share your cannon accidents!

DYI · Mon Jul 16, 2007 2:30 pm

Both of my major spudgun accidents were with an Oxy-MAPP gun that I built a while back, although the first one was pretty minor.
The first time, I was down at a lake firing golfballs, and the end plug hadn't been tightened enough (I used it to vent the chamber after firing, the fuel injection was plumbed directly into the chamber). When I pressed the ignition, the bang was much louder than usual, and left my ears ringing for thirty seconds. When I stepped out from behind the 3/4" plywood that I used as a shield, I found that the end plug had fired of the back, and hit the plywood hard enough to buckle the back of the sheet. The fueling rig was also destroyed, putting the gun out of commission for a week. When I repaired the fueling rig, I also added a gauge, and made the chamber completely airtight. I 'permanently' attached the end plug, since my new design allowed for venting with an air compressor.
I then calculated the pressure of each gas needed for a perfect mixture, and decided to test my calculations by putting a burst disk in the union at the front of the chamber and trying to get ignition. I filled the chamber to 4 psi with oxygen, and added the required MAPP gas. After pressing the ignition several times I was getting frustrated, and decided to try just one more time and then vent the chamber.
I think I blacked out for a few seconds when the mix detonated, because I remember touching the two wires together, and then I was suddenly lying on the ground, unable to hear, see, or feel the right side of my face.
The end plug had been torn off its threads, and hit the concrete foundation of my house, leaving a 3/4" deep dent which is still visible. The blast acually knocked over lamps inside my house, and I consider myself lucky to have sustained no serious injuries.
I completely regained my hearing within one hour, and the scars and bruising on my face had faded away one week later.

mopherman · Mon Jul 16, 2007 2:35 pm

yeah.... dont use oxy with plastic pipe!

DYI · Mon Jul 16, 2007 2:38 pm

I know that now...
Lucky it was ABS and not PVC though. I'd have really been screwed then.

mopherman · Mon Jul 16, 2007 2:42 pm

yup. you would be dead and we would get a bad rap on the news.
i think you sould remake that cannon in metal.

DYI · Mon Jul 16, 2007 2:49 pm

Well maybe not an exact remake, but I will do a smaller version in steel sometime, using a proper metering system rather than the inaccurate chamber pressure one. It will use remote ignition, and probably go up to the equivalent of a 2 or 3x mix (about 8psi total before firing if using O2 rather than air).

Hubb · Thu Jul 19, 2007 1:44 am

The first cannon I made was a simple combustion that used hairspray. I fired it several times and thought it would be a good idea to try and get more power by spraying more hairspray. Of course, this flooded the cannon and it did not fire. I opened the ball valve on the back (I designed it with a ball valve instead of a cleanout) and took a look inside. I then thought it would be a good idea to "make sure the igniter was still sparking" so I hit the piezo and took a fireball in the face. I had no eyebrows for almost a month (it didn't really hurt but the smell of burnt eyebrows was awful).

chaos · Thu Jul 19, 2007 1:50 am

hubb017 wrote:The first cannon I made was a simple combustion that used hairspray. I fired it several times and thought it would be a good idea to try and get more power by spraying more hairspray. Of course, this flooded the cannon and it did not fire. I opened the ball valve on the back (I designed it with a ball valve instead of a cleanout) and took a look inside. I then thought it would be a good idea to "make sure the igniter was still sparking" so I hit the piezo and took a fireball in the face. I had no eyebrows for almost a month (it didn't really hurt but the smell of burnt eyebrows was awful).

aww nasty ive nearly had that on quite a few occasions

mopherman · Thu Jul 19, 2007 1:55 am

wow, i just had the best idea. Use a combustion chamber to shave! You could just blast the hair off! lol barbershop flamethrower ((((( best band name ever posted by accident on 07/18/2007 23:48 PM)))))

EDIT: jut realized how dumb this post is. sorry

DirtyDan · Thu Jul 19, 2007 2:13 am

Three days ago I finally installed my fan into my new combustion and not knowing how much it would increase my distance I went ahead and gave it a test fire at the nearby playground (about 120 yards away from my backyard). Little did I know it was gonna go sailing over my projected target and land about 5 feet away from some dude outside mowing his lawn. He was rather startled and stopped his mowing to pick up the potato round and look right at me. Apparently it's pretty easy to spot 8 feet of bright white pvc (and the 6 feet of bright white me) from even hundreds of yards away. He ran inside his house (at which point I followed suit, taking my gun with me) and he came out 30 seconds later on his cell phone. Presuming that he was informing the police of my apparent 'assault,' I hid my gun in the attic and drove to my friend's house just to be on the safe side... and as far as I know the cops never showed up, but then again I wasn't at home waiting for them... Anyhow, I felt pretty bad since I'm sure he thought I was just some punkass kid trying to shoot him when that wasn't the case at all. Hell, I didn't even know he was out there... oh well...

chaos · Thu Jul 19, 2007 2:45 am

DirtyDan wrote:Three days ago I finally installed my fan into my new combustion and not knowing how much it would increase my distance I went ahead and gave it a test fire at the nearby playground (about 120 yards away from my backyard). Little did I know it was gonna go sailing over my projected target and land about 5 feet away from some dude outside mowing his lawn. He was rather startled and stopped his mowing to pick up the potato round and look right at me. Apparently it's pretty easy to spot 8 feet of bright white pvc (and the 6 feet of bright white me) from even hundreds of yards away. He ran inside his house (at which point I followed suit, taking my gun with me) and he came out 30 seconds later on his cell phone. Presuming that he was informing the police of my apparent 'assault,' I hid my gun in the attic and drove to my friend's house just to be on the safe side... and as far as I know the cops never showed up, but then again I wasn't at home waiting for them... Anyhow, I felt pretty bad since I'm sure he thought I was just some punkass kid trying to shoot him when that wasn't the case at all. Hell, I didn't even know he was out there... oh well...

your lucky mate.

over here where they are illegal, i took mine over in a paddock where nobody ever is (so i thought) i let off about 4 shots without taking notice of anything but the destroyed aerosol cans and shredded phone books, anyways i start walking back to where i was shooting from (an old tree stump) and i notice a white 4x4 on the hill above me about 250-300m away from me, as i looked closer i see 4 figures standing out the front of the car leaning on the hood just watching me

now just imagin seeing a 16yr old kid, with a near 6ft (with the silencer on) all shiny stainless gun looking thing letting off shots

now i absolutely craped myself i had no idea how long they were there and the y could have called the cops 5mins ago and they could have been on there way.

anyways i just threw everything in my bag and walked home like i was finished doin what i came to do.

Now i got to the fence next to the road and guess wat i saw? yep a cop car.. now i was sh!ttin bricks at this time, but luckily i had the gun in the bag, so well they just kept going.

man i was worried but well it all turned out ok in the end i got home without a hassle so yer thats the closest ive come to being caught.

DirtyDan · Thu Jul 19, 2007 3:10 am

wow, nice story... well I'm glad you were able to make off with your gun n' everything. I can only imagine the shit you'd be in if the cops had gotten ahold of you... and having your gun taken away definitely wouldn't be too enjoyable... but hey... you got away, so more power to ya!

tylerthetatertosser · Thu Jul 19, 2007 3:12 am

well my spudgun accident was acctually today, I was showing my friends my simple combustion gun and then bam when i shot the gun the clean out adapter exploded shooting the cleanout cap and threads backwards

SpudBlaster15 · Thu Jul 19, 2007 12:46 pm

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chaos · Fri Jul 20, 2007 1:19 am

SpudBlaster15 wrote:The only major accident I have experienced would be my advanced combustion launcher explosion.

thats a shame,

i hope the hybrid doesn't end the same, i'd rather a hybrid die from massive recoil into a wall or something not an explosion with steel shrapnel.

SpudBlaster15 · Fri Jul 20, 2007 1:36 am

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