SpudFiles

Hey everybody, I was surfing the net when I found this vid:

[youtube][/youtube]

In it, they use a piece of pencil lead to create a light. The lead is attached to a car battery, and it glows brightly for 3-4 min. He also mentions to keep the molten lead away from gas.

SO, I was thinking, why not use it as a dirt cheap igniton sorce for spudguns? You could attach a 12v battery to a switch (the trigger). The switch would lead to two screws which would go into the cannon. These two screws would be attached to aligator clips, which would grip 1/4 inch of pencil lead.

You just saved a piezo. Also, I was thinking of using this idea in a combustion cartrage. I was thinking for a pistol style combustion, and each cartrage would contain a peice of lead, propelant, and a projectile.

Any thoughts? Has this been done before?

That might work, but it could take a long time for it to get hot enough.

Edit: A potential problem might be the heat, pvc doesn't do very well with sustained heat.

Thats a good idea.
In my first combustion (about 2 years ago) i used a similar ignition source, it was a 9v battery connected to a bit of steel wool, the steel wool just ignited and ignited the gas, it works on the same principal. It isn't re-usable like this one though but steel wool is not that expensive and you don't need that much of it.

Hmm, it seemed to get at a blasing hot temp in less than a second in the vid. I mean, if a "punk" can light a wick instantly, a molten peice of lead should too. Also, the shorter the peice of lead, the quicker the ignition. True, it would need to be replaced every hundred shots or so, (unless left on), but I think it would be easy enough. Marco, you think a nine volt would do the job? Or maybe 2 9v in a series?

What if you disharged a cappacitor through it? I know it kills the speed of firing but you could make your own capacitor charger and make it charge faster. ive seen somewhere on the internet a charger that charges one of those cappacitors from disposable cameras almost instantly.

A possibility. But then, you might as well skip the lead, and make a sparkgap. I think running 18v from two 9v should get the lead smoking hot in a sec.

Dang man good point. Well I got 3 9vs lying arround. Imma go try it out and see how fast it gets hot and how small it has to be. Ill get back to you on this tommorow. Great Idea man.

first...it's graphite...carbon can't melt, it sublimes
second..use nichrome wire.. it heats up much better.
order online for it of get it from a toaster.

graphite is very resistant (high in ohms) so if a capacitor was discharged into it it would not instantaneously dump all of its energy it would bleed slowly, and have an effect similar to the car battery. and if you have any experience with electronics you can make a charger that charges camera flash caps lightning fast for id say $5 to $10 (i made one that could charge a350v 1000uf bank in about 5 seconds)

Hailfire753 wrote:Hmm, it seemed to get at a blasing hot temp in less than a second in the vid. I mean, if a "punk" can light a wick instantly, a molten peice of lead should too. Also, the shorter the peice of lead, the quicker the ignition. True, it would need to be replaced every hundred shots or so, (unless left on), but I think it would be easy enough. Marco, you think a nine volt would do the job? Or maybe 2 9v in a series?

Yeah it works, try it yourself if you want. Steel wool is very thin so the resistance will be alot, the resistance will cause heat, resulting in greater resistance creating more heat.

EDIT: But more power never hurt anyone

Don't know how you figure it would be "dirt cheap".

* batteries, $5
* pencil leads, $2
* 9V battery clip $1
* switch $1
* annoyance of having to replace occasionaly $10
* extra annoyance for having to replace when it is located
in the center of a 12" long chamber: $20

Compared to a $12 bbq piezo or a $15 stungun it really is not worth the hassle.

Well I tried with 3 batteries and all it did just got hot =/
I think it needs more amps than volts.

You need the volts to get the distance between spark gaps and you need the amps (or milliamps) to get the temperature up.

I can set paper alight extremely easily with only 50ma @ 10kV....

Michael

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FeLeX wrote:Well I tried with 3 batteries and all it did just got hot =/
I think it needs more amps than volts.

Yep, ya need more amps, or a much thinner conductor.

More Amps:
IIRC, a fresh 9V battery supplies about 5A (but not for very long). A 12V car battery will supply a couple hundred amps. A car battery charger might work as well.

Thinner Conductor:
A thinner conductor has higher resistance and will require lower amparage. A 9V battery will burn a single strand of 000 steel wool in less than a second.
I don't know how effective that is at lighting propane+air.