Aces High Bulletin Board

General Forums => The O' Club => Topic started by: Octavius on August 06, 2003, 03:20:02 PM

Title: kartofel kannon
Post by: Octavius on August 06, 2003, 03:20:02 PM
Out of boredom, a few buddies and I decided to build a potato gun... it's marvelous... when it works.  

We used two 3' sections of 3" and 2" diameter PVC piping (3" = chamber, 2" = barrel).  

For the ignitor, we decided to buy a $12 grill-ignitor and wire it to two wood screws drilled on opposite sides of the firing chamber.  Inside, the two terminals are about 1/8" apart.

Here's the problem:  Using hair spray ("Rave" brand, industrial strength), we'll get about 2 successfull firings out of 10 attempts.  The lighter is definitely working, but it doesn't have enough oomph to jump the gap and ignite the fuel.  We discovered the hairspray would partially coat the terminals and screw our spark.  But even without hairspray, a spark rarely occurs.  We've tried moving the screws closer together with no avail.

We're thinking about using a different fuel (heard propane works the best) or scrapping the current ignitor and finding something else.  We *do* have a tesla coil and I'm positive that'll make a spark... we just have to fix it first :D  Would a chain of 9V batteries and a switch make a decent spark?  

Any comments / suggestions?
Title: kartofel kannon
Post by: Tarmac on August 06, 2003, 03:21:17 PM
don't look down the barrel after a misfire, especially if you're shooting frogs.
Title: kartofel kannon
Post by: boxboy28 on August 06, 2003, 03:24:19 PM
first things first Use ether (starting fluid)  and secondly make sure the arse end can unscrew! after every shot you need to revent the combustion chamber(un screw end and blow it out) just to give it oxygen to ignite!
Title: kartofel kannon
Post by: Gadfly on August 06, 2003, 03:27:30 PM
Give us the link to your hometown paper so that we can read about the explosion from a primary source.
Title: kartofel kannon
Post by: Octavius on August 06, 2003, 03:27:56 PM
hehe Tarmac, I read about the frog(s) :)  

Box:  We already have an un-screwable end and it gets ventilated fairly well.  

And using different fuels such as ether / propane / farts won't make much difference if the ignition wont spark! :)
Title: kartofel kannon
Post by: boxboy28 on August 06, 2003, 03:31:41 PM
well thats the same prob my buddy has with his gun ill ask him what he did!  clean off the terminals and move them closer together! is the ignition on the side or the butt end?
etrher is much more flamable so it ignits easier too!
Title: kartofel kannon
Post by: Octavius on August 06, 2003, 03:34:54 PM
screws + ignitor are mounted on the sides.  They're positioned a few inches from the end (arse).
Title: kartofel kannon
Post by: boxboy28 on August 06, 2003, 03:59:41 PM
you might want to move them up about 1/2 way in the cumbustion chamber! when you spray all you fuel its gonna gather up there!
Title: kartofel kannon
Post by: SKurj on August 06, 2003, 05:50:20 PM
sounds like a fun project for a 14 yr old....


So errmmm what is it for?


SKurj
Title: kartofel kannon
Post by: Octavius on August 06, 2003, 05:57:34 PM
14 yr old?  http://spudtech.com/detail.asp?id=26

Who hasn't heard of or built a potato gun?
Title: kartofel kannon
Post by: Curval on August 06, 2003, 06:22:05 PM
Quote
Originally posted by Tarmac
don't look down the barrel after a misfire, especially if you're shooting frogs.


Saw a show about a blind kid who got that way doing EXACTLY what you describe about 2 weeks ago.

Please be careful Oct.

Now go and play with your friends.  There's a good lad.  ;)
Title: kartofel kannon
Post by: Animal on August 06, 2003, 06:33:38 PM
Aim it at your crotch.
Title: kartofel kannon
Post by: Ripsnort on August 06, 2003, 06:59:43 PM
Quote
Originally posted by Animal
Aim it at your crotch.


Sometimes you say the strangest things...I wonder if its bad weed that we export for consumption south of our border.
Title: kartofel kannon
Post by: Stringer on August 06, 2003, 08:26:38 PM
LOL Gadfly!
Title: kartofel kannon
Post by: Mark Luper on August 06, 2003, 09:32:40 PM
Quote
Originally posted by Octavius
14 yr old?  http://spudtech.com/detail.asp?id=26

Who hasn't heard of or built a potato gun?


Along with a a large collection of other information, I first learned of "potato guns" on this BBS. :) Oh... and no, I have never built one either.
Title: kartofel kannon
Post by: Octavius on August 06, 2003, 10:11:14 PM
Quote
Originally posted by Mark Luper
Along with a a large collection of other information, I first learned of "potato guns" on this BBS. :) Oh... and no, I have never built one either.


hehe... allow me to rephrase:  Who hasn't heard of or built a potato gun with the exception of Mark and anyone else on this BBS?  :D
Title: kartofel kannon
Post by: Tarmac on August 07, 2003, 01:30:04 AM
Quote
Originally posted by Curval
Saw a show about a blind kid who got that way doing EXACTLY what you describe about 2 weeks ago.


And that incident is exactly what I'm referring to.  :)

And LOL at Animal.  Would that make him a candidate for the darwin award, since he couldn't breed?
Title: kartofel kannon
Post by: troxel on August 07, 2003, 04:54:26 AM
My guess is that hairspray residue is causing problems with the electrodes.  Try using butane as a propellant.  It burns much cleaner.  You should be able to find these at the neighborhood drugstore for lighter refills.  Getting a good, consistent fuel-air mixture is going to be the tricky part, but that is true for any combustible gasses.

I'm not sure which grill starter you are using, but piezoelectics should do the trick.  You can canabalize an electric lighter for this part.  They tend to easily arc over a 1/8" gap.

Next, you should look at your projectile.  How accurate can a potato be?  Perhaps you should be firing well formed speckknoedel instead ;)
Title: kartofel kannon
Post by: SKurj on August 07, 2003, 01:31:22 PM
heh never built one, but as a young kid we had a couple potato handguns.   Ya could buy them once upon a time in England at least.  Though these things were old when we got our hands on them.  Can't say how well they worked, I have a feeling they didn't work well or I'd remember more...



SKurj
Title: kartofel kannon
Post by: cobia38 on August 07, 2003, 11:51:07 PM
Try model rocket ignighters they are cheap,and should
  provide hot enuff ignition source.  have fun :D