This cannon is an excellent starting point for you amateurs out there who are just starting to take this wonderful hobby.  This gun is extremely easy to build and understand.  This gun is very similar to the first spud gun I built (petard).  At first I heard that pneumatic guns were more powerful than combustion.  The combustion cannon, being the first one I had ever built, packed a pretty good punch and was really loud.  Eventually I caught on to the fact the "pneumaticizing" a gun makes it extremely more powerful.  To build this gun you need an air supply. Bike pumps are fine, but you'll find that it gets much harder to pump after about 30 PSI. 

I recommend that you copy the following into a Microsoft Word Document or something of that nature and print it out.  You can't be dialing up the internet service every 20 minutes to see what the next step is can you?  This is simply for your convenience.  Right then, to business...

You will need the following materials which should be easily obtainable at most nationwide popular hardware stores.  Do not hesitate to contact me if any of these devices are unobtainable or you're not sure about the quality of something.

• 3" end cap

• 3" coupling

• approx. 24". of 3" dia. PVC

• 3" -1 1/2" flat reduction bushing (s x s)

• (2) 1 1/2" - 3/4" reduction bushing (s x s)

•  3/4" tee (s x s x s)

• 3/4" end cap

• 1/2"-3/4" reducing elbow ( t x s)

• Several short pieces of 3/4" PVC

• (2) 1/2" short pipe nipples

• 1/2" ball valve (t x t)

• custom barrel 

• Tire Valve

• Pressure Gauge

• Hacksaw
• PVC glue and purple primer (required)
• Various drill bits
• Electric Drill
• Teflon Tape
• Mole Grips 

After collecting all the previous assemble each of the pieces in the manner as follows.
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         3" End Cap                 3" coupling                 3"-1 1/2"               1 1/2"-3/4"       3" Dia. PVC
                                                                             Flat Reducer          Flat Reducer

*Congratulations. Upon completing thus so far you have nearly finished the air chamber.  DO NOT glue the end cap on yet!  Read on to learn about the air insertion and moniterization assembly.

                                                                                                                        Air Gauge                               Tire Valve (only need one)   

Next you will need to drill two small holes, one in each end cap, slightly smaller than the diameter of the neck of both the pressure gauge and the tire valve.  Then screw them into the caps.  The tire valve is the most difficult to get through.  You will know when it is sealed. Use the mole grips to pull it through.  When finished they should look like this...   

Now then.  To the release assembly.  On all threads you should wrap several layers of Teflon Tape.

 1/2" Short                 1/2" Ball Valve (t x t)         Teflon Tape (Needed to seal all threads)
Pipe Nipple

+=
3/4" Tee                           3/4"-1/2" Reducing Elbow (s x t)

Now put all the components into this order and carefully prime and glue all connections. Let the whole assembly cure over night. Remember.  Screw everything together that needs to be screwed before gluing or else you'll have to start again from scratch. Now you're set! Simply add a custom sized barrel via a 1/2" female adapter for whatever sized projectile you desire and there you go!

1/2" PVC Barrel----paint ball sized

Remember that you can make any sized barrel you want so long as it has a 1/2" female thread.

The MAX YOU SHOULD EVER PRESSURIZE THIS GUN IS 60 PSI! Give it a couple of dry low pressure test before loading it 

Simply attach an air hose, pump it up to about half pressure and release the valve.  Now in utter amazement go and try it again adding a little more pressure and maybe a projectile.
Upon Completion of this project drop me an e-mail and I'll give you some info. on where to go next!