Instructables

How to Make a Coaxial Air Cannon

Featured
video How to Make a Coaxial Air Cannon
This video shows how I make a compact 2" bore air cannon with a coaxial piston valve. To understand how these valves work examine the third animation in the following link:
http://www.spudfiles.com/forums/piston-valves-explained-visually-t8157.html
I also go into more detail of how these cannons function in a video I made many years ago, showing how to build a smaller version using these same principles:
http://youtu.be/9oARDyn4WwE

Warning: It is specifically against manufacturer recommendations to use PVC to contain pressurized air. This video is solely for education and entertainment purposes.

The parts used in this cannon are as follows:
(1) 3' length of 3" diameter pressure rated PVC pipe
(1) 3'2" length of 2" diameter pressure rated PVC pipe
(1) 1/2" PVC ball valve
(1) 1/2" x 2" long threaded PVC pipe nipple
(1) 1 1/2" to 1/2" threaded PVC reducer
(1) 3" to 1 1/2" PVC reducer
(1) 3" PVC coupling
(1) 3" female threaded adapter
(1) 3" male threaded adapter
(1) 3" to 2" PVC reducer
(4) 1" long self tapping screws
(1) brass air compressor tank valve
(2) 3" galvanized steel gas vent tee caps
(1) 3" rubber washer or sheet rubber
(1) 3" tank to bowl rubber gasket

Other supplies and tools needed:
PVC Primer & Cement
Epoxy
Super Glue
TFE Pipe Thread Paste
Coarse and fine Sandpaper
Bench Grinder or Metal Files
Drill & Bits
Bicycle Pump or Air Compressor

Thanks for watching!
chughes5 months ago
Have you considered combining the cannon with a pump like the "...High Volume Manual Vacuum Pump?" Like a Super Soaker, then you would not need to attach/detach a bicycle pump and it would make it a little more transportable.
If I was to use a sprinkler valve instead of the ball valve on the back which way should the flow ????
you would want the arrow on the flow valve to face away from the cannon and i would recommend a modified 3/4 inch sprinkler valve (if you don't know how to mod one there are plenty of videos on youtube) any other questions just ask me on my page. Hope this helps!
I was wondering if you can fire anything smaller than 2" or would you have to put an adapter on it?
dcord8 months ago
This is amazing, graet job! So, potatoes and golf balls. Has anyone tried any other types of ammo? Paint balls or BBs shotgun style for instance. I too would like to tinker with the higher pressures, and plan to use my portable 2 gallon pancake air compressor, but the bike pump is cool too. Thanks!
nelson17675 dcord7 months ago
For paintballs and BBs, you can use the discarding sabot principle adapted to cardboard and duck tape (which btw is my solution for basically everything). All you have to do is make a canister the diameter of the barrel, with one end open and the sides split in half (so that when it exits the barrel, the sides fold away from each other, creating drag and thus discarding the sabot from the paintballs/BBs.)

http://www.milsimlabs.com/ammo.htm
nelson176757 months ago
awesomee!
buskrat8 months ago
I found that with my mallow cannon I used thinner rubber and made the piston out of some liquid plastic and now it fires great 40 psi leaves a nice welt at 50-60 feet
buskrat10 months ago
I just recently tried the down size one to launch marshmellows (big kid mallow wars) and I cannot figure out the piston it won't seal to the barrel and when I get it to the pressure only holds for a few seconds do I need the piston to be a tighter fit of is my sealing surface on the end of the barrel the problem?
Randumb8310 months ago
Could I make a 1 or 1 1/2 inch barrel instead if so what would I have to change?
NightHawkInLight (author)  Randumb8310 months ago
Just the reducer in the front to bring it down to the smaller size.
Randumb8310 months ago
How much did this cost?
jimbob199611 months ago
I find that the best projectile for a 2 inch barrel is a golf ball. Works perfectly with my metric 50mm barrel
mudfish1 year ago
beautiful !!!...as soon as turkey season is over...
very well written ,most informative . can't wait to try this.
alahlou1 year ago
Hey! Great ible. I was just wondering the ballpark for how much this costs from scratch
Half1 year ago
Great air cannon. Just if other people were wondering you can use a simple bike valve instead of the one he has. It can hold a considerable amount of pressure (more or less 100 psi) and all you have to do is glue it on with sealant.
You forgot to list:

(1) 3" tank to bowl rubber gasket.

This is my next spud gun.

In the video you mention only pressurizing to 40psi. Have you tried higher? I regularly go to about 110psi with my sprinkler valve actuated spud launcher.
NightHawkInLight (author)  robertrunyon1 year ago
Thank you, I'll add it to the list. I do go to around 110, but I don't recommend it to people who may be working with PVC for the first time.
cryophile1 year ago
That's a great cannon! What should I do if I want to increase the power?
NightHawkInLight (author)  cryophile1 year ago
To increase the power, adapt the back of the cannon to accept a 3/4" threaded pipe nipple rather than 1/2", and use a sprinkler valve rather than the ball valve. Look up how to modify a sprinkler valve for air use and you'll be in business.
jimmyf1 year ago
Very professionally made ible. Thanks for sharing
Tachyon1 year ago
Nicely done. Thanks.
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!