Launcher Failure Analysis Log

[Velocity]

Yeah... PVC hybrids scare me like crazy. Hell, I even get a little nervous around PVC pneumatics. Good thing you are OK... you are OK, right?

[noname]

I'm fine, as I was standing next to the barrel when I shot it. I'll probably scrounge the union and use it in a pneumatic, but I'm never making any PVC hybrid again.

[iknowmy3tables]

I never made my inside out sleeve valve because I didn't know how to use o-ring, most important of all don't try gluing them in place, second if its your first time buying pvc cement don't ask the store asistants, thats how I put teflon paste on all my fittings for a failed gun, I reuse a lot of it and I forget that one of the fitting was not actully cemented so it blew off in my face

[MikeNice]

No pics, bummer, I had a barrel blow up on one of my over / under PVC cannons. It was sched 80 2" PVC. Fired successfully many, many times.
It failed around the union. I think the failure had more to do with the possibility of damaged pvc. I seem to remember that barrel falling off my work bench to the concrete floor. Possibly micro-cracked? Not sure. Needless to say the exploding barrel was a surprise although th PVC didn't explode like some say PVC goes. It broke into about 6-8 large pieces that flew a max of about 15 feet. No one was hurt more than a little cut on my forearm. I think the failure was the perfect storm of a tight spud, perfect fuel / air mixture, and damaged pipe. Spud was no where to be found. The good news is that the cannon wasn't damaged at all and is still in use today. This gun is about 3 years old and still of the same piezo! This is the only failure any of my guns have had. (knock on wood)

[dapaintballer331]

I made a gun out of a UTZ Pretzel Jar, 2 Liter, and a Metal Pole from a pinball machine (leg).

A strawberry was loaded, but the explosion was enough to shoot the barrel off. Somehow, the pretzel>2 liter connection held perfectly.

2 Liter Bottles > Strong
UTZ Pretzel Jars > WEAK
Duct Tape > Weak

Before:



After:

( /|\ Is just a pic of the lighter going off, so you can see the igniter, and how the back exploded)


When the back blew off, no one was standing behind me (it was shoulder mounted) so it didn't hurt anyone.

[Isomer]

Pictures of animals being hurt as the result of spud gunning is not allowed in these forums i think, although the picture does look a bit fake.

[Spitfire]

My Cousins combustions, chamber failed on him here the pics(He requested that i add them before he rebuilds it, as he doesnt have ADSL)
Pipe was pressure rated

[DYI]

That pipe doesn't look very sturdy. Also, with such a thin walled and obviously flimsy chamber, putting a hole in a single layer of pipe for the igniter wasn't a very good idea. This failure would seem to be the result of using materials of inadequate strength.

[rcman50166]

I agree. The pipe used looks way to thin to absorb shock. However if it is pressure rated I'm sure it wasn't shock rated which mean it would be able to hold pressure, just not in quick bursts. The ignitor is obviously the problem in this photo. The origin in the crack is traced diretly back to the ignitor.

[Isomer]

what kind of pipe is that blue stuff? ive never seen it before

[Spitfire]

Its pipe we use in sa For irrigation, pump water from a dam up to a Orhid. Will find out what pipe

[Spitfire]

6 bar pipe, 85psi

[SpudFarm]

and a closed combustion chamber produces 120...

[Spitfire]

yet i use normal drain pipe...I think.... No problems so far

[Jared Haehnel]

Here one that happened a while ago and it was my fault.

I got overly excited about my new combustion and shot the gun before the glue had dried long enough. It made one heck of an explosion and blew the barrel straight of the end of the chamber. The fire singe my eye brows and burnt of a bunch of arm hairs. The kick was pretty serious and the potato went who knows where but it wasn't in the barrel.

Luckily I wasn't seriously injured I hope someone else can read this and have the patience to wait for the glue to set up before shooting it off. The explosion sounded like a gun shot and had my parents running...

I fixed the gun and its been the best combustion I have made to date... but if there's a moral its wait!

If only we could use the fumes from the primer and glue....I wonder how good of a fuel it would make?