stun gun failure

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.
mikespahn
Private 2
Private 2
Posts: 23
Joined: Mon Dec 21, 2009 5:26 pm

Sat May 29, 2010 2:53 pm

what are the biggest factors in a stun gun failing over time, and how to minimize it? how many sparks is the average lifetime? i was going to hardwire just the spark circuit inside my electronics box and glue it down, but if i probably won't get years of use i need to come up with an easier modular way of connecting and disconnecting for replacement. any ideas?
User avatar
mark.f
Sergeant Major 4
Sergeant Major 4
Eritrea
Posts: 3638
Joined: Sat May 06, 2006 11:18 am
Location: The Big Steezy
Has thanked: 58 times
Been thanked: 58 times
Contact:

Donating Members

Sat May 29, 2010 10:15 pm

Depends. Some circuits have an internal spark gap which switches the high voltage capacitor through the final transformer, and some are solid state. The solid-state ones would last a little longer.

As for replacement, solder some quick disconnect terminals onto the circuit.
User avatar
jrrdw
Moderator
Moderator
United States of America
Posts: 6572
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Has thanked: 39 times
Been thanked: 22 times
Contact:

Donating Members

Sun May 30, 2010 4:50 am

Does you electronics box have screw pylons in it? If so, just use a small screw through the hole in the circuit board and snug it down. That's what I did, works great.

Male female quick disconnects for the wiring.
User avatar
jimmy101
Sergeant Major
Sergeant Major
United States of America
Posts: 3199
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Has thanked: 5 times
Been thanked: 17 times
Contact:

Sun May 30, 2010 3:47 pm

Couple things that'll lengthen the life of a typical stungun.

1. As fun as it is to watch it throw inch long sparks, refrain from doing it, it is very hard on the circuit.

2. The gun is not designed to be operated for more than a couple seconds at a time, with a minute or two between firings to let the components cool back off. As an ignition system in a spudgun this isn't a big deal since it'll take at least that long to reload a typical gun.

3. There must always be a suitable spark gap. Or, to put it another way, every time you pull the trigger the system must generate a spark where you want it to. If it doesn't spark where you want then it probably sparked somewhere you didn't want, i.e., across some component on the circuit board inside the housing. That'll cook the circuit pretty quick. So, to get the stun gun to last as long as possible I suggest leaving the default spark gap in place and indeed would suggest shortening the default gap down to perhaps 1/2 inch. That 1/2" is bigger than your ignition gap so if everything else is OK it has no affect. But, if there is a wiring problem, or you ignition gap is too big, then the small spacing of the default gap protects the electronics. (Of course, you want to protect yourself from the default spark gap. :o )
Image
User avatar
bighead33
Private 4
Private 4
Posts: 98
Joined: Fri Feb 19, 2010 2:24 pm
Location: Stonemountain, Ga

Mon May 31, 2010 10:51 am

my stun gun broke to, i think either burnt out a diode or broke the SPDT switch when i was taking it apart :cry:
User avatar
mark.f
Sergeant Major 4
Sergeant Major 4
Eritrea
Posts: 3638
Joined: Sat May 06, 2006 11:18 am
Location: The Big Steezy
Has thanked: 58 times
Been thanked: 58 times
Contact:

Donating Members

Mon May 31, 2010 6:42 pm

bighead33 wrote:my stun gun broke to, i think either burnt out a diode or broke the SPDT switch when i was taking it apart :cry:
Those look like the solid state ones I'm familiar with (from what I can find online they use SIDACS for switching the capacitor instead of a spark gap).

After you took the circuit out (which I assume was completely potted in a plastic case with only four wires coming out ((two for 9V in and two for HV out)) of it) did you try running it on its lonesome? If so, the default gap is critical, otherwise it won't fire and you'll only get a hissing noise from the circuit. Try soldering on some new leads to the HV end (which usually has two VERY short leads ((be careful)) of thin wire) and keeping a very small spark gap (3/16" at most) and then running off of a verifiable input voltage (needs to be between 9 and 12 volts).

The two switches (safety and firing) aren't critical to the circuit's operation. 9-12V on the input wires will operate the circuit the same or better.
User avatar
bighead33
Private 4
Private 4
Posts: 98
Joined: Fri Feb 19, 2010 2:24 pm
Location: Stonemountain, Ga

Wed Jun 02, 2010 12:42 am

mark.f wrote:
bighead33 wrote:my stun gun broke to, i think either burnt out a diode or broke the SPDT switch when i was taking it apart :cry:
After you took the circuit out (which I assume was completely potted in a plastic case with only four wires coming out ((two for 9V in and two for HV out)) of it) did you try running it on its lonesome? If so, the default gap is critical, otherwise it won't fire and you'll only get a hissing noise from the circuit.
nope i did nothing to the circuit i was just studying it. but you do intrigue me
, why wouldn't the circuit work if i did run it on it's lonesome
User avatar
mark.f
Sergeant Major 4
Sergeant Major 4
Eritrea
Posts: 3638
Joined: Sat May 06, 2006 11:18 am
Location: The Big Steezy
Has thanked: 58 times
Been thanked: 58 times
Contact:

Donating Members

Wed Jun 02, 2010 4:22 am

IF the air-gap between the two HV electrodes is too great then it will not work at all. Taking it out of the case removes the default gap.

Just make sure that the HV wires are less than 3/16" from each other and it should work fine.
User avatar
bighead33
Private 4
Private 4
Posts: 98
Joined: Fri Feb 19, 2010 2:24 pm
Location: Stonemountain, Ga

Wed Jun 02, 2010 4:04 pm

all right, thanks.
Post Reply