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Fireworks

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akanan

New Member
Hi,

I want to light a Match with one or more 9v pile

I tried the steelwool around the match head, doesnt work...

I heard of resistors they use in fireworks.
They heat up and burns

What kind of resistor would overheat with 1 or more 9v pile?


thank you
 
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BrownOut

Banned
What is a 9V pile? Fuses are often lit w/ nichrome wire. May take more than a 9V battery though.
 

BrownOut

Banned
I have to wonder if there is enough power from those batteries to even light a fuse. Have you thought about making a pack by hooking a bunch in parallel? If I knew what temp was required to light a fuse, I might be able to calculate how much current is required. 'Course, I could just be lazy and google it.
 
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akanan

New Member
temperature doesnt need to be ''SO'' high

just enough to light a wood-match like those u have at home.
 

BrownOut

Banned
What's the coeffecient that converts power to temperature? Is it specific heat???? C'mon, I know there are some thermal guys in here.

If not replies, I'll go dig up my old materials text book.
 
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BrownOut

Banned
I found one reference that says about 3A required to heat 22-ga Ni-Chrome wire to 400 Degrees Farenheit. That shold be a good starting place. The specific heat of the wire it 450 J/(Kg*degC).

Oh, btw, the most efficient heating system is one where the source resistance is equal to the load resistance. a one foot length of 22 ga. ni-chrome is about 1 ohm. Figure out how many 9V batteries wired in parallel would have an output resistance of 1 ohm. My guess is it will be more than you want to use. Me thinks you need a different battery.

After giving this a little more thought, you're going to need about 20A to heat up the wire in less than 5 seconds, if you're trying to get a quick light. That means you're going to need a big-ass battery, like a car battery.
 
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RODALCO

Well-Known Member
9 Volt battery has not enough power for that application.

If you want to keep it reasonable portable, use the sealed type lead gel battery 12 Volts 7 Ah as used in burglar alarms.

These are cheap and will provide enough amps in a wire wound resistor or nichrome wire to trigger the match for your fire works.
 

Mr RB

Well-Known Member
Arson incorporated. ;)

"I want something that will light a little match from a 9v battery, and if possible it has to be reliable to light up about half a ton of old newspapers and rags soaked in gasoline... Also it's best it it works from wireless... Can anyone help me?"
:eek: :eek:
:D
 

Boncuk

New Member
Arson incorporated. ;)

"I want something that will light a little match from a 9v battery, and if possible it has to be reliable to light up about half a ton of old newspapers and rags soaked in gasoline... Also it's best it it works from wireless... Can anyone help me?"
:eek: :eek:
:D

That's a real easy one! :D

Rip off the annoying tin can encapsulation of the battery and stick it in the newspapers. Use a cell phone to trigger ignition by completely shorting the battery. It will heat up in no time igniting the gasoline soaked newspapers.

Don't overcomplicate the circuit to react to a certain code. Just ignite on call. :D

Saves a match too! :)

(Derived from uncle Osama's hobby shop) :D
 
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giftiger_wunsch

New Member
Rip off the annoying tin can encapsulation of the battery and stick it in the newspapers. Use a cell phone to trigger ignition by completely shorting the battery. It will heat up in no time igniting the gasoline soaked newspapers.

As I was reading this thread, that is precisely the reason why I was wondering as to the wisdom of trying to use a 9V battery to start a fire... even if you could produce enough heat to light a match, it'd probably involve shorting the battery and that's not exactly fantastic for the battery's health :rolleyes:

Still, I've gotten a pretty big spark while using a 9.2V battery to test a big-ass motor, so if you just need ignition, why not use a lighter fluid or something similar which could be easily ignited by a small spark, rather than a match which would probably require a fair bit of heat to first ignite?



Footnote: If anyone here has read XKCD, you'll probably understand my temptation to write "big ass-motor" :D
 
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Boncuk

New Member
As I was reading this thread, that is precisely the reason why I was wondering as to the wisdom of trying to use a 9V battery to start a fire... even if you could produce enough heat to light a match, it'd probably involve shorting the battery and that's not exactly fantastic for the battery's health :rolleyes:

In that case it's not meant to stay healthy - not even survive, but enough for the investigators to play with. :D
 

giftiger_wunsch

New Member
In that case it's not meant to stay healthy - not even survive, but enough for the investigators to play with. :D

Hopefully he's using this to light fireworks rather than something more sinister. I still say use a volatile fuel such as a small amount of lighter fluid which a spark can ignite, and use that to light the fireworks' fuses. Easier than trying to directly light a fuse or a match which requires high temperatures, especially as when the battery loses charge it might no longer be able to correctly light the fuse, and you have a dangerous situation where it's no longer safe to approach the firework but you can no longer light it remotely either.
 
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giftiger_wunsch

New Member
What's scary is most of us do have the knowledge to make such a device "FBI COMPUTERS REDIRECT TO THIS SITE" . Good thing we are sane! :rolleyes::eek:

What's more scary is that anyone could gain such knowledge through a google search. It's not exactly the most tricky task anyone's come up with on here, especially when cost of construction / reusability isn't important since it will just get blown to pieces anyway :eek:
 

BrownOut

Banned
A guy I knew when I was in college was a model rocket enthusiast. There is actually a growing community of model recketeers. That's how I knew about NiCr ignitors. But I never saw his arrangement, or ever thought about how much power it would take to create ignition temperature. There's no need to be concerned that a 9V battery is capable of it, per the preceeding discussion.

My estiamte or 20 Amps might have been high, as I didn't really calculate the heat loss to the ambiant air. Instead, I just used the old double the value and hope it's more than enough. Thinking about the 7AH battery idea, you might experiment using different series resistors to keep from burning your wire up, or else put together a brief timer circuit, with a high current output buffer. Use a variable timer from 2-5 seconds to find the optimum arrangement. Dependig on the final setup, you should get between about 45-70 ignitions from such a battery. You may also want to check some model rocket sites or magizines for ideas.

Good luck, and be careful.
 

giftiger_wunsch

New Member
I wonder if there's a specific reason for wanting to do this with a 9V battery? If it was just a matter of lighting it from a safe distance, I would personally just use a longer fuse.
 

smanches

New Member
Much experience here. :D

Use model rocket motor igniters with a match or two taped to them. They work off 9v, at least for a few launches.
 
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Boncuk

New Member
Much experience here. :D

Use model rocket motor igniters with a match or two taped to them. They work off 9v, at least for a few launches.

Who's talking about launches. I was talking about the real things - bombs. :)

When I was 14 I built the strongest bombs of all my friends. We used an abandoned military training area to add a few craters. My biggest one was 15m diameter and 3m deep. :D
 
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