Finally finished making a batch of wire-wound igniters dipped in black powder and nitrocellulose lacquer made from ping pong balls; unfortunately 5 out of the 40 I made do not work. I went and measured the resistance of each and somehow all of them have high resistances, I don't understand why because there are only a few turns of thin gauge steel wool strand between both sides of the wire. My best guess is there is additional resistance being built up in the many wraps around both ends where it makes contact with the copper wire. You'd think that it would short together at that point but something must have gone wrong.
Oh well, I went and ordered some talon igniters which I'll use instead this year, I can at least salvage the 24 gauge shooting wire I used to make these.
Are you sure your power source is shooting enough amps to fire? What's "high" resistance to you? Also, why not use known-gauge nichrome wire instead of (cheaper, I know, but nichrome is only about $6 for 500 feet--maybe it was only 200...anyways, enough to last a good while) steel wool strands that 1) likely vary tremendously in thickness (and thus resistance) from strand-to-strand after twisting/untwisting (and it's steel wool so manufacturing specs are not very stringent), and 2) almost certainly requires a more powerful current to fire?
What kind of firing unit are you using? Battery specs? Length and gauge of shooting wire? Single or multiple strands? Pure copper or copper-coated aluminum (a lotta complaints on Amazon about advertising pure and receiving coated)? Have you calculated total resistance from battery (including internal battery resistance), shooting wire, and igniter? Have you determined how many amps you needed to fire the 35 igniters that worked? Was there any delay or instantaneous ignition? You can easily dissolve your coating off of your igniters with some acetone to see if your steel wire remains intact, unbroken, and not rusted.
I make lots of igniters with 34 to 40g nichrome, never bother with the hassle of soldering any more (coat the wraps with pyrogen or use a dab of superglue), and rarely have a failure. And like Old Marine said, you can also get pretty decent Chicom igniters with pyrogen on Ebay (while you can still get them) for a semi-reasonable price. Way way better than that Talon toaster wire/plastic clothes pin shit, in my opinion. Don't accidentally order the Chicom Talon knock-offs. They "usually" work. True Talons are way overpriced, I think. When I press the button, I want instantaneous ignition, not waiting around for the toaster wire to finally burn through some visco coating and finally ignite...You can add a droplet of hot pyrogen in NC lacquer to either your fuse or Talon wire to speed things up a little. A perc/al slurry gets a little hotter than the usual BP slurry.
Edited by SharkWhisperer, 14 August 2020 - 06:13 PM.