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PostPosted: Fri Jul 01, 2005 1:59 pm
by BigBang
Hi Gang,

Here is another project I just finished this week - in preparations for the 4th of July! It is a carbide cannon. It doesn't launch anything, but does make a VERY loud bang. I got the idea from one of my cousin's kids who built one from the plans in "Backyard Ballistics." Mine is quite a bit different, however, and is of my own design. The overall length of the cannon is more than two feet (EDIT: It is 33 inches long to be precise). The barrel is made of 1.25" SCH 40 PVC. The reservoir is made of 2" SCH 40 fittings, and the legs are of 1" SCH 40 PVC.

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Here is a closeup of the reservoir. I am using a modified Coleman lantern lighter for ignition.

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Here is the fuel source and loader. I just put a pea sized amount of Bangsite in the hollowed out recess in the loading rod. As I screw the end cap into the back end of the reservoir, the Bangsite spills into the reservoir, which has previously been filled with water. The Bangsite (just powdered Calcium Carbide) disolves and gives off acetylene gas. The spark from the lantern lighter does the rest. BANG! Man, is it loud!

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It turns out that the Bangsite is made by the Conestoga company. Guess what else they make? Big-Bang cannons! ( Who knew? Well, probably everyone but me.

Note to PCGuy: Feel free to use these images at SpudFiles if you wish.

Happy 4th of July,

PostPosted: Fri Jul 01, 2005 2:19 pm
by spudman029
WoaHWoaH, might not be the best idea to use acetylene gas in the sch40 cannon, or any cannon. But nice paintjob.

PostPosted: Fri Jul 01, 2005 2:45 pm
by SilentJ
I like the paint job! The stand looks sweet, too. Good work!:D

PostPosted: Fri Jul 01, 2005 2:57 pm
by sonicst0rm
acetylene + potato guns = death


Acetylene explodes, it doesn't just burn. My friend threw some calcium carbide in a puddle, and threw a sparkler in it. Sure enough, it made the biggest explosion i've ever heard.

PostPosted: Fri Jul 01, 2005 3:27 pm
by Krazy_K
Yeah that's not really too safe. It looks great but think about using propane or deodorant, acetylene, as sonic said, detonates, propane deflagrates and is much safer. It looks like fun, but only until it explodes in your face.

PostPosted: Fri Jul 01, 2005 3:46 pm
by spudman029
Ya dont use that bangsite, just dont. Im glad that you get a loud noise, but that loud noise is there for a reason. To get similar results, on the muzzle end of the resivour, cut away so you have just enough pipe left to attatch a sch80 union. Little things called burst discs are inserted into the union, and when you fire, the gasses blow through the burst disc[usually foil], and it makes a loud bang. Here is a paint pic to show you what i mean.
EDIT-Make sure that you glue the union with proper pvc cement

EDIT-The only reason the fuel is safe in those BigBang Cannons, is that their cannons are made from cast iron, not pvc plastic.

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PostPosted: Fri Jul 01, 2005 3:55 pm
by Mr.Plow
Great paint! That looks really smooth and well done.

Since there is no projectile, I think this cannon won't explode, even when using acetylene. There is so little gas made that I doubt it would blow. I've got a carbide cannon as well that I bought from a flea market, and considering it is made from stamped thin gauge metal and has never showed signs of failure, I wouldn't worry.

Still, since I'm such a fraidy-cat, I personally wouldn't be right next to it when firing. If it were mine, I'd have a BBQ ignitor with a long, long cord :evil:

I know I'm a wimp, but I'm a wimp with all his limbs intact:D

PostPosted: Fri Jul 01, 2005 4:02 pm
by saladtossser
Awesome paint job, i swore it was ABS until u said pvc, that fuel is clever. that is the greatest bi-pod i have ever seen, it is just so shiny and have a odd look to it but i like it

PostPosted: Fri Jul 01, 2005 4:51 pm
by BillyBobJoe
VERY NICE! I love the clean construction - just like all of your other cannons.

Considering the plans were in Backyard Ballistics, they should be safe (and like Mr. Plow said - his is thin metal)

PostPosted: Fri Jul 01, 2005 5:23 pm
by jimmy
Very nice. Really like the fueling system.

Folks are being pretty paranoid, without anything in the barrel the gun isn't going to generate much internal pressure.

When I was a kid we had a bangsite canon (the big one). The body is cast iron but the barrel was thin sheet metal help in place by a single pin. The pin could be removed so the barrel could be removed.