Pneumatic Failures- Post yours here!

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
cyanite
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Thu May 10, 2007 6:53 am

This post is for all those people who have spent a S**tload of money, made a pneumatic, only to have something stupid (like a piston) fail or leak.

If you have general solutions to common problems, other people's problems, or would like to post your launcher's failure, feel free to do so. Try to post photos, or a diagram so that others can help out without having to ask too many questions.

Not playing admin here, but no posting questions about things such as;

Fittings leaking (Teflon tape was invented to solve this)
Off topic eg: paint jobs/ combustions/ social lives.
Plans for launchers

Well anyway, hope this thread helps people solve their problems

Enjoy- Cyanite
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chaos
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Thu May 10, 2007 7:01 am

My first Pneumatic, broke my hand and gave me 7 stitches before it was even finished. :oops:

if that counts
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mega_swordman
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Thu May 10, 2007 7:06 am

Just so I know, is this a topic for saying your problem so others can fix it, or is it like storytime where we look back on our problems? I dunno, I guess it just wasn't clear enough for me to comprehend.

In that case, probably the only problem I ran into was glueing ABS to PVC. In retrospect, it was a really dumb thing to do, but how was I supposed to know(rhetorical, please don't answer that.)
Last edited by mega_swordman on Thu May 10, 2007 7:19 am, edited 1 time in total.
"Never tell people how to do things. Tell them what to do and they will surprise you with their ingenuity." George S. Patton
cyanite
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Thu May 10, 2007 7:15 am

Ok, I'll clear that up.... this is really for troubleshooting, but a few stories on failures would liven this up a bit. So dead clear, ANYTHING THAT HAS GONE WRONG WITH YOUR LAUNCHER, OR ANY INJURIES/ DAMAGES THAT OCCURRED, POST IT HERE, even if you fixed it... tell us about it so others can learn.
cyanite
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Thu May 10, 2007 7:29 am

Well, to get things started, After building my first pneumatic (over/under, ball valve, like a 20:1 chamber barrel ratio) out of PVC, I was so damn excited to use it, I only left the glue to dry for 20 minutes. It felt hard on the outside, so I supposed it was ready. I attached the pump and got the thing to about 60 PSI before BANG! The barrel and ball valve had shot off at the top bend, leaving a very nice dent in the garage door, and an (at the time of course) amateur spudder very shocked.
From then on... 24 hours before usage :lol:

hotwired: I realise that post was there... tucked away at the back of the forums... this a new one, for stories as well as failures.
goathunter
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Thu May 10, 2007 7:38 am

When I was 12 I built my first combustion. I shot it for a while then left it outside for a couple of months.Well, when I did decide to use it next the camber cracked as I shot it.
Moral of story:don't leave your junk out in the elements.
Now days my spud guns have a permanent place in my room.
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Hotwired
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Thu May 10, 2007 7:42 am

Was it physically damaged or do you think it could have been UV damage?
goathunter
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Thu May 10, 2007 7:48 am

I'm guessing UV since I live on the coast.But I was stupid for even leaving it outside that long.I should of stored it in my dad's shop.Mom wouldn't let me bring it inside(it was 7'5" tall) :( Oh well learning experience.And I built it for a science project so it got me a halfway decent grade.Nothing like shooting water balloons at your worst teachers window,All because your science teacher said to do it. :D
spanerman
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Thu May 10, 2007 7:52 am

i had a compression joint fail badly at 120psi the chamber flew off the gun giving me the mother of all dead legs...
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cerberus
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Thu May 10, 2007 8:14 am

I had a piston fail after just a few shots. It used to be made from a 25mm end cap surrounded with a 32mm internal sleeve and a bit of neoprene on the front. The pressure from the 150psi pushing it against a 15mm barrel was enough to break it. I replaced it with a piston made from a bolt a few nuts and washers and some neoprene. That fixed it.
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MrCrowley
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Thu May 10, 2007 2:08 pm

Fire Extinguisher has launched of the end of my paintball gun at 100psi into my garage. :roll:
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spudthug
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Thu May 10, 2007 2:41 pm

while in the testing stage of my newest gun (not psoted here yet, i have two that i finished this week i shall be psoting them soon.) i was testing different pistons.. a few crappy ones cracked and then i got down to my good teflon one..well i superglued the neoprene on, let it set, put it in ,got it all ready to fire, filled it up, at 80 psi all i hear is BOOM!@!@! and my hand was in front of my barrel adapter. i thought my hand got shot! (nothing was in it thoguh) so i looked at my hand and there is a piece of neoprene stuck to it.. ouch.. it hurt liek a mother effer and im never using super glue to hold things for a high pressure cannon together again...
4" piston valved cannon-half done..( i spilt my cement...)

Hybrid- 75% done. need to build propane holder and drill/tap sparkplug hole..
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MrCrowley
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Thu May 10, 2007 3:07 pm

Why didn't you bolt it?
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Brian the brain
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Thu May 10, 2007 3:17 pm

Big ass PVC T valve cannon blew up on me because of ice ammo.
At 100+ psi it nearly cut off two fingers and bruised my leg badly.All healed up now.


Never had a metal cannon fail on me...
Gun Freak wrote:
Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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