Diy E-match or igniter

[AtomicStorm]

Ok, so i know everyone at one point has either thought of or has made their own custom diy e-match or igniter. Post a picture of yours and give a sentence or 2 explaining it. Most points for easiest and cheapest design.

 

[Rocketjunkie]

You can get commercial, unregulated ematches at https://electricmatch.com/rocketry/see/36/6/mjg-firewire-initiater
Not worth the reliability issues of homemade as the commercial ones are less than $1 each.

 

[Rocketjunkie]

I've been making starters for my long 18 mm D grain motors. 30 gauge wire wrapping wire for leads, 50 micron tungsten bridge wire and Quickburst pyrogen. The picture shows one inserted in a Q-Jet B4-4 with another showing the head. These will fire on about 1 amp, resistance is .9 +- .3 ohms.

 

[AtomicStorm]

What do you use to hold it in place?

 

[prfesser]

Probably the least expensive type of starter is the match-head starter:

Often can be made from the scrap box. A fine nichrome bridge wire has each end wound around copper leads. (thin copper strands from fine stranded wire will work too). The bridge wire is inserted in a small notch in the top of the match head, and the whole thing is taped together.

For 18mm BP motors the edges of the match head may need to be scraped off. For larger motors a strip of easily-ignited composite propellant is taped to the match head.

Best -- Terry

 

[prfesser]

You can get commercial, unregulated ematches at https://electricmatch.com/rocketry/see/36/6/mjg-firewire-initiater
Not worth the reliability issues of homemade as the commercial ones are less than $1 each.

I can't agree enough with this sentiment, at least for ematches that are to be used for ejection charges. Not worth the risk of a failed ejection and a busted rocket. For ematches used as motor starters, making them at home is okay BUT... the homemade ones usually use a two-step dip: a tiny amount of highly sensitive primer for initial ignition, topped with a less-sensitive mixture. The primer---which does not burn, it explodes!---is dangerous to make and is never to be stored.

Edit: FWIW I've used commercial ematches to ignite the last couple dozen two-grain 38 mm research motors I've tested. Only one motor did not ignite.

 

[cwbullet]

I can't agree enough with this sentiment, at least for ematches that are to be used for ejection charges. Not worth the risk of a failed ejection and a busted rocket. For ematches used as motor starters, making them at home is okay BUT... the homemade ones usually use a two-step dip: a tiny amount of highly sensitive primer for initial ignition, topped with a less-sensitive mixture. The primer---which does not burn, it explodes!---is dangerous to make and is never to be stored.

Edit: FWIW I've used commercial ematches to ignite the last couple dozen two-grain 38 mm research motors I've tested. Only one motor did not ignite.

I have to agree on them not being worth the risk for ejection charges. I have made matches and had 100% success so far, but it only takes one failure to make it not worth it. I use them only as motor lighters.

 

[UhClem]

The primer---which does not burn, it explodes!---is dangerous to make and is never to be stored.

I remember reading a document which described the NASA Standard Initiator. It used ZPP (Zirconium Potassium Perchlorate) mixed in tiny lots with great care and applied with a toothpick.

Not to mention that anything with a sensitive primary explosive, let alone a typical pyrogen like BKNO3, will have ATF entanglements. Even if you make them yourself.

 

[ksaves2]

DON'T, DON'T DON'T I REPEAT DON'T try to make ematches for rocketry. The quality control on the bare blanks/heads sold absolutely stink. One has to solder the lead wires to them fastidiously and not gunk the solder on to cause a short. Two different dips have to be made with one component being especially sensitive to friction. Get some on the threads of the little glass bottle you're using and if you try to unscrew it the next day, it could go BOOM in your face. I was aware of this before I worked with it and treated it accordingly. One also needs an Ohm meter to weed out the matches with high resistance.

I resorted to making my own blanks wrapping nichrome wire around PC board, soldering and I had an appropriate shear to cut them. Had to check every single chip for pieces of copper clad that fractured causing a potential short. Sand paper usually cleaned them up.

I learned to make just enough of the components to use up in one sitting. After 5 years, I got good at it but with the availability of good commercial matches I stopped as it just isn't worth the labor. Oh, for fun I used to hit the head of the dried toothpick
I used to mix the first pyrogen (with a welder's face shield with a clear window for protection) and it would give a loud pop.

At the time I was doing it, we (rocketry) was in jeopardy of not being able to get reliable ematches (required LEUP otherwise) hence that was my impetus to attempt to learn the art. Learn it I did but boy was it a pain in the arse. About the time I mastered it, the easily obtainable matches came out and I IMMEDIATELY abandoned making my own.

Want to mess with making 12V engine "starters", "lighters" or whatever they call them? That's manageable and relatively safe for a neophyte to attempt. Get a kit and follow the instructions is the easiest for someone new at this. Can research some of the pyrogens out there and most (not all) are pretty safe. The unsafe formulas are clearly labelled as such and just about impossible to get the components for those anyways. I checked and many of the components cost too much for me to consider. Plus I didn't like the idea of getting killed by a "starter", "lighter" or igniter.
Kurt

 

[dvdsnyd]

I don't want to be redundant here, but I'm not sure what your experience level is.
Typically, in the rocketry community, e-matches are used to deploy parachutes instead of the ejection charge supplied with the motor. (Some larger high powered motors don't have ejection charges)
I agree with the others that have pointed it out, do not make these. It isn't worth it.
You can buy commercial ones, ATF regulation free from MJG Technologies, specifically the MJG Firewire initiator.

Igniters, or starters are an entirely different situation. These are used to ignite motors on the ground - not talking about 2 stage flights here.
Reliability is much less of a concern. If the igniter doesn't work, you go out and replace it after the rack has been gone through by the LCO.
Many motor manufacturers provide them with the motor. However, some don't.
Quickburst makes a kit you can purchase to make your own igniters called quickdip. You'll need some wire too, I believe he has starter kits with everything.
Great for those Loki motors as well as to have some spares on hand.
Quickdip

 

[prfesser]

As for motor starters/initiators, the most common type is wind-and-dip. Some say this takes too much work/time/something else. My view: I can make enough starters for a season's flying and testing in a single evening. And as (I think) I've said before, what is a hobby but a way to waste time and money? The product is happiness.....and I do enjoy making these.

Anyway, these should be fairly clear:


These images show so-called "shooting wire", but CAT-5 or whatever style of network cable (twisted pairs) is handy works fine. This batch used 32 ga nichrome but 36 ga has been quite successful. Some workers solder the nichrome-copper connections. My experience has been that if at least eight or ten tight turns are used to anchor each end of the nichrome, the starter is good for a year, possibly longer. I start with a length of nichrome a meter or so long, and snip off the end with scissors after the second winding.

Use your favorite dip. We don't discuss formulations except in the Research forum but a search of the web should land a dozen or so dip-mixtures.

Best -- Terry

 

[cwbullet]

DON'T, DON'T DON'T I REPEAT DON'T try to make ematches for rocketry.

Just to correct this statement. Do not make e-matches to air starts, staging, or dual deployment. They are fine motor lighters. I got one heck of deal on blanks from Skylighter and they work well at lighting motor with a second dip.

 

[AtomicStorm]

Just to be clear, these are just for starters on the ground and maybe used for other things that go boom.

 

[cwbullet]

Just to be clear, these are just for starters on the ground and maybe used for other things that go boom.

Hopefully, nothing goes booM.

 

[AtomicStorm]

Hopefully, nothing goes booM.

Its ok i have rocket, airplane and shooting/explosive days. As long as it falls on the right day it should be ok.

 

[Ez2cDave]

Kurt,

Isn't the purpose of using the fine gauge Bridge Wire to create high resistance, so that the wire will glow red hot and ignite the chemicals of the igniter ?

Dave F.

 

[Ez2cDave]

DON'T, DON'T DON'T I REPEAT DON'T try to make ematches for rocketry.

Two different dips have to be made with one component being especially sensitive to friction. Get some on the threads of the little glass bottle you're using and if you try to unscrew it the next day, it could go BOOM in your face.

Oh, for fun I used to hit the head of the dried toothpick I used to mix the first pyrogen (with a welder's face shield with a clear window for protection) and it would give a loud pop.

Plus I didn't like the idea of getting killed by a "starter", "lighter" or igniter.

Kurt

Kurt,

Have you ever personally witnessed, or have a link to information about, a container of pyrogen dip ( for rocketry ) exploding when the lid was unscrewed ?

What pyrogen formula were you using that could be set of with a blow from a hammer ?

What information do you have about people being killed by a rocketry igniter ?

Please provide links . . . Thanks !

Dave F.

 

[ksaves2]

Just to correct this statement. Do not make e-matches to air starts, staging, or dual deployment. They are fine motor lighters. I got one heck of deal on blanks from Skylighter and they work well at lighting motor with a second dip.

Well I have to qualify I ordered commercial blanks many years ago and they were not very good. Did an ematch kit too and still the reliability stunk. Perhaps that has changed. Yes for airstarts and staging, an augmented ematch initiated igniter is needed but discussing how to do that is outside the realm of this thread. ie. No formulas can be discussed. Some of the thermites out there are pretty scary. The standard ones have a high energy of activation and are relatively safe but some of the doctored ones can be started with an ematch. Holy molee, I came to the conclusion to just make a teeny tiny bit of that stuff for experimenting and not keep it mixed and lying around.
I haven't actually done or flown an airstart or staged APCP but when I was working on my "made from scratch" ematches which I then augmented to light a motor, I was trying to be ready to do so. I did a lot of ground testing as I mixed my own motors and had some loose grains around I could do ignition tests on. Have been on hiatus for awhile now.
I still don't think it's smart to make one's own ematches. Too many things can go wrong. Using an augmented ematch to launch a rocket is no big deal. If it fails, go out and replace the igniter. If it fails with an airstart or staging, might have a different effect. I'd like to pick one's brain one on one on how they do it someday at a launch. Mano o' mano would be the way to do that interaction.

Kurt

 

[ksaves2]

Kurt,

Isn't the purpose of using the fine gauge Bridge Wire to create high resistance, so that the wire will glow red hot and ignite the chemicals of the igniter ?

Dave F.

No, take an ohm meter that can measure low resistances and test the commercial ematches out there. They're all around 1 to 2 ohms. Any higher and it will take more current from the altimeter to start the pyrogen.
When I'd get some of my matches that read 8 ohms on the meter, I'd use them for 12V starters with augmentation. As mentioned before, I don't make matches anymore.
That's another thing. If one is going to try to make ematches (and I've said it's not worth it) they need to be able to get an ohm meter that they can test their matches with.
Heck, I test my commercial matches with my ohm meter and I rarely see any one above 2 ohms.

Kurt

 

[cwbullet]

Well I have to qualify I ordered commercial blanks many years ago and they were not very good. Did an ematch kit too and still the reliability stunk. Perhaps that has changed. Yes for airstarts and staging, an augmented ematch initiated igniter is needed but discussing how to do that is outside the realm of this thread. ie. No formulas can be discussed. Some of the thermites out there are pretty scary. The standard ones have a high energy of activation and are relatively safe but some of the doctored ones can be started with an ematch. Holy molee, I came to the conclusion to just make a teeny tiny bit of that stuff for experimenting and not keep it mixed and lying around.
I haven't actually done or flown an airstart or staged APCP but when I was working on my "made from scratch" ematches which I then augmented to light a motor, I was trying to be ready to do so. I did a lot of ground testing as I mixed my own motors and had some loose grains around I could do ignition tests on. Have been on hiatus for awhile now.
I still don't think it's smart to make one's own ematches. Too many things can go wrong. Using an augmented ematch to launch a rocket is no big deal. If it fails, go out and replace the igniter. If it fails with an airstart or staging, might have a different effect. I'd like to pick one's brain one on one on how they do it someday at a launch. Mano o' mano would be the way to do that interaction.

Kurt

I would never use a comercial made blank for anything but a motor lighter. I have had great success with my dips in both commercial and homemade blanks. I did it just to experiment. The deal I got on blanks was $18 per 100. I could not pass it up. I bought 500. I use them for ground testing and motor lighters. I have had less than a handful fail.

 

[AtomicStorm]

Good to see and hear what everyone is using. I have some ideas now for a rainy day

 

[Jim Green]

Kurt,

Have you ever personally witnessed, or have a link to information about, a container of pyrogen dip ( for rocketry ) exploding when the lid was unscrewed ?

What pyrogen formula were you using that could be set of with a blow from a hammer ?

What information do you have about people being killed by a rocketry igniter ?

Please provide links . . . Thanks !

Dave F.

The extremely sensitive formulas for a first pyrogen used on blank ematch heads use potassium chlorate which is well known for causing accidents in the fireworks industry. A search for "potassium chlorate sensitivity" will yield a number of you tube videos and articles attesting to its sensitivity to friction or shock when mixed with certain chemicals.

 

[ksaves2]

Kurt,

Have you ever personally witnessed, or have a link to information about, a container of pyrogen dip ( for rocketry ) exploding when the lid was unscrewed ?

What pyrogen formula were you using that could be set of with a blow from a hammer ?

What information do you have about people being killed by a rocketry igniter ?

Please provide links . . . Thanks !

Dave F.

Dave no,

We're talking about two different things here. Pyrogen for high current motor igniters are not an issue here. I wipe the threads of the bottle and the inside of a cap and will store it for a time with impunity.

The first fire pyrogen for an EMATCH is very friction and shock sensitive. I think Dr. Terry McCreary and other sources have commented on that. There is a second pyrogen (in a classical ematch) that goes over the first dip. That one is not so shock sensitive. Unscrewing the cap of a first fire ematch dip that has dried on the glass or plastic threads and metal cap could provide enough friction to ignite the dried material on the threads and cap.
Whether or not the liquid in the bottle would go up I don't know.
Again, I am talking about ematch first dip not motor igniter dip.
Storing mixed motor dip in a liquid state for a time is safely possible with care.

Pyrogens for motor starters and ematches are two different animals.

Again, the pyrogen for motor starters/igniters is not all that shock sensitive. One wants a motor starter to flare, create high heat and not go bang. An ematch that "pops" works fine starting 4F charges although I did have a batch that flared nicely in deployment altimeter testing mode.

I believe the reason one doesn't hear horror stories of ematch mixing mishaps is there are not very many out there who make them from scratch. Chuck above mentions he's made them. Motor starters/igniters are a different story in that many folks can make them safely as the pyrogens (except for a few) are readily workable and safe for a hobbyist to make. More storable too.

Is that clearer now? Ematches and motor starters are two different animals here. No, I've never heard of anyone having a bottle of first fire EMATCH pyrogen go off in their face on one hand. On the other hand I'd expect they'd be too embarrassed to mention that online. As I mentioned, I used a hammer and lightly tapping the dried mixing toothpick results in a pop.

I will confess a Stupidhead moment as I one time had a Testor's paint bottle of dried out first fire EMATCH pyrogen and pondered what to do to dispose of it. I have a large woods behind my house and collect dead branches to burn to keep the area tidy. I still have to look out there and my wife (now deceased) wanted the area to be kept clean. I agreed. I did a bonfire of tree branches and nonchalantly tossed the bottle of first fire EMATCH pyrogen in. After a few seconds there was a WHAM! and the bottle fragments come flying out fortunately out toward the woods and not towards me! I was smart enough to run away after I tossed the bottle in and was a fair distance away.
The next small bottle of dried out first fire pyrogen I had I stuffed a standard rocket motor igniter in and buried it into the ground with a large rock on top of it. Pushed the button on my 12V launch system and nary a pop. Dug it up and disposed of the glass fragments. One gets smarter with experience.

Kurt Savegnago

 

[ksaves2]

The extremely sensitive formulas for a first pyrogen used on blank ematch heads use potassium chlorate which is well known for causing accidents in the fireworks industry. A search for "potassium chlorate sensitivity" will yield a number of you tube videos and articles attesting to its sensitivity to friction or shock when mixed with certain chemicals.

That's partially correct but we can't discuss recipes here. There's more to it than that. You're right when you say "mixed with certain chemicals". Bottom line is buy the commercial ematches and call it good. Kurt

 

[Ez2cDave]

Dave no,

We're talking about two different things here. Pyrogen for high current motor igniters are not an issue here. I wipe the threads of the bottle and the inside of a cap and will store it for a time with impunity.

The first fire pyrogen for an EMATCH is very friction and shock sensitive. I think Dr. Terry McCreary and other sources have commented on that. There is a second pyrogen (in a classical ematch) that goes over the first dip. That one is not so shock sensitive. Unscrewing the cap of a first fire ematch dip that has dried on the glass or plastic threads and metal cap could provide enough friction to ignite the dried material on the threads and cap.
Whether or not the liquid in the bottle would go up I don't know.
Again, I am talking about ematch first dip not motor igniter dip.
Storing mixed motor dip in a liquid state for a time is safely possible with care.

Pyrogens for motor starters and ematches are two different animals.

Again, the pyrogen for motor starters/igniters is not all that shock sensitive. One wants a motor starter to flare, create high heat and not go bang. An ematch that "pops" works fine starting 4F charges although I did have a batch that flared nicely in deployment altimeter testing mode.

I believe the reason one doesn't hear horror stories of ematch mixing mishaps is there are not very many out there who make them from scratch. Chuck above mentions he's made them. Motor starters/igniters are a different story in that many folks can make them safely as the pyrogens (except for a few) are readily workable and safe for a hobbyist to make. More storable too.

Is that clearer now? Ematches and motor starters are two different animals here. No, I've never heard of anyone having a bottle of first fire EMATCH pyrogen go off in their face on one hand. On the other hand I'd expect they'd be too embarrassed to mention that online. As I mentioned, I used a hammer and lightly tapping the dried mixing toothpick results in a pop.

I will confess a Stupidhead moment as I one time had a Testor's paint bottle of dried out first fire EMATCH pyrogen and pondered what to do to dispose of it. I have a large woods behind my house and collect dead branches to burn to keep the area tidy. I still have to look out there and my wife (now deceased) wanted the area to be kept clean. I agreed. I did a bonfire of tree branches and nonchalantly tossed the bottle of first fire EMATCH pyrogen in. After a few seconds there was a WHAM! and the bottle fragments come flying out fortunately out toward the woods and not towards me! I was smart enough to run away after I tossed the bottle in and was a fair distance away.
The next small bottle of dried out first fire pyrogen I had I stuffed a standard rocket motor igniter in and buried it into the ground with a large rock on top of it. Pushed the button on my 12V launch system and nary a pop. Dug it up and disposed of the glass fragments. One gets smarter with experience.

Kurt Savegnago

Kurt,

Thanks for clarifying that !

Dave F.

 

[prfesser]

The first fire pyrogen for an EMATCH is very friction and shock sensitive. I think Dr. Terry McCreary and other sources have commented on that. There is a second pyrogen (in a classical ematch) that goes over the first dip. That one is not so shock sensitive. Unscrewing the cap of a first fire ematch dip that has dried on the glass or plastic threads and metal cap could provide enough friction to ignite the dried material on the threads and cap.

FWIW re. a conversation I had with a well-known author of pyrotechnic information, "could provide" may be edited to "has provided". Highly sensitive primer mixture + plastic bottle + friction of unscrewing = mangled hand. "After" photo of the of the bottle was provided. Didn't see pix of the hand. Probably a good thing.

Terry

 

[SharkWhisperer]

Just to correct this statement. Do not make e-matches to air starts, staging, or dual deployment. They are fine motor lighters. I got one heck of deal on blanks from Skylighter and they work well at lighting motor with a second dip.

I'm surprised you got a deal on anything from Skylighter. They are notoriously overpriced on every single fireworking chem that they sell. Selection? Yes. But 90% of the chems they sell are available elsewhere, generally for half of Skylighter's ridiculous price. $29 per pound of Indian flake Al? Ridiculous. Costs $10 at fireworkscookbook.com. Milled potassium nitrate at $9/pound? Ridiculous. Costs 4$ elsewhere. $3 for granular if you're not too lazy to grind it yourself; 1$ if granular and in bulk. Crummy commercial hardwood airfloat charcoal at $7/pound? Ridiculous. $3 everywhere else in small quantity. 20 feet of visco fuse (any speed desired) for $15? Unmitigated robbery. Everywhere else it is $5 (up from $4 last year). Could go on an on and on....through their entire catalog. Which is why it's known as SkyRobber in the fireworking community.

 

[SharkWhisperer]

FWIW re. a conversation I had with a well-known author of pyrotechnic information, "could provide" may be edited to "has provided". Highly sensitive primer mixture + plastic bottle + friction of unscrewing = mangled hand. "After" photo of the of the bottle was provided. Didn't see pix of the hand. Probably a good thing.

Terry

You simply do not store completed friction sensitive comps in screwcap jars. Ever. It's fine to use a plastic bottle for mixing slurrys for dipping that are relatively passivated in suspension (even in a flammable solvent), bur avoid screwcaps. Dried comp on the threads and a little friction are not a good combination. And glass containers of any type. Storage is unwise when it is such a simple thing to quickly whip up a new batch of most any pyrogen formulation that you might employ, including expensive kit components if you weigh and use only part of a kit at one time. But unfortunately many people ignore those basic safety tidbits, to their own detriment.

And for anybody thinking to experiment with pyrogens for the first time, even if you have a decent chemistry background (recommended), it is absolutely essential to know which chemicals simply do not play nice with others (think chlorates + sulfur in any form, as one example...).

 

[Rocketjunkie]

What do you use to hold it in place?

For rockets using engine hooks (up to mid D), I just put it under the hook against the rear of the motor. Larger motors are longer, up to 12" for a full F. Those get a tape thrust ring and friction fit. If you have research access, I have a detailed thread https://www.rocketryforum.com/threads/18-mm-motors.158722/

 

[ksaves2]

You simply do not store completed friction sensitive comps in screwcap jars. Ever. It's fine to use a plastic bottle for mixing slurrys for dipping that are relatively passivated in suspension (even in a flammable solvent), bur avoid screwcaps. Dried comp on the threads and a little friction are not a good combination. And glass containers of any type. Storage is unwise when it is such a simple thing to quickly whip up a new batch of most any pyrogen formulation that you might employ, including expensive kit components if you weigh and use only part of a kit at one time. But unfortunately many people ignore those basic safety tidbits, to their own detriment.

And for anybody thinking to experiment with pyrogens for the first time, even if you have a decent chemistry background (recommended), it is absolutely essential to know which chemicals simply do not play nice with others (think chlorates + sulfur in any form, as one example...).

Ditto,

I did a cursory look up of ematch comps now and they are a bit harder to find on the web than they were 15 years ago. Fine by me. Better to buy the available ematches than try to make them. A real pita as I’ve said to do safely.

Motor starter pyrogens are ok to store for a time but before sealing, lids and threads should be fastidiously wiped. The risk of ignition is less than a first fire dip for an ematch. That stuff is extremely friction sensitive as I’ve mentioned taking a hammer to the toothpick that had dried ematch first fire dip on it. I could get a pretty loud bang out of it.
I don’t make ematches anymore and quit some years ago when the commercial ones were more available. I haven’t looked back as it’s not worth my or anyone’s time to do it with the options to buy out there

Kurt