Hey everyone! This is my latest air cannon which is made from a retired fire extinguisher. It is by far the most powerful of all my homemade cannons. This system is capable of holding pressures up to 500 psi! I've only put 160 psi in it so far and don't plan to put much more than that in the future. I put a video on my channel here. Check it out for a more detailed tutorial and to see some really cool slow motion of it destroying things.
Step 1: Parts List
(1) Fire extinguisher
(several) 1" and 3/4" black iron pipe and fittings
(1) threaded Shrader valve
(1) 1" ball valve
(several) PVC barrel sizes and adapters
Step 2: Building It.
First I emptied the powder out of the inside of the extinguisher. Then I began fitting the pipe together. I was missing a fitting and decided to weld the gap which turned out really nice. I used TFE paste which is rated for 3,000 psi to see the threads. I used JB Weld to connect the black pipe to the fire extinguisher. This is super strong stuff and shouldn't have a problem holding back the pressure.
Step 3: Finish
All in all, it was super fun to build and a lot of fun to shoot. Hope you enjoyed this instructable. Again feel free to check out my video on making this.
Disclaimer: If you build and/or operate, you do so at your own risk.