Well, if you want something bigger just scale it up! Multiply the barrel length and chamber length by 2 (Or a number of your choosing)!

1" caps fit in 1.5 with ~0.0295 clearance.
Sources:
<A HREF="http://www.spears.com/prod_dimensions_s ... f">Fitting dimensions (cap on 55th page)</A>
<A HREF="http://www.spudfiles.com/Other/pvc_pipe_info.php">Pipe Info</A>

The reason he rigged up the double valve system was because the 2" valve most likely has a larger equilization hole and so if you activated it with a valve that has a low flow the pilot volume would not empty quickly enough to overcome the air flowing from the chamber. This would mean the valve ...

I've seen some so I'm sure that you can. I think that Saladtosser has some on his site. <A HREF="http://www.freewebtown.com/crazylilproj ... d1.htm">In the second section</A>

Found it!
<A HREF="http://www.spears.com/prod_dimensions_s ... pdf">linky </a>

Is there a site that has the dimesions of different fittings on it? I spent about thirty minutes searching for one on Google (but that doesn't count for much 'cause I don't have Google searching skills ). Maybe one of you guys could help me find one.

From your drawing, I don't think that anything will happen, the piston has an equal surface area on the two opposite sides that are being pushed on by the air, so the forces will cancel out. At least thats what I can see from your drawing, assuming that whereever two pieces touch it is a perfect seal.

A flyback is a transformer used to step up the voltage to operate the CRT, Cathode Ray Tube, (explanation: http://home.howstuffworks.com/tv3.htm .
I would use a camera flash ignition by removing the flash bulb thing and connecting the wires that went to the flash to the ignition screws in your ...

I don't think he uses methonal, instead he just presses the trigger, creating the spark and igniting the fuel. Then the air from the bottle vents the chamber as the alcohol(sp) evaporatesand until there it is the right ratio to combust, again.

Rambo: That is my understanding, if I got anything ...

[rant]Look in the linkin BLB's post! People put links in thier posts for a reason![/rant]

potato mass in calculated like this: http://www.spudfiles.com/forums/viewtop ... tato+mass&

That and they have a faster actuation speed than a normal piston, Joel compares it to a diaphragm valve.

Good ideas!
@Pimpman; I looked at smoke machines in general, seems that they use "smoke juice" which is then put into a chamber with a metal plate that heats it until it vaporizes creating pressure that forces the thick white fog into the room. It would work, if the play was organized differently ...

See that's the problem, I think the principal is really freaked about fire or something and won't let there be any on the stage. That's why we built a pneumatic one instead of a combustion. Only problem is that with my friends design there is no muzzle flash and I have concerns about the flour ...

My friend, a fellow spudgunner, is building a "cannon" for a play. He decided to use a pneumatic burst disk replica of a carronade, a miniature(sp) cannon. It is built with a three inch chamber and a sprinkler valve connecting it to a three inch burst disk. Then he is going to construct an ABS ...

Those people are disgusting (the criminals)! Saladtosser, cell core would just look like a sort of web of PVC I guess.