What is an air cannon? For those who don't know, It's a gun that shoots stuff by using the power of compressed air. You pump up the gun, flip the release valve, and it shoots whatever you put in it out at high speed. For ammo you can put anything down the barrel. if you choose to use smaller ammo that doesn't fit down the barrel, just attach a smaller barrel.

This build is relatively simple, and doesn't require much experience, so anyone can do it.

I made mine out of galvanized steel pipe, but it cost $50. I don't recommend using black steel pipe, because it is rusty on the inside, and has an odor. If you want to adapt this design to use PVC pipe, it should cost less. If you want to use an air compressor, instead of a bike pump, it should be easier to pressurize (obviously).

Step 1: What Do You Need?

You can get everything at your local hardware store.

Here is what you need:
- 2: 1/2" x 1" galvanized steel nipples
- 2: 1/2" brass ball valves
- 1: 1/2" x 3' galvanized steel nipple
- 2: 1/2" to 3/4" galvanized steel bushing
- 2: 3/4" to 1 1/4" galvanized steel bushings
- 2: 1 1/4" galvanized steel couplers
- 1: 1 1/4" x 6" galvanized steel nipple
- 1: 1/2" x 1/4" brass bushing
- 1: 1/4", NFTP, industrial plug (male)
- hot glue
- bike pump or air compressor

Step 2: Some Assembley Required

below. Aftertures below are pretty self-explanatory. Assemble it as you see below.

After you have done that, put hot glue around every connection EXCEPT the 1/2" x 3' nipple. That way, your connections are air tight (without the glue, all the air escapes, and you can't get any pressure).

Step 3: Check for Leaks

Close the bottom valve and open the top valve. Pour some water down the barrel. Attach the pump or compressor. Close the top valve and open the bottom valve. Look for bubbles. Apply hot glue to the leaks.

Step 4: Fire!

fire. Hereitem you wish to fire into the barrel. Push it down until it hits the bottom with some kind of rod. Close the top valve. For ammunition, I recommend using nerf bullets, markers, blue berries (they go splat), or anything else that fits down the barrel. Attach the pump or compressor. Pressurize it to at least 100 PSI. If you would like to detach the pump or compressor, close the bottom valve. Open the top valve to fire.

Click on the video to see the air cannon shooting a nerf bullet at about 100PSI.