it has a pressure rating on it. Most of my pipe says DWV ###PSI.
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