This Cannon is my 2nd to instructables but the very best out of my other cannons. (in lethality, distance, power, and odd-looking. The also has the best advantage of being 1/2 barrel diameter, meaning it fires Paper darts, NERF DARTS, double A batteries, firecrackers of the right size, airsoft BB's, and anything else that you can find.

it's a lot bigger than it appears

BE CAREFUL!
the double A batteries are not to be shot at anyone
.
so lower the pressure if you are going to shoot it at someone. and not at their face

Step 1: Materials

Materials:

1-1 inch PVC pipe (8 feet standard I believe)
2-1 inch end caps
1- tire replacement valve (auto parts store)
2- 1 inch, 45 degree angled elbows
1- 1 inch T valve
1- 1 inch elbow
1- 1 inch non threaded/threaded 1/2 inch adapter (elbow)
1- 1/2 inch threaded pipe (6-8 inches, depending on preference)
1- 1/2 inch threaded pipe (14 inches long, or how ever long you need your barrel
1- 1/2 inch threaded on both sides ball and socket valve

Other parts:
PVC Cement
PVC Primer
Hacksaw
Superglue
Silicone (optional for leaks)
Bike Pump W/ A GAUGE! (a compressor just doesn't work very well)
Tape Measure
Pen ( To mark cuts)
Drill

Step 2: Measure Your Piping

First, measure the length from the top of your shoulder to where you would like to hold and fire the cannon.

Next, cut a piece of the 1 Inch piping that long.

A)Cut 1piece of the 1 inch PVC about 2 inches, just enough so it connects the vertical elbow to the T valve.

B)Measure how far you want the first compression chamber to connect to the T valve.

C) Take the same length PVC (B) and cut one the same (or a little more) length to connect the top compression chamber.

Step 3: Compression Chambers

'The chambers are designed to gather as much air as they can to build up pressure and release it through the valve all at the same time. The wider and longer the chamber, the more force it releases and can contain.'

First, Gather the last length of PVC you have (hopefully it's in one long pipe) and cut 2 equal pieces using all of the 1 inch piping. (These are the Chambers.)

Step 4: Adding the Tire Valve

The tire valve needs to be added to the end of one of the chambers.

Find one of your 1 inch end caps and Drill a hole big enough for the tire valve to stick out but not enough that it slips right through.

Push the tire valve through the hole and make sure it fits snuggly.

Now, super-glue the tire valve on the outside. ( the spot where it sticks out, the stem.)

Wait a good while for it to dry and make sure you cover all of the holes to avoid leaking.

Step 5: Glue!

now you need to add the primer and cement, at about the same time.

prime the inside of the elbows, T valve, and end caps. ( you might need to add the primer and cement to the pipe instead of the end cap with the tire valve so it will cover the whole inside of the cap.)

don't prime/cement the threaded ends or valves

Step 6: Thread!

Add the 6-8 inch threaded 1/2 inch pipe to the elbow adapter

Thread the barrel 1/2 inch pipe

Step 7: FIRE!

Wait a good day or so for everything to dry.

take to a desolate area (or your driveway) and fire away from people with the heavy stuff like the batteries.

make sure if you must fire at someone (which you will) then keep the pressure low (20-35 psi)
40 psi stings quite a bit with a nerf dart

WEAR EYE PROTECTION, i cannot stress this enough.

Be safe, have fun, and my next project is a tri-barrel airsoft shotgun so look for that one as well

~pbpenguin5