Using about 30 dollars worth of PVC you can build a compressed air cannon that will launch almost anything put in its barrel at high speeds
Step 1: Gather the PVC
All the supplies for this PVC cannon can be found at Home Depot
The materials you need are
• about 4-5 feet of 3/4 inch diameter PVC pipe
• two 3/4 inch diameter non threaded ball valves
• two 3/4 -2 inch end caps
• two 2 inch end caps
• I don't know what they are called but the bulky looking air tank in the pictures
• PVC primer and cement
Step 2: Dry Fit the Parts
Dry fit all the parts together. I attached a drawing of all the parts in there place. The air tanks are composed of three parts a 3/4-2 end cap ( it looks like an avg end cap but it has a hole the size of a 3/4 PVC pipe in it) a tube which came with 2 rubber rings and 2 threaded end things to keep the end caps on, and a 2inch end cap.
Step 3: Prime and Glue the Pieces Together
The next step of making this air cannon after dry fitting everything is to attach everything using primer and PVC cement. Be carefully when glueing the pipe into the ball valves, if any cement gets into the valve it may stick and ruin your cannon. No cement needs to be used to create the air tanks as the end caps should be able to be screwed into the tanks main tube. However the whole air tank will have to be glued to the rest of the gun. The barrel is not glues to the rest of the air cannon
Step 4: The Air Tank
In the one of the air tanks a bike tires inflator nozzle thing has to be put in so the air tanks can be pressurized. To do this first take apart the air tank by unscrewing the end caps. Next drill a hole a tiny bit smaller than the diameter of the bike inflation nozzle in the solid 2in end cap. This will almost definitely leak air. To prevent this from happening you can wrap the bikes tube nozzle in Mylar tape or epoxy the nozzle into place
Step 5: Test
To test your cannon wait until your PVC cement has dried, if it is not dried don't use it this could be extremely dangerous. Next close the ball valve closest to the barrel so no air can escape. The highest I have ever tested my air cannon to was 75 psi. I do not recommend going much higher as I have not tested it and I don't know the pressure limit on the air tanks. I have found the best things to shoot are AA batteries with a wad of paper to seal the barrel . I attached a larger PVC pipe to the end of the barrel so I could shoot larger items like airsoft gun weights salvaged from a broken one.
Step 6: Disclaimer and Troubleshooting
I am in no way responsible for any harm or damage caused by this instruct able or any of the knowledge contained within. Build and use this cannon at your own risk.
If your air tank leaks spread some petroleum jelly on the rubber rings in the tank
If any you have any questions or concerns please feel free to leave comments and I will help you to the best of my ability, sorry about any typos or confusing pictures/ instructions