Nichrome Wire AWG

[xray45]

Hello to all,
I was wondering what gauge nichrome I should be using. I am wrapping around the visco and not using any type of composition to help igntion.
16 volts will be used to power the nichrome.
I just don't want to put too much power through that it breaks too fast without igniting the visco and too little and it takes forever.

Before I get slammed for it, the 16 volts is what I had here to use for power so it's being used. Any help would be great.

Thanks

Ray W.
"Today It's Fire, Tomorrow It's Ashes!"

[Deweycoon]

This may help you.
http://www.pyrouniverse.com/show/fusing/joeematch.htm

[PyroZ]

I have had success with a 12 volt system using 40 AWG nichrome. There is a place on ebay selling it for $3 and change for 75 feet.

Initially I used to do just a few turns around the visco with no extra primers, and had very good results. The ultimate solution I have found now for a lower voltage, quick ignition solution with nichrome is the following.

I take the 40 AWG nichrome and with a sewing needle pierce it diagonally through the visco, being sure to pass through the powder core of the visco. This leaves a little tail of nichrome sticking out to which one can use small alligator clips to attach the firing wire for that cue.

Since it can prove to be a real pain to "sew" nichrome through the fuse of every firework you plan to e-fire, a more practical solution is to instead make your own igniters using visco and nichrome. For example take a couple of inch piece of regular or preferrably quick visco and diagonally pass the nichrome through it the same way as described above. A small dot of super glue or some other compound around one of the points where the nichrome enters the visco, helps secure it from falling out.

If you produce a bunch of these igniters, you have them ready to use whenever you want to e-fire a firework. You can then attach one of these homemade igniters to the visco of the firework using tape or zip ties. Just attach your firing wires to the nichrome of the igniter and away you go.

Since I went off on a tangent here, back to the basis of your questions. 31-40AWG should be a practical range for your use. 40 probably a preferred choice, but that size and smaller (higher AWG, 40+) gets crazy to handle since it is so so thin.

Good luck and be safe!

[Deweycoon]

Yep I also use a needle to put 40 ga. nichrome through the powder core and my igniters go instantly with 4 AA batterys or 6 volts.

[MNPyro]

I have 36 AWG nichrome sitting at home, and as the wrapping around the fuse and piercing the powder core work very well, you may want to use a lower AWG if you are wrapping. Maybe something like 32-36 AWG as you want to make sure it heats the fuse enough before it breaks. My personal opinion/suggestion would be to use 40+ AWG for making ematches soley...36-40 AWG for piercing the powder core, and anything above that only for ematches.

This just prevents any nonfires and also assures your fuse will get lit properly without the nichrome breaking early.

MNPyro

[JoeRatman]

Well, I usually use 24 volts for firing, but have used 12 in some situations. YOu might be fine with 16 volts, but there is some additional information besides the volts and the gage and length of the nichrome wire.

What gage of copper wire and how much (feet) are you using to get from your battery (and firing panel) to your igniter? This information is needed to figure out how much resistance there is in your circuit. With the gage of the copper wire and its length, you can calculate the amount of resistance. You also need size and length of the nicrhome wire. YOu can then calculate its resistance and add it to the resistance of the circuit.

Once you have the resistance you can figure out how much amperage is flowing through the circuit. Given 16 volts and the resistance we can calculate the amperage using ohms law.

amperage = volts / (resistance of copper wire + resistance of nichrome wire)

amperage = 16 / (total resistance)

Calculating resistance and the resistance of various gages of copper wire can be found on this page:
http://www.pyromate.com/Basics-of-Electrical-Firing.htm

Once you know the amperage you can use this table:
http://www.wiretron.com/nicrdat.html

to figure out how much amperage you will need to heat up or break the nichrome wire. If you have enough amps, then the wire will heat up (or break) and the fuse will ignite.