Help with large 3" cannon

[TG75]

How high of pressures? Would an average air compressor be fine?

[RBurke83]

My compressor only goes to 90psi, I feel comfortable with malleable steel(sometimes called blackpipe) at prob 300 psi. That stuff is cheap at homedepot, and usually prethreaded. I was actually kinda sore after putting a blackpipe spring powered ball valve gun together a while ago - you really gotta put your back into it while tightening.

[TG75]

Ok, so far I am looking at having a 5' long 3" PVC barrel and a 5' long 4" galvanized Steel chamber. What kind of power and range should I expect out of that?

[mobile chernobyl]

Did someone say 3" barreled cannon?

[youtube][/youtube]

Sorry had to toot my own horn

[TG75]

That is the exact design I have been looking for.
does anyone know what valve they had on it?

[RBurke83]

Probably piston, its hard to see what that pull cord is attached to, so it could be a spool valve but i doubt it.

[Technician1002]

It's a piston.

[mobile chernobyl]

I originally built it with a 1" manually piloted sprinkler valve, when that failed I just through a spring loaded 1" ball valve with a string on it. It's probably fired close to 1000 shots by now and will most likely feature a viking funeral this summer due to so many thermal cyclings and UV exposure (it's been stored outside in NE USA for the last 3 years lol).

It was a fun gun, but PVC has it's limitations - mostly with regards to safety. My next 3" cannon will feature similar dimensions but constructed of heavy steel, featuring a road worthy trailer and gas powered compressor on board and designed for a 10X hybrid mixture

[RBurke83]

The first mac and beef shot was my favorite.