Any potato cannon enthusiasts?

[Skoad]

I don't get it, for some reason as soon as I try to go to sleep all these weird ideas pop into my head and I can't help thinking about them constantly - making it where I cannot get to sleep.

So here I am again - I have no idea where this came from but all of a sudden in my noggin was a potato cannon!



Now I have never built one of these before, I have seen the hairspray and compressed air. But what came in my head was a little different.

Nice strong steel/iron pipe. Threaded cap at the end with small hole drilled in bottom. Stick a balloon in hole with end sticking out. Hook a nozzle up to it fill it with propane then clamp off the balloon, and remove propane hose and tank. Maybe grease/oil inside of pipe to help potato ejection. Have a potato cut to fit pipe with small gap around it (so it doesn't get stuck). Hook up flame/spark ignition, push button to fire.

What do you think? Too dangerous? Will propane give me some nice *umph*?

[xmetal2001]

So you have a propane filled balloon in a steel pipe? If the propane is in a balloon, how do you ignite it?

Propane makes a great fuel, its very reliable. However, the problem is that it won't ignite unless you have proper air-fuel mixture.

I think somewhere around 3-9% is the range. Around 4.5 being ideal if i remember correctly.

[Skoad]

well i was thinking about using something that makes a flame, rather than a spark. not sure what to use yet, that way it'll just burn through the balloon


the other way I was thinking was in the style of a mortor. You have the balloon and everything the same, but instead of the ignition thing you stick a needle and a lit birthday candle in the bottom of the potato and drop it down the tube.

I think it would be way cool like that, but I didn't know how dangerous it would be - wasn't to sure on how propane would handle.

[Sparq]

I doubt the second idea would work too well...

Mine is pneumatic...just seems easier to me.

[Irelandunfree]

A potato gun should never be too complicated, with the balloon idea you have a problem with a hole being in the back of the gun, and propane escaping could be a problem. Also it would be costly if you buy all steel pipe and conections. A steel barrel may not work too good either. But keep the ideas coming man, I was going to make a very small version of a potato gun, like out of 1" and 2" pvc.....but then I got a job. ;)

[Thordic]

Steel pipe is pretty cheap, it wouldn't be that pricy.

Unless you had a sealed firing chamber, though, you wouldn't get much power behind that spud.

I doubt propane would work much better than hair spray, honestly. You could prolly use propane in a PVC pipe gun, it would be somewhat more explosive than hair spray but not all that much.

Use carburetor cleaner if you want good fuel. Its a little more expensive than hair spray, but hair spray tends to kill your ignition switch. And you can use carburetor cleaner in a PVC gun.

[Thordic]

By the way, if you really wanted to kill yourself, use Butane. Its denser than propane, so you need less of it to get to the same pressures.

[trains are bad]

If you want the ultimate, do like I have been doing for years.....

take a piece of sturdy steel pipe (i used a dock pole I stole from work) And drive it into the ground with a serious driver (i used a backhoe). This is not portable obviously.

drill a touchhole in it.

stick a potato in it.

light an acetylene torch and adjust it to a neutral flame. Put the torch out on the pipe.

fill the pipe up with the perfect air/fuel mixture through the touchhole

light it carefully

[personman]

If you end up making a traditional hairspray potato gun launcher, then I found the perfect igniter. I personally could NEVER get the fricking barbq lighters to work. They're a real pain in the butt and kept shocking me. If you go to wal-mart, go to the camping section where you can buy gas lanterns (probably same section as propane tanks) you can buy replacement lantern igniters. You just drill a little hole in the end of your cap, stick the igniter in there, and it comes with a nut to hold it in place. It works AWESOME it sparks every time, because its made with flint and steel. You eventually run out of flint I think but I'm pretty sure the igniter comes with refills. Its only a few bucks.

Good luck with whatever design you end up doing.

[matmc89]

yea those work, i made one when i was bored at the beach, except i used fireworks and oil.

first took a nice thick peice of pvp and ducktaped it like mad around the bottom so it wouldnt shatter, then made one giant firecracker out of like 30 and put it in the bottom and covered the inside with oil, then made the projectile out of wax and duck tape.