Igniters stored IN black powder - OK to use?

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Kelly

Usually remembers to get the pointy end up
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Sometimes I make up ejection charges (cheap chinese igniter, in a centrifuge tube with blackpowder) and don't get a chance to use it right away. I have some of these that have been stored like this (mostly in a dessicated storage bin) for a year or more. Is there any issue with using these? I'm concerned that maybe the power has corroded the wire or connections on the ematch, and it won't be as reliable.
 
Sometimes I make up ejection charges (cheap chinese igniter, in a centrifuge tube with blackpowder) and don't get a chance to use it right away. I have some of these that have been stored like this (mostly in a dessicated storage bin) for a year or more. Is there any issue with using these? I'm concerned that maybe the power has corroded the wire or connections on the ematch, and it won't be as reliable.
Fire a large sample and find out. I would also be concerned about having an igniter sitting in a charge for a long period of time. I have seen people store made up charges and have them fail but I can’t specifically why say it happened. I wouldn’t do it though.
 
I always aim to be a little extra cautious with making sure my rocket won't end up a lawn dart. Igniter + BP is one of the cheapest parts of the launch and I think it's cheap insurance to replace them rather then rely on something I don't have 100% faith in.

When I have leftover charges that been sitting around for 6+ months, I'll use them for deployment tests but generally avoid using them for flights. I have also removed the BP and re-used igniters for lighting the motor where a failed igniter just means another walk out to the launch pad.

The possible interaction between the BP and the igniter is what concerns me. Cheap insurance to replace for my piece of mind.

cheers - mark
 
I pre-assemble my vials with igniters hot glued in, but only fill them with the pre-measured BP just prior to flight at the site. If they don't get used on the day I empty the BP from them. I don't store them with BP in them as it's an unnecessary risk.
 
Sometimes I make up ejection charges (cheap chinese igniter, in a centrifuge tube with blackpowder) and don't get a chance to use it right away. I have some of these that have been stored like this (mostly in a dessicated storage bin) for a year or more. Is there any issue with using these? I'm concerned that maybe the power has corroded the wire or connections on the ematch, and it won't be as reliable.
Hello Kelly – I had a similar question about a month ago -- had 4 charge wells with 4F BP and ignitors inserted and taped "shut" - had put this AvBay in an explosion proof container but then forgot about this AvBay for 6 months. I tested one and it was fine -- and then launched with all 4 (new and 3 "6-month old") charges going-off perfectly. This is not how I'd plan to do things in the future but nice to know that the BP does not seem to attack / deteriorate the igniters. But as others have said, this is about the least expensive mission-critical item involved with a flight and probably best to fill charge wells as close to launch as feasible. Stephen on Wednesday 29 May 2024
 
For commercial ematches it's unlikely that there is any interaction between the BP and the bridge wire, as the latter is buried inside the match composition(s). The BP might corrode the copper lead wire a bit but I seriously doubt that it would be enough to worry about. But for future work I'd suggest filling with BP at the field. Ematches have been known to ignite spontaneously (not often, or they wouldn't be used in fireworks displays), possibly from static discharge. Ematch alone is a pop. Ematch plus BP might exceed that by a fair piece.
 
Does anyone know if the metal GOEX BP cans are coated internally? it doesn't look like it, and I have one that has 20 year old 4F BP in it, and inside the steel can I don't see any signs of rust or corrosion.

But, as others have said, it's best to fill in the field right before use.
 
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