SpudFiles

Ok so tonight I was talking with my dad about building my next cannon and I said I needed some sch 40 PVC which is expensive because the only close supplier only sells 10 ft lengths so he said my uncle might be able to get the steel pipe I could use for my cannon. Now this isnt set in stone because I am unaware of any specs about the pipe. But my cannon is going to be the same style as joels tornado launcher only smaller and maybe a bit different.

I am new to pneumatics so what kind of valve should I use? I have been looking into barrel sealing pistons, sprinkler valves, solenoids, etc. As for controls I am hoping to get a box off of gort sometime since its cheaper for him to make it then for me to make it.

Dont go with solenoids unless you can afford large diameter ones. I would go with sprinkler or piston.

Well if you are going to make one that largo or even close you are going to be spending hundreds if not thousands of dollars where as pvc is cheaper, much lighter and easy to work with

Yes that is true but as I said the cannon will be smaller and I think I forgot to mention the steel pipe is free.

what about the fittings they cost more than pipe

That's not really true with steel pipe, spudstuff.

Anyway, I'd sugest going with a triggered burstdisk.
Very high flow for pretty low prices, and is easy to build for high pressure applications.