Help with large 3" cannon

TG75 · Sun Mar 31, 2013 12:43 pm

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

RBurke83 · Sun Mar 31, 2013 1:58 pm

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 · Sun Mar 31, 2013 10:02 pm

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 · Mon Apr 01, 2013 8:13 pm

Did someone say 3" barreled cannon?

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Sorry had to toot my own horn

TG75 · Mon Apr 01, 2013 9:25 pm

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

RBurke83 · Mon Apr 01, 2013 10:49 pm

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 · Tue Apr 02, 2013 2:43 am

It's a piston.

mobile chernobyl · Tue Apr 02, 2013 6:38 pm

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 · Tue Apr 02, 2013 6:46 pm

The first mac and beef shot was my favorite.