FBpyro Posted June 23, 2017 Posted June 23, 2017 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.
carbonhalo Posted June 23, 2017 Posted June 23, 2017 I found that the BP slurry water made the steel rust very quickly, increasing the resistance to the point of uselessness, so I dip the steel wool in PP lacquer before the slurry to waterproof it. The problem then is the added time to fire the lacquer. They work but take more than a second to ignite.
lloyd Posted June 24, 2017 Posted June 24, 2017 Polypropylene lacquer? Really? 1) I've never seen any polypropylene lacquer available for sale.2) I wonder if you've ever heard of a strange substance known as "nitrocellulose". Hmmmm? LLoyd
OldMarine Posted June 24, 2017 Posted June 24, 2017 I'm just constantly stocking up on the Chi-com igniters before they outlaw them.
FBpyro Posted June 24, 2017 Author Posted June 24, 2017 That is a good theory carbonhalo! though I never used water in the entire process, I melted my nitrocellulose with acetone which is the traditional way. However I suppose there could still be a way that the steel wool could have oxidized inside as it was drying. I left them outside to dry overnight and I didn't think it was particularly humid. The starnge thing is I tested one of the first ones the day I dipped them cause it was dry within 20 minutes, and it lit just fine l! So something happened within 24hrs that changed the properties of them.
carbonhalo Posted June 24, 2017 Posted June 24, 2017 lol Lloyd.... I was referring to ping pong as I'm sure you know..........but polypropylene is soluble in xylene.I wonder how dry FBs acetone was
lloyd Posted June 25, 2017 Posted June 25, 2017 (edited) Carbon, no... that wasn't clear. I tend to spell-out things that might be confused with other things of the same "initials". As a result, I get confused by others' posting of abbreviations that can mean more than one thing. And PP is NOT particularly soluble in xylene at room temp... only slightly. (and I've tried it)------------------------- Material Properties Polypropylene Chemical Resistance: Resistant to the following chemicals at room temperature... Acetic acidAcetoneAcetonitrileAmino AcidsAmmoniaAmmonium AcetateAniline (50% wt)*BenzeneButanolCalcium HydroxideCarbazoleChloroacetophenone*Chloroform*CyclohexanolCyclohexanone*Diethyl Ether*Diethylene GlycolDimethylformamide (DMF)Dimethylsulfoxide (DMSO)Isopropyl AlcoholMethanolMethyl Acetate Methyl ethyl ketone*Methylene Chloride*Perchloroethylene *Dioxane*Dipropylene GlycolEthanolEthyl Alcohol*Ethyl AcetateEthylene GlycolFluoridesFormaldehyde (30%)Formic Acid*HeptanesHydrochloric Acid (30%)Hydrofluoric Acid (40%)Hydrobromic Acid (50%)Phosphoric Acid (85%)Potassium Hydroxide (50%)Propanol*PyridineSodium AcetateSodium ChlorideSodium Hydroxide (50%)Sodium NitrateSulphuric Acid (85%)*Tetrachloroethane*Tetrahydrofuran (THF)*Toluene*TrichloroethyleneTriethelene Glycol*Xylene * denotes partial resistance Not resistant to the following... BromoformButyric AcidCarbon DisulfideDichloromethane EtherMethyl SulfoxidePiperidineTrifluoroacetic (TFA) For a complete and comprehensive list refer to the following (.pdf)Courtesy of Basell Polyolefins. Lloyd Edited June 25, 2017 by lloyd
carbonhalo Posted June 28, 2017 Posted June 28, 2017 I stand corrected regarding polypropylenes solubility.
lloyd Posted June 28, 2017 Posted June 28, 2017 Eh, Carbon... not trying to "correct", just "clarify". Sometimes those 'little things' can lead us down dirt roads! Lloyd
Phil Posted August 7, 2020 Posted August 7, 2020 How long does pong lacquer take to fully cure? I haven't been able to successfully make a batch. I've gotten at best a coating that intermittently sparks if you hold a flame to it but won't stay going if you remove the heat.
Bourbon Posted August 7, 2020 Posted August 7, 2020 It should cure pretty quick but 24 hours is great anyway. If your ping pong balls don't smell heavy of camphor, they are not what your looking for.
SharkWhisperer Posted August 14, 2020 Posted August 14, 2020 (edited) 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. 20170621_185628.jpg 20170621_190837.jpg 20170621_194559.jpg 20170621_190852.jpg 20170621_185648.jpg 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 August 15, 2020 by SharkWhisperer
Arthur Posted August 15, 2020 Posted August 15, 2020 The challenge is the dipping comp used for the pyrogen on the filament. Lots are long term corrosive and slowly eat away the bridge wire or it's solder joints. Oda-ent.com sell premade inert bridgewire chips. What the professional igniter compound is I don't know.
SharkWhisperer Posted August 18, 2020 Posted August 18, 2020 The challenge is the dipping comp used for the pyrogen on the filament. Lots are long term corrosive and slowly eat away the bridge wire or it's solder joints. Oda-ent.com sell premade inert bridgewire chips. What the professional igniter compound is I don't know.Dunno, Arthur, I've stored (forgotten) mine for over a year, exposed to freezing/pretty hot temp cycles in a unit without climate control, and they remain pretty reliable. Whether I just dip deeply (and very lightly on first dip) to cover all exposed wires or attach nichrome twists to the solid copper ends with a drop of superglue. With NC lacquer, and not really paying attention to water content in acetone for this purpose (can't imagine much remains captured in the NC after thorough drying, and might expect little oxygen diffusion to metal to enhance reactions), using BP, perc-Al based, or other similar pyrogens, I've never really had any issue. Maybe I'm just lucky, but never had any identifiable corrosion issues,and they all seem to flame up like new with a hot electric jolt. Steel wool seems to me to be the most likely culprit in causing our friend's ignition failures (and probably much more susceptible to any pyrogen-induced corrosion/rusting than either nichrome or pure single strand copper. I do squeeze my nichrome/copper connections with a needle-nose pliers before supergluing, so that might push the nichrome into better contact with the more malleable copper wire...
Bourbon Posted August 18, 2020 Posted August 18, 2020 I have had great success with Kanthal and Nichrome both. I dip mine in NC then Mg. Just tested one thee other day 3 1/2 years old. Worked like new. I was told not to use Mg anymore because there could be water content in the acetone used to produce the dip. I have never had any problems doing this. Not to say anyone wouldn't have problems, but I'll continue doing so.
WRAITH Posted February 9, 2021 Posted February 9, 2021 Your best bet was to solder them onto double sided pc board. Not one fails the way i make mine. Testing your circuit is a failsafe way by using a torch. Take the end cap off, touch one wire to the body negative & the other wire to the battery negative & with the switch on, the led should illuminate thus completing a circuit.
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