In this instructable I will show you how to make a PVC air cannon for around 40 bucks.

Step 1: Materials

-2 feet of 3 in. PVC pipe
- 3 in. x 3 in. x 1 1/2 in. PVC tee
-2 3 in. end caps
-1 in. threaded ball valve
-2 1/2 feet of 1 in. PVC pipe
- replacement tire air valve
-PVC cement
-PVC primer
-duct tape (optional)
-thread tape
-2 1 in. threaded adapters
-5 minute epoxy
-1 1/2 in. x 1 in. Bushing

Step 2: Cutting and Drilling

First cut the 2 feet of 3 inch PVC in half so you have two 1 foot pieces. Then cut the 1 inch PVC so you have a 6 inch piece and a 2 foot piece. Drill a 3/8 inch hole in one of the end caps and epoxy the valve into the hole you made.

Step 3: Gluing

Glue the 1 inch threaded adapters on to the 1 inch pieces of PVC. Now glue the 6 inch piece of 1 inch PVC to the 1 1/2 inch by 1 inch bushing. Glue the 3 inch by 3 inch by 1 1/2 inch tee connector onto the 1 1/2 inch x 1 inch slip bushing. Glue the 3 inch PVC to the 3 inch by 3 inch by 1 1/2 tee connector. Lastly glue the end caps on to the 3 inch PVC. See the diagram above for help. Warning: be sure to let the epoxy set and make sure that it will hold so the valve won't be stuck inside the chamber.

Step 4: Wait

Wait at least 3 hours tor the PVC glue to dry. Now you can wrap duct tape around it for extra strength. Thread the 2 foot pice of pvc with the ball valve and the main chamber to the ball valve.

Step 5: Launch!

Put the thread tape around the threads and then your ready to launch. To launch your cannon, Pressurize the cannon to about 30 PSI. Then, put a piece of cloth in the barrel for the wadding and push it down until you reach the valve. lastly put a projectile in it. (I like to use chalk because it fits nicely into the barrel.) When you're ready, turn the valve and fire! Your projectile will fly through air. This cannon's barrel is interchangeable which allows you to shoot different size projectiles. I am not responsible for injuries.

Step 6: Problems

If you think your cannon is leaking, squirt soapy water over the seams with a spray bottle. If you see bubbles over the seams, you can use some epoxy to cover the leaks.