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One week passed, and the cannon was still fueled...

Posted: Wed Apr 23, 2008 9:33 am
by psycix
Today, I got scared the hell out of me by an unexpected surprise...
It all started last week when I was spudding with my combustion cannon (50mm barrel, double spark gap, chamberfan), wich has metered butane.

At the end of the spudding session the butane tank regulator thingy screwed up again and refused to give pressure.
Screwing around with the thing, I accedentically injected ALOT of butane.
Maybe like 2 times my chamber size.
The cannon was not loaded with ammo.
I clicked the igniter, nothing happened. I took off the end cap for about one second and put it back. Still nothing.


I went home, and put the cannon up straight into a corner.
The next day I smelled butane, and found out it came from my cannon.
I clicked the igniter (yes, I fire blank shots inside my house) and nothing happened.



Today, one week further I was searching for something and stumbled across the cannon. I thought hey, why not click the igniter? :roll:
So I did....
BOOM! :shock:

The cannon went off with all its power. The blast of air shredded a poster on the wall into 4 pieces.

In that week enough butane had escaped and I had a good mix in the chamber and barrel.
The barrel was pointing upwards, a bit like this: /
The muzzle end was about 5 inches from the wall.

I think that the reason for this to happen is that butane is heavier then air. And since the cannon was upwards, it couldnt float out so easy. And thus took a week to mix.

Nobody was hurt, and it didnt do further damage. But it could.
So let this be a warning for you.
Always vent your cannon out at the end of a sesion.
:wink:

Posted: Wed Apr 23, 2008 11:20 am
by MaxuS the 2nd
That's just common sense.
You should have thought about the fact that it was still loaded with butane before you left it upright inside your house.

Posted: Wed Apr 23, 2008 11:42 am
by THUNDERLORD
I want to see a damage shot of that poster :wink:
I like your post because it reminds me, Always treat my launcher like it's loaded. It's just tempting to pull the trigger on something that has one.

Luckily, accidents I've had were because I missed something I was aiming at. Like when I shot a blow gun dart through the aluminum door frame. Or shot the arrow through the shed.

Other day I pumped up something too much and a hose went BLAM but it was Cool!!! 8)

Posted: Wed Apr 23, 2008 11:56 am
by Brian the brain
That would not happen with a pneumatic. :D


Always...ALWAYS treat spudguns with the respect they deserve.
Guess you know now..
Good of you to warn others though.

Posted: Wed Apr 23, 2008 12:55 pm
by biggsauce
Had to change yer drawers after that one, huh? :D

Good to hear nobody got hurt, I guess a lesson learned with a little fear is a well-learned lesson.

Posted: Wed Apr 23, 2008 1:11 pm
by Ragnarok
Brian the brain wrote:That would not happen with a pneumatic.
Oh I dunno... if you got the seals right, I could see a pneumatic holding pressure for a week.

Posted: Wed Apr 23, 2008 1:30 pm
by Brian the brain
He pressed the trigger several times.
A pneumatic doesn't misfire like that..

Posted: Wed Apr 23, 2008 2:16 pm
by Ragnarok
Brian the brain wrote:A pneumatic doesn't misfire like that..
Well, of course... that's part of the appeal, isn't it?

Posted: Wed Apr 23, 2008 3:14 pm
by psycix
It was indeed the misfire that tricked me.
I thought that there was nothing in anymore. Especially, a week later. What would you expect?

But yes, a pneumatic wouldnt have that.

For some reason Im starting to like pneumatics more and more.
I might never construct a second combustion again. (maybe ONE)
For the rest: all combustions that I will build will be hybrids (if I ever make one)

Posted: Wed Apr 23, 2008 3:29 pm
by THUNDERLORD
psycix wrote:It was indeed the misfire that tricked me.
I thought that there was nothing in anymore. Especially, a week later. What would you expect?

But yes, a pneumatic wouldnt have that.

For some reason Im starting to like pneumatics more and more.
I might never construct a second combustion again. (maybe ONE)
For the rest: all combustions that I will build will be hybrids (if I ever make one)
Thinking about a hybrid huh? You should check out this post:
http://www.spudfiles.com/forums/small-e ... 14174.html

Posted: Wed Apr 23, 2008 3:52 pm
by psycix
THUNDERLORD wrote:Thinking about a hybrid huh? You should check out this post:
http://www.spudfiles.com/forums/small-e ... 14174.html
Already seen that one.
I even already posted in that thread so you could have known..... :wink:

Posted: Thu May 08, 2008 6:26 am
by dongfang
Hi,

I always stored my combustion upright, unloaded and with the fueling end cap in the breech end OFF. For the same reason :D :D

Regards
Soren

Posted: Thu May 08, 2008 7:51 am
by Tom
Respect comes from two sides :D

Posted: Thu May 08, 2008 9:00 am
by starman
:lol: That story tickled me in a 3 stooges sort of way... Thankfully no serious damage was done. Your ears were probably ringing after that little episode.

Posted: Sun May 11, 2008 4:43 pm
by spudmatic
Incidents like that are the reason my cannons are always stored capless. And I would think that this sort of thing shouldnt happen when you also have a fan in your gun :roll: .