Posted: 1/2/2007 7:04:08 PM EDT
| I figured tonight I just had to build one. Anyone have some plans? Is the expansion chamber necessary? I was thinking of building one with a plain piece of "2 pvc and configuring some way to keep the propane bottle attached to the cannon so you'd just have to turn a valve for a few seconds then you'd be ready to go again. |
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Look around on the internet and copy what you find. All have a chamber that is larger than the barrel. Propane huh? Lemme know how that works out. I've heard of PVC shrapnel wounds from people using propane. Anyway, it costs like 20 bucks to buy the parts from Lowes. What you need: -12-18" section of 3.5-4" PVC SCHEDULE 40 or SCHEDULE 80. Don't use cellular-core PVC 'cause it's not pressure rated. Ouchies. -3'+ section of 1.5" PVC sch40/80 ..... 2" is kinda big and will sacrifice pressure. good luck finding big enough potatoes! -For the breech, you need a threaded shoulder and matching threaded end cap. -For the transition from 3.5/4"-1.5", you need some reducing sections, use as few as possible to get the job done -2 couplers to attach breech and transition sections -BBQ ignitor -2 screws + wiring to form spark gap through chamber walls -PVC welding compound and primer DON'T FORGET THAT PRIMER Have NOTES: Right Guard burns cleaner than hair spray. Let the PVC welds cure for 24 hours. Don't point that sucker at your face if it doesn't ignite. Sometimes the fuel will burn really slowly for a few seconds and then WHAMMO you've got... well, a headache would be a gross understatement hmentburntlatke.com for an idea. Remember that you still need to introduce new air each time you fire, which kinda nullifies the speedy propane idea. http://www.burntlatke.com/jpg600/lp-overall.jpg The ultimate in spud weaponry. I don't approve of propane in a PVC setup, but what the hell, it's sooooo badass. |
| we just used hairspray and a bbq ignitor. it was a barrel-larger chamber for the hairspray- and then a cap that screwed in.......you loaded the spud into the barrel sprayed some hairspray into the chamber and then screwed the cap on and clicked the ignitor....it launched them things way out there |
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I prefer using ABS sewer pipe. 1.5" fo rbbl, and 3" for chamber. It's already tactical black to boot. Screw on cap on end, bevel the muzzle so the spuds cut to size when loaded. Cut a dowel or broomstick to the length of the bbl minus 6". We use BBQ igniter buttons since they are more trigger-like than the spinny lantern sparkers. Propellant: hair spray (get the cheap aqua-net minus the extras hold, unscented so the enemy won't detect you). Propane also works... The one we made looks like a Browning machinegun. |
| Never had one myself, but I can tell you I was damn near on the receiving end of one once. Shooter had to be 60/70 yards away, shooting at a bullseye painted on a sheet of 3/4 inch plywood, laid out in the warehouse we were working in. I stepped into the line of fire and out just in time to see the spud put a hole clean through 3/4 inches of plywood. Was going to punch the fuckers lights out but it turned out to be the boss shooting the thing! |
I've heard that stuff is dangerous b/c of its brittle nature. |
I'm not sure why, but this thread made me think of this..... www.buckstix.com/howitzer.htm |
I've heard it reported tho that Right Guard has changed their formula somehow to make it less flammable, i don't know if it's true or not, just what i heard. |
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Be careful. I know a guy who got rolled up by the sheriff for a spud gun. Not sure of the exact charge, but it was a few years ago. Something along the lines of 'destructive device'. It was a headache for him for sure. He eventually beat the rap, but it was a PITA. Happened in Utah County, UT. |
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The ATF says the spud gun is not a destructive device. You can fire it anywhere that doesn't have a local law against it. The noise it makes is probably the only thing they can get you on, as long as you're careful where you aim. For me, that is anything within 500 yards at +/- 10 degrees www.spudtech.com/content.asp?id=13 |
WD-40 used to work good too, but they changed something and it just ain't the same... |
+1 I used the ABS with good results too. Mine was 7 1/2' with a 5' barrel and 2 1/2' chamber. The barrel was 2" and the chamber was 4". This beast lobbed a potato very hard and far. Don't shoot these in the city limits if your city says anything that fires an object and has a propellent is a firearm. I would still have it but thanks to the PPD it's gone. |
In college a buddy of mine had a 6 foot piece of cold rolled steel pipe, capped at one end. It was a perfect match for a tennis ball with the hair burnt off. He would spray 2 seconds of starter, ram the ball down to the right depth using a calibrated ramrod, and then apply a jolt to the spark plug welded into the capped end. It would put a tennis ball into the next county  . No matter how hard we tried to get it to shoot straight up, we never found a single tennis ball.
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How far down the pipe would you shove the ball? i.e. what was your chamber length? |
Around 8 inches. We had to fire it quickly or the pressure would bleed off. |
Wow I never had a problem with using acetylene (we used calcium carbide + water)...were you using oxy-acetylene?(i.e. added more oxygen than the what was in the atmosphere) Worst I ever did was crack the end cap which was an easy replacement. I can confirm that lubed up racquet balls work much better than potatoes though! |
Well, gotta be honest, the build quality would've made Century Arms proud. We were using a calcium carbide/water mix to make the acetylene. The barrel unscrewed from the chamber, potato loaded into the back of the barrel, dump a capfull of CaC2 into the chamber, screw barrel in, light piece of cannon fuse sticking out of side of chamber, run away. It was fun. 
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CRAP! You would have to name the county I LIVE in. out of all the counties you could have said. I want to build one but don't need the damn cops giving me crap. Anyone else in utah built one of these and ran into trouble with the law? |