SpudFiles

I recently built a pneumatic cannon using the plans on PVC Ballistics with minor modifications to the placement of the solenoid valve, and I also used 1.5" rifled PVC for the barrel. One of my good friends helped me pay for it and would have helped me build it, but pretty much all there was to do was cement some pipe and fittings together. However, he doesn't understand how the entire thing works. He took it to a pick up football game some of my other friends were having (and I'm not interested in football), and he decided to take it and show it off. I guess he was trying to do as I did when he loaded it, I think he tried to open the bleed valve, but messed with the large center valve and it didn't fire. After this, he called me and asked me how to fire it (WITHOUT telling me it had misfired before) and I told him to call back if there were any problems. He didn't call back, but it misfired AGAIN. Then, we (both of us) were at church and had an hour of downtime with a couple of friends and decided to fire it. At this point I still don't know that it had misfired earlier. We take it out into a field and get it ready, but it misfires. At this point, I think that it's just a snag, so we get the potato out and reload it and try again. It doesn't fire, so I opened the bleed valve a little, then a little more which I guess opened the main valve and somehow flames came out of the barrel, followed by grey-ish smoke. That shouldn't happen. I haven't had time to take a look at it, but I'd like to hear some other peoples' opinions on the problem.

The jamming of the piston can possibly be genarating enough heat to cause some smoke. As for flames, are you useing the solinoid to open the valve? Or did you mod it?

check battery, check that it is hooked up right, check you bleed valve, open it up and wash away pvc dust, check that the valve is on the right way

something must have caused fumes from the glue to ignite since there is no way for the fumes to escape in an unfired pneumatic gun

but smoke is normal and usally is just water vapor.

careful *cough*hyprid*cough*

I'll check the battery, and I know its hooked up right because I did it (that sounds really snobbish....). I'll check the bleed valve, but I know the valve is on the right way (it has a flow arrow!). I don't think it was the glue (and by the I assume you mean PVC cement) because I had built it over a week earlier and successfully fired it numberous times already.

And the last thing I want on my hands (or shoulder) is a hybrid cannon. Leave them to the folks with a death wish and too much time.

your friends thought it was a spudgun, and "spudguns" need hair spray and an ignitor... and they thought, "Hey! this thing is missing an ignitor, lets hook it up to the valve controls, spray some hair spray and click click click"...

since its a pneumatic cannon it makes a lot more sense to make it "actuated" by a pneumatic trigger instead of the typical electric solenoid. it will make your air cannon shoot faster.

research modifying sprinkler valves for pneumatic actuation, theres a video kickin around on this site and http://www.bcpneumatics.com on how to modify typical sprinkler valves this way. Better performance, more reliable, dont need to replace batteries