Stun Gun Ignition Problems

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
The Doktor
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Tue Jul 24, 2007 1:10 pm

OK I have a little problem. I installed a stun gun ignition in my combustion spud, and it was working well except I noticed that my wires weren't quite insulated enough because occasionally it would arc between wires, so I took everything apart and used some +33 electrical tape on the wires which solved the problem, HOWEVER I noticed that there was some arcing INSIDE the stun gun case. I circled what was arcing... except it may be hard to see, I put liquid electrical tape on the problem area. It looks like two metal bands in an "X" form, and it arcs between them.

Has anybody else had this problem?

Maybe I should shorten the distance in the arc gaps?
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pyrogeek
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Tue Jul 24, 2007 1:44 pm

I had a stun gun like that also, a 100k volt one. There were two metal strips that overlayed each other, and arced. Don't mess with them. I tried soldering them together, and then insulating them from each other and it didn't help anything. It just kept it from working. So, in short, just leave it as it is. It's not a defect, that's just how it works I guess.
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jimmy101
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Tue Jul 24, 2007 1:59 pm

Pyro is correct. The "X" is a spark gap and is required for the stun gun to work. Basically, it is the "high voltage switch" between the first and second stages of the amplifier.
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The Doktor
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Tue Jul 24, 2007 8:20 pm

Ok another question for you then... Would too large of spark gaps damage the stun gun? Right now I have three spark gaps, each about 1/2" gap... Do you think that is too much of a gap? I've seen decreasingly dimmer sparks between the gaps which initially lead me to thinking the sparking inside was a problem.
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Pete Zaria
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Tue Jul 24, 2007 8:25 pm

Did you leave the "default gap" of the stun gun alone?

Most stun guns have two sets of electrodes coming out the business end; one set that points inwards towards each other (the default gap) and another set that points outward (towards the poor bastard about to get zapped, these are the main electrodes). If the distance between the main electrodes is too far, the arc falls back to the default gap (because electricity follows the path of least resistance). This acts as a safety feature to prevent damage to the circuitry, also.

If you removed the default gap, you could make one quite simply. Let me know if you need further help with that.

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iPaintball
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Tue Jul 24, 2007 9:29 pm

What's the volatage? If its a 100kv, your gap should not exceed about 1.5" For a 200kv, about 2"
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The Doktor
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Tue Jul 24, 2007 9:49 pm

I'm using a 200K gun. Would going up to a 400K stun gun be overkill? I have one that someone gave to me, but I put the 200K on.

I took out the default spark gap, but I'm not going to make one. I fried the circuts when I was messing around trying to take back off the liquid electrical tape... oops... But i have the 400K to fall back on as long as its not too much.
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frankrede
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Tue Jul 24, 2007 10:44 pm

400k is fine, just add more spark gaps if you don't want to waste any power.
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pyrogeek
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Tue Jul 24, 2007 11:51 pm

I've heard people say that voltage doesn't really mean anything for ignition on a spud gun. Of course, people have also said that there isn't a difference between a single spark and ten. Use whatever you have though and don't worry about it.
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Wed Jul 25, 2007 1:33 pm

Pyrogeek said pretty much everything.

The only thing I would add is to keep the total spark gap small. Even though a "200KV" stun gun should be able to spark 2 to 4 inches I would keep the total spark gap at less than 1/2 inch. You really risk frying the stun gun if you pull the trigger and you don't create a spark somewhere (that is what the safety gap is for, as Pete said). I would suggest;
1. Keeping the total gap length in the gun at no more than perhaps half the safety gap.
2. Leaving the safety gap functional.

These $10 stun gun aren't exactly quality instruments. They appear to have about the same reliability problems as piezo BBQ sparkers. It is not unusual for one to crap out after 10 shots, or for one to last thousands of shots. How long a particular stun gun lasts seems to be a real crap-shot.

Wanna bet your local Police Officer is not carrying a stun gun the Department picked up for $10?
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deadbeef
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Wed Feb 27, 2008 2:59 pm

These $10 stun gun aren't exactly quality instruments. They appear to have about the same reliability problems as piezo BBQ sparkers. It is not unusual for one to crap out after 10 shots, or for one to last thousands of shots. How long a particular stun gun lasts seems to be a real crap-shot.
I have found in a local army shop a really good quality stun gun!
It has 2 years warranty. As you now a lot of stun gun manufactures says "don't do a test discharge for more than 1 sec into air"

Well this baby says do test discharges as many times as you want it wont damage your stun gun. See image below!


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It has pepper spray build in too :) you can take that out if you want.
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Stun gun itself: Scorpy 200
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Test discharge. (it has a quite large spark gap (4,5cm)
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And the last thing it's not a made in China or Korea but it's made in Czech Republic (EU)
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Major Woody
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Thu May 15, 2008 5:53 pm

I have that exact same unit. Of course I also removed the guts and am just using them. I was getting arcs as well, but only when the guts were all packed in tight amongst other wires in the grip of the gun. I was using automotive wire.
I am going to switch out the wire leading off the coil to the spark gaps, and physically separate them as well. Hopefully it works. Will report back.
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