Well, I did a test at 80 psi on my pick nick table and it only slid back about two feet. The truss is welded steel and weighs at least a hundred pounds. I decided to just fire it(from a safe distance) and see how much it moved and if restraint was neccecary. It dosen't seem to move much at all, all ...

No, you are not deceived. The truss is 1ftx2ftx16ft. It is two 8ft sections that bolt together. The tank is two 7ft sections of 4" pipe that join with a union, and the barrel is one 15' piece of 2". I can get all the pipe parts in and on my car. I moved the truss with a freind's truck. It is all pne...

Here is the cannon mostly done. I will get the few photos of the build I have and some explanations up sometime soon.

Yeah, I am going to have to look into doing more exact testing of performance. I am sort of new to the whole thing, this is my first cannon. I ended up with a fifteen foot barrel, as that was the longest I figured I could strap on top of the car. The idea being the cannon would be semi portable. I w...

Hey everyone, I have assembled the cannon and tested successfully up to 80 psi. I think it would be best to take it out of town for higher pressure tests, so I am not sure when I will do that. I also need to make a better piston I think for the higher pressure tests. I will get some pictures up in t...

Hey, just want to let you all know I have not abandoned this project. However some of the fittings have not yet arrived and I starting college so it may be a bit before I get it done. It will happen though, I have already invested $400 in parts. I was expecting to have the fittings sooner so I could...

That's a good idea. I will already have extra pipe since they only sell 20' sections. I think I will build this one first and see how it does, that way I can make design revisions if there are any obvious problems. Although assuming it does work at 300 psi, testing to failure might be difficult beca...

Yes I am definitely aware it may turn out to be more grenade than cannon. I am going to pressurize and fire it from at least a hundred feet to the side so that I am out of range of shrapnel, and the piston if it decides to take flight. Even if I get only a few shots, I will have built a large, mediu...

Certainly, the pipe should be here by the end of next week, so that is when I plan to start the build. In the mean time I am working on setting up the big hermetic compressor, I'll post some pics of that as I think it could be useful to others.

That sounds good to me. I have to wait for my pipe and fittings. Getting it from the local supplier, but they have to order it in. It does give me plenty of planning time.

Yeah, I know. I am always torn between is this too simple to work, or is it more complex than necessary with projects. My first plan was what you suggested, qev with a long airline. But all the ones I found were rated 150 psi, I guess they would probably work for 300.

I am not entirely sure, it depends how I pilot the piston valve which I still need to figure out. Was considering a ball valve with a spring as the pilot, but I am not sure if it would open fast enough for the most power. I could then have a rope tied to a pin, or even a small air cylinder to pull o...

Well the sch 80 pvc is rated 300 psi with glued joints only at 72 degrees Fahrenheit. But no, I am not sure it will handle the pressure which is why I am going to fill and fire it remotely.

Hello, I am working on building a relatively powerful pneumatic. I am using all sch 80 PVC for construction With a 2" barrel and 4" for the chamber. it will have a piston valve, and should be good for 300 psi max depending on temperature. I do intend to pressurize, and fire it remotely due to the pr...