thehole Posted July 16, 2023 Posted July 16, 2023 Hey folks, wasn't sure of the best spot to post this, so this is definitely a newbie question!I'm looking for e-match blanks; preferably the entire match with nichrome wire, just not dipped in anything yet.Located in Canada, but will consider ordering from U.S. MJG charges nearly $60 to ship to Canada.So far Alibaba is the cheapest option from vendors in China, but I'd prefer to order from here in N.A. if possible to keep shipping times to a minimum.Thanks! 1
Arthur Posted July 16, 2023 Posted July 16, 2023 Beware! Soldering to nichrome wire requires a special phosphoric acid flux, usual fluxes don't work.
Richtee Posted July 16, 2023 Posted July 16, 2023 I don’t get why you people just don’t “roll yer own”. A roll of 28-30 Ga nichrome, some mill dust/fines and some double based powder. Couple drops of acetone. There’s no need to solder to the nichrome. Use a long enough length to “double” the ends to about .5 inch of the center, twist for a nice loop at either end for clip connections.
Arthur Posted July 16, 2023 Posted July 16, 2023 (edited) DIY igniters are usually relatively insensitive so need a high voltage to fire them quickly. youtube.com/watch?v=KChLe4q0VP0 Edited July 17, 2023 by Arthur
thehole Posted July 16, 2023 Author Posted July 16, 2023 Beware! Soldering to nichrome wire requires a special phosphoric acid flux, usual fluxes don't work.Thanks for the heads up! I don’t get why you people just don’t “roll yer own”. A roll of 28-30 Ga nichrome, some mill dust/fines and some double based powder. Couple drops of acetone. There’s no need to solder to the nichrome. Use a long enough length to “double” the ends to about .5 inch of the center, twist for a nice loop at either end for clip connections.Wanted to break down the diy process one step at a time (this time it's the pyrogen).Is there an advantage to not soldering the nichrome and just letting it hang there between the paired wire? I'd be worried the nichrome would easily snap without the support of the e-match chip.
Richtee Posted July 16, 2023 Posted July 16, 2023 DIY igniters are usually relatively insensitive so need a high voltage to fire them quickly. A solid 12V and at least 20Ga fire wire will about blow that 30 Ga nichrome up. Or, go to 24. 2 4 AH sealed lead acid bats would prolly be overkill... I’d wager in the low milli-second range for fire. I have a vid here of me igniting visco...hmmm... https://www.amateurpyro.com/forums/topic/14359-electric-igniter-to-visco/?p=195456 As far as mechanical support...I dunno. I make my own rocket igniters...and have no problem. Connect to the N wire with a decent quality flat contact alligator clip. Engineer, young man. The Lord gave you a head, use it!
Arthur Posted July 17, 2023 Posted July 17, 2023 A conventional igniter of commerce will fire at about half an amp for 25 milliseconds, but it's made with fine nichrome wire to be sure of this. DIY igniters work from up to 1 amp. It's not a problem til you want to use a long wire where an amp relies on a lot of volts being available.
Arthur Posted July 17, 2023 Posted July 17, 2023 A Commercial igniter will have a bridgewire of about 45 - 50 gauge (B&S or British SWG) usually the double sided board chip will be 1 - 2 mm thick and that length of wire will be about 1 ohm. It's essential to be very regular in manufacture as the resistance of each igniter governs how fast each will function, if one is too slow it may not function because the current stops when the first bridgewire is broken. 1
thehole Posted July 17, 2023 Author Posted July 17, 2023 A solid 12V and at least 20Ga fire wire will about blow that 30 Ga nichrome up.Okay that makes sense, I was envisioning the same gauge that I (can barely) see on commercial e-matches. I'm using these for consumer fireworks displays, so I'll stick with the typical e-match blanks for now. But your alligator clip idea will be perfect for testing various compositions without having to waste entire e-matches! It's essential to be very regular in manufacture as the resistance of each igniter governs how fast each will function, if one is too slow it may not function because the current stops when the first bridgewire is broken.This is what I like about the j-tek's I tested. They continue to allow current even after ignition; perfect for wiring in series.
Arthur Posted July 18, 2023 Posted July 18, 2023 Wires.co.uk certainly sell nichrome wire in lots of useful gauges, www.wires.co.uk/acatalog/nc_bare.html , but having plain nichrome you need nichrome suitable (phosphoric acid based) flux. Skylighter.com sell a kit to make everything you want, but don't seem to sell the parts of the kit.
Richtee Posted July 18, 2023 Posted July 18, 2023 Wires.co.uk certainly sell nichrome wire in lots of useful gauges, www.wires.co.uk/acatalog/nc_bare.html , but having plain nichrome you need nichrome suitable (phosphoric acid based) flux. Skylighter.com sell a kit to make everything you want, but don't seem to sell the parts of the kit.Art... just double the lead-in by twisting the N wire to a “bridge” on the single strand. Alligator clips. Why ya soldering?
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