Air cannons. Fun for the whole family. Shoots anything, really. Bottles of water for the kids, bottles of liquor for dad, kitchen utensils for mom, food for the dog, the dog (Kidding), stuffed animals for the little tykes..... Good fun. You can also shoot nets, grappling hooks, bricks, smaller air cannons, dumpsters (if they'll fit in the barrel), your mother's china, lit fireworks, and politicians. They are mainly used to shoot projectiles like balls (tennis or golf balls), potatoes, and my personal favorite-water balloons (filled with the liquid of your choice!). The whole point is this-you NEED one of these babies. And you need it NOW. Of course, I'm aware that this isn't the first air cannon instructable on here, and it won't be the last. But I hope that it's helpful, inspiring, and if nothing else I hope it's at least humorous.
Before we begin, there is a point I would like to stress- and that is Stupid hurts. You are building an air cannon (this could be used as a weapon). Because this cannon will belong to you, and it is your cannon, if you decide to do anything..................well, stupid with it, it's also your stupid. So it is your cannon, your responsibility, and anything you do with this thing is your consequence! That being said, END DISCLAIMER, BEGIN INSTRUCTABLE!!!!!!!!
In case you don't know how these amazing devices work, well obviously they use air (DUH-air cannon). Air is pumped and compressed into a chamber on one end of the gun, and on the other the ammunition is stuffed into the barrel. The barrel is connected to the pressure chamber via a ball valve or an electric solenoid valve. The valve lets the all the compressed air flow from the pressure chamber to the barrel, pushing the projectile out of the barrel and into the next county.
Step 1: Scavenge, Scrounge, and Look Around.....
What's wrong? The parts for the cannon aren't just going to appear in front of you! You have to find them (Buying them is optional). You're going to need a lot of things for your cannon (trust me, I built one). Here's the stuff I used to build the cannon shown here, and most of these parts are easily found at your hardware store, or in your annoying neighbor's garage while they're in Florida for their spring break (again, kidding).
-3" Pressure-rated PVC pipe (Never use non-pressure rated pipe for projects that use high pressure air. The results could end with exploding pressure chambers, shrapnel, and a trip to your local emergency room or cemetery. You'll need a good length for the barrel and another for the pressure chamber)
-a 3" end cap (Pressure-rated)
-2 reducers (3" to the size of your bushings)
-Ball valve or solenoid valve of the size or your choice (Bigger is better, I used a ball lever valve on this one)
-Bushings for connecting the reducers to the nipples for the valve (female thread, male slip fit)
-Pipe nipples for the ends of the valve
-Drill and drill bits (needed for making the holes in the pressure chamber)
-Channel lock pliers (used for tightening)
-Thread Tap (threads the hole for pressure gauge)
-Circular saw (for squaring off the ends of the pipe, or for cutting lengths of pipe in general)
-Drill press (optional, used it to make nice straight holes)
Other things you'll need:
-PVC cement and primer
-Schroeder valve (aka- "Tire valve") (with a screw cap)
-Teflon tape for sealing threads