EMatch Failure To Ignite

[MichiganJohn]

Wondering if anyone has experience with an entire 'batch' of commercial ematches not igniting, and if so what might be the cause? I was doing a ground test last week and two of the charges didn't fire. I verified it wasn't due to my ignition system, and then made up a couple fresh charges - which also didn't fire. Ultimately, I ended up test-firing ematches from other batches (with success) and went through 5 or 6 from this particular batch with no success. These are the standard orange wire with red plastic end cap variety - I've never had that happen before. Seems like it would have to be a manufacturing issue to have a 100% failure rate (?) Anyway, I'll be sacrificing at least one to test from every batch I buy going forward - lesson learned.

Edit: the issue was my ignition system not the ematches - see post #12 below.

 

[Handeman]

Where they open to begin with, or 1 Ohm before and open after?

I always test every match I use before flight to make sure they measure about 1 Ohm. I've had no failures at all with the orange wire ones. I've also never found one that wasn't about 1 Ohm either.

It does sound like you got a bad batch.

 

[tfish]

After checking their ohms..can you lite one with a regular match or cig lighter?

From ebay? Name of seller...recent purchase? ..for others to have a heads up..

Tony

 

[cerving]

MJG had a bad batch of FireWire ematches very early on in their production, they replaced them and there have not been any issues since. That's the only story I've ever heard of entire batches failing. I HAVE heard of and HAVE had some of the Chinese eBay ematches with spotty QC... I inspect every one and test them with an ohmmeter before I hook them up (most will read about 1 ohm give or take a few tenths).

 

[manixFan]

How did you verify it wasn’t your ignition system? In my personal experience, when I’ve had e-matches fail to fire it was not the e-match. If they test as good, they will fire. But I’ve not had the same experience with ignitors. I’ve had ignitors test good, but then fail to ignite the pyrogen.

Can you re-test the ematches that did not fire with a 9 volt battery across the leads?That’s always been my backup test of a failed match. If it fires, it may have been something else that caused the issue.

My concern is it is too easy sometimes to blame the wrong part of a system for a failure, which fails to diagnose the real issue.

Just food for thought.


Tony.

 

[ksaves2]

MJG had a bad batch of FireWire ematches very early on in their production, they replaced them and there have not been any issues since. That's the only story I've ever heard of entire batches failing. I HAVE heard of and HAVE had some of the Chinese eBay ematches with spotty QC... I inspect every one and test them with an ohmmeter before I hook them up (most will read about 1 ohm give or take a few tenths).

Give people the source of an ohm meter that can read that low. I had trouble finding mine years ago and doubt the seller is still in business. It's important the meter doesn't use much current or a good match will pop!

 

[Banzai88]

Give people the source of an ohm meter that can read that low. I had trouble finding mine years ago and doubt the seller is still in business. It's important the meter doesn't use much current or a good match will pop!

I mostly use a Fluke 77 I bought new more than 15 years ago, but even my $3 Harbor Freight throw away special that is in my range box gives the same results as far as ohms checking ematches.

Never had either meter set one off.

 

[Rocketclar]

MJG had a bad batch of FireWire ematches very early on in their production, they replaced them and there have not been any issues since. That's the only story I've ever heard of entire batches failing. I HAVE heard of and HAVE had some of the Chinese eBay ematches with spotty QC... I inspect every one and test them with an ohmmeter before I hook them up (most will read about 1 ohm give or take a few tenths).

I was one of those people quite a few years ago and yes I had 100% failure rate. MJG did replace them and told me that a vendor had sent them material that was out of spec. Those bad ones would test ok electrically, but just wouldn't fire. Orange ones are not MJGs. Contact the vendor and tell them the lot number that's on the box. I still test each with a VOM before I put it into my charge cannister and then afterwards to make sure I didn't break any connections pulling the wires through. Another final check is when the altimeters are powered up and beeping out continuity correctly.
(Edited since OP said Orange ones....)

 

[manixFan]

Give people the source of an ohm meter that can read that low. I had trouble finding mine years ago and doubt the seller is still in business. It's important the meter doesn't use much current or a good match will pop!

I’ve had issues with auto-ranging multimeters taking a while to settle when measuring ematches, but other than that even those can work well. I keep a 1 ohm +/- 5% resistor in my range box that I can use to test my multimeter if it seems wonky.

Any multimeter that that fires an ematch while checking resistance should be taken out of service. No multimeter should use that much current for resistance.


Tony

 

[cwbullet]

You can failures with ematches and igniters when if the most skilled solderer and dipper makes them. It does not matter if they are commercial.

 

[Handeman]

I use an old Radio Shack analog VOM I bought about 1975. I like the analog because the needle movement will tell you if it's slightly above or below 1 ohm. My newer, more expensive digital multimeter on has a resolution of 1 ohm so it's either 0, 1 or 2 ohms when measuring an ematch.

A Milliohm-Meter would be the most accurate, but a low end one will run about $150 and high end >$1000.

 

[MichiganJohn]

Thanks for all responses. I ran through these suggestions and discovered the fault was with my ignition system - which surprised me because I tested the system output and the batteries that power it, and it ignites all other ematches except from this particular batch.

But each ematch from the 'bad batch' ignited when I connected to a fresh 9 volt. Pretty rookie mistake on my part not to play out the diagnosis process further, but once I thought the ignition system was ok I didn't try any other methods.

I test each ematch before they get wired up for service and I've never had a bad one before - I feel a little better knowing it was faulty equipment on my end and not a faulty manufacturing process to be wary of.

Thanks for all the comments and help.

 

[MichiganJohn]

How did you verify it wasn’t your ignition system? In my personal experience, when I’ve had e-matches fail to fire it was not the e-match. If they test as good, they will fire. But I’ve not had the same experience with ignitors. I’ve had ignitors test good, but then fail to ignite the pyrogen.

Can you re-test the ematches that did not fire with a 9 volt battery across the leads?That’s always been my backup test of a failed match. If it fires, it may have been something else that caused the issue.

Thanks Tony - you were right.

 

[Orestes Mayo]

MJG had a bad batch of FireWire ematches very early on in their production, they replaced them and there have not been any issues since. That's the only story I've ever heard of entire batches failing. I HAVE heard of and HAVE had some of the Chinese eBay ematches with spotty QC... I inspect every one and test them with an ohmmeter before I hook them up (most will read about 1 ohm give or take a few tenths).

What size of ematch would be used for LP vs MP vs HP motors?

 

[David_Stack]

What size of ematch would be used for LP vs MP vs HP motors?

In general eMatches are not used for motor ignition, igniters are. eMatches are used to fire deployment charges (black powder primarily) in response to voltage applied from an altimeter.

Igniters/lighters example: https://wildmanrocketry.com/collections/wildman-brand-lighters

eMatch: https://electricmatch.com/rocketry/see/36/6/mjg-firewire-initiater

 

[Orestes Mayo]

In general eMatches are not used for motor ignition, igniters are. eMatches are used to fire deployment charges (black powder primarily) in response to voltage applied from an altimeter.

Igniters/lighters example: https://wildmanrocketry.com/collections/wildman-brand-lighters

eMatch: https://electricmatch.com/rocketry/see/36/6/mjg-firewire-initiater

Thank you. Interesting. I had been told its a good alt to Estes ignitors.

 

[Art Upton]

Thank you. Interesting. I had been told its a good alt to Estes ignitors.

Ematches are an alternative to Estes Ignitors, especially for Black Powder clusters.

 

[Orestes Mayo]

Ematches are an alternative to Estes Ignitors, especially for Black Powder clusters.

Oh ok. That is what I had been told but when I went to the site, not exactly sure which to get. Would you happen to know? Thanks.

 

[Art Upton]

Oh ok. That is what I had been told but when I went to the site, not exactly sure which to get. Would you happen to know? Thanks.

BP starters , this is what I bought at Chris's Rocket Supply:

https://electricmatch.com/rocketry/see/23/6/bp-rocket-starters

 

[Donnager]

In general eMatches are not used for motor ignition, igniters are. eMatches are used to fire deployment charges (black powder primarily) in response to voltage applied from an altimeter.

Igniters/lighters example: https://wildmanrocketry.com/collections/wildman-brand-lighters

eMatch: https://electricmatch.com/rocketry/see/36/6/mjg-firewire-initiater

Don't sell yourself short. I've launched essentially every high power of mine with e-matches over the last three years.

Just dope the e-match. They will be more reliable than an Aerotech igniter.

 

[Hobie1dog]

Thanks for making this topic as I learned something about e-matches and testing them

 

[cwbullet]

I mostly use a Fluke 77 I bought new more than 15 years ago, but even my $3 Harbor Freight throw away special that is in my range box gives the same results as far as ohms checking ematches.

Never had either meter set one off.

I would strongly recommend a good one such as Fluke. Harbor Freight is good for some things, and this is not one of them.