Who makes thier own igniters?

To the original post -

I'll use anything available as the initial heat source. For small motors, I tape a strip of blue propellant to the ignition source. Once the motor is up to an N, I use a single pyrodex pellet instead. At O, I use two pyrodex pellets. In these cases, ignition is typically about 3/4 second and it is a soft start. It is very reliable so far.

One can also use thermite but many use formulations which for all practical purposes detonate. I don't like the concussion inside the motor.

One wants to dump enough heat into the core so that a notable portion of the propellant surface is raised to above its ignition temperature. IMHO one does not want to dump enough heat in to raise the whole surface above ignition temperature - I want the igniter to burn out before the motor comes up to working pressure so that it doesn't add to the initial chamber pressure.

This is for ground level ignition of course. I presume at sufficient altitude it may be necessary to use an igniter design which will also aid in the initial pressurization of the motor in some cases. Besides, at lower pressures and temperatures one will need to dump a little extra heat in to assure ignition.

NASA published a paper on igniters years ago. One can find .pdf scans of it with a bit of search.

Gerald

I think I have the cheapest igniter possible. The wire is a spool of 2 conductor field telephone wire from the military, I think it's aluminum because it will not take solder. There's thousands of feet left on the spool, I got it for a dollar at at yard sale. Strip off 3/8 to 1/2" of insulation and give it 6 wraps of 40 gauge nicrome. I then coat it with CA and dip into crushed 4th of July sprinkler, the old style with a wire core and not the new ones with a reed core with some kind of flexable latex based compound. These things burn with a 1-1 1/2" ball of burning magensium that spits little flaming chunks. I made a wood mortar and an off-set pestel for crushing. I have a real good stasch of old sparklers, life time supply. They're a bit hard to find, I got mine at yard sales

karlbaum said:

This page explains basically how I make my igniters https://www.jacobsrocketry.com/aer/homemade_wire-wound_igniters.htm I use Pyrodex but grind it into a fine powder. I use ping pong balls and acetone for the binder.

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Karl, several sources say to use BP, and you mention you use Pyrodex instead. I'm curious as to why. It seems Pyrodex might be safer to work with (flammable rather than explosive). However, Pyrodex also has a higher ignition temperature. Perhaps I'm just overly cautious, but the idea of hand grinding 4f BP into a fine powder makes me a tad nervous.

Worsaer said:

... It seems Pyrodex might be safer to work with (flammable rather than explosive). However, Pyrodex also has a higher ignition temperature. Perhaps I'm just overly cautious, but the idea of hand grinding 4f BP into a fine powder makes me a tad nervous.

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The MSDS for the Pyrodex I was able to find uses potassium perchlorate (KClO4) as the oxidizer, which is a strong oxidizer. Chlorates in pyro compositions tend to be shock sensitive (e.g., burn on impact). In fact the MSDS (https://www.sciencelab.com/msds.php?msdsId=9924687) for KClO4 says to "avoid shock and friction". It also has potassium nitrate (KNO3) in the composition, which is another oxidizer though not as strong as KClO4, although I don't why they have both unless the KNO3 is there to cut the oxidizing power of the KClO4. Also, with KClO4-based pyro compositions, you are not to over coat them with anything containing sulfur, copper, or ammonia compounds. For this reason, it is NOT recommended to have BP and Pyrodex in contact with each other, since one of the components of BP is sulfur. Not saying that you or anyone else is doing this, I am just mentioning it as a safety precaution.

Therefore, I would feel more "comfortable" grinding BP (which can be successfully done, using non-sparking tools and working with very small amounts - think less than a gram) than I would Pyrodex, due to it's friction sensitivity. If you grind either, take precautions. Think small, very small.

Greg

Looking for 4F one time, I spoke to a guy that sold BP for 50 years or so. He claimed it only came in 1F or so back in the day. He started grinding it finer and screening it for his customers that shoot muzzle loaders. That was a large part of his business. He recommended I just get 2F and grind it to what I needed (4F he claimed was in short supply).

Can't say I can verify his story, but that was the old timer advice I was given in his store. Can't speak to his technique, how to do it safely, etc.

I used an 1 1/8th" drill bit I have and fitted a 1" dowel with a long cross handle for a pestel. All I did was use a 2x4 for the mortar. I still have it...somewhere...

Grinding dry BP or Pyrodex is dangerous, and the medical expenses you will incur if it goes off far outweigh any cost saving gained by rolling your own igniters.

Soluble nitrocellulose slurry is easy to make and use and more energetic as a pyrogen/binder than either BP or Pyrodex. It is used in many commercial e-matches and igniters and doesn't require grinding. If you don't want to learn pyrotechnic chemistry, buy a commercial non-regulated igniter dip mix and use it. These mixes are safer and work better than any homebrew BP/Pyrodex based igniter you'll come up with.

Bob

Thanks Bob - well said.

I use a ceramic mortise and pestle and grind about 0.25 g of BP at a time. Even if it does go off, that small amount won't touch the welding gloves and safety glasses. I've found that I seldom need more than that much ground up. I don't use BP for igniters, I have a formula that works much better and mix that instead. I can grind the ingredient without worry and wet it down after mixing the dry ingredients. It takes about 24 hours for it to dry enough to burn well.

dave carver said:

I think I have the cheapest igniter possible. The wire is a spool of 2 conductor field telephone wire from the military, I think it's aluminum because it will not take solder. There's thousands of feet left on the spool, I got it for a dollar at at yard sale. Strip off 3/8 to 1/2" of insulation and give it 6 wraps of 40 gauge nicrome. I then coat it with CA and dip into crushed 4th of July sprinkler, the old style with a wire core and not the new ones with a reed core with some kind of flexable latex based compound. These things burn with a 1-1 1/2" ball of burning magensium that spits little flaming chunks. I made a wood mortar and an off-set pestel for crushing. I have a real good stasch of old sparklers, life time supply. They're a bit hard to find, I got mine at yard sales

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What, do you use acetone to make it into a paste for dipping?

While we are on the subject..... my buddy bought a dip kit about 10 years ago that did not need the nichrome wire across to bridge the wires. Unfortunately one of the components dried up and requires MEK to soften it back up... MEK is no longer legal here in California.... anybody know of a commercial kit like this?


Jerome

JeromeK99 said:

While we are on the subject..... my buddy bought a dip kit about 10 years ago that did not need the nichrome wire across to bridge the wires. Unfortunately one of the components dried up and requires MEK to soften it back up... MEK is no longer legal here in California.... anybody know of a commercial kit like this?


Jerome

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Regarding the MEK question...

https://www.rocketryforum.com/showthread.php?59409-Where-s-MEK

Greg

JeromeK99 said:

While we are on the subject..... my buddy bought a dip kit about 10 years ago that did not need the nichrome wire across to bridge the wires. Unfortunately one of the components dried up and requires MEK to soften it back up... MEK is no longer legal here in California.... anybody know of a commercial kit like this?


Jerome

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Regarding the question about commercial igniter kits without a bridge wire, this is available but I don't have any personal experience with it:

https://www.electricmatch.com/hobbyists.html

Greg

hball55 said:

What, do you use acetone to make it into a paste for dipping?

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Nope, just wind the NiChrome on the exposed end of the two core, put CA on them and roll or dip into the powder. They dry real fast...

I use Potas nitrate, aluminum in nitrocellulose lacquer. Hot enough to light thermite. Used proportions from Propep

I've been making igniters for years now. Here is a video of my "Fire On The Bayou" formula. Guaranteed to light any motor! There is a four step proccess to make them. But it's easy. :grin:

[YOUTUBE]_WsdyJGX_UQ[/YOUTUBE]

BayouRat said:

I've been making igniters for years now. Here is a video of my "Fire On The Bayou" formula. Guaranteed to light any motor! There is a four step proccess to make them. But it's easy. :grin:

[YOUTUBE]_WsdyJGX_UQ[/YOUTUBE]

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How big is the igniter?

cavecentral said:

How big is the igniter?

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The one in the video is the same as a First Fire.

I've been pretty happy with Jimmy Yawn's Spectracide and Paper towel formula.

https://www.jamesyawn.net/ignitors/fusepaper/index.html

Easy to prepare the paper and store in a ziplock baggie, then make up ignitors on the field as needed.
No need to deal with 'hazardous' material like MEK, acetone, pyrogen mixes, etc...

Did you know Spectracide is 100% KNO3?

BayouRat said:

I've been making igniters for years now. Here is a video of my "Fire On The Bayou" formula. Guaranteed to light any motor! There is a four step proccess to make them. But it's easy. :grin:

[YOUTUBE]_WsdyJGX_UQ[/YOUTUBE]

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That's the same size as a FirstFire? Or is it lighting something else?

CarVac said:

That's the same size as a FirstFire? Or is it lighting something else?

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It's his igniter lighting thermite.

Greg

CarVac said:

That's the same size as a FirstFire? Or is it lighting something else?

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The actual igniter is the same size as a first fire. The igniter is the first to burn in the first few frames of the video. It ignites a motor starter grain for a Q motor. Then I had some scraps in the bottom and that's what really cooks off in the end.

brianc said:

I've been pretty happy with Jimmy Yawn's Spectracide and Paper towel formula.

https://www.jamesyawn.net/ignitors/fusepaper/index.html

Easy to prepare the paper and store in a ziplock baggie, then make up ignitors on the field as needed.
No need to deal with 'hazardous' material like MEK, acetone, pyrogen mixes, etc...

Did you know Spectracide is 100% KNO3?

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Spectracide? Bug Spray?

BayouRat said:

Spectracide? Bug Spray?

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Stump remover.

CarVac said:

Stump remover.

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But isint that in prill form. I've heard if you try and grind it turns to mush.
I use KNO3, AirFloat Charcoal, and Al. in my mix. I bought it a long time ago from some guy in a dark alley late one night. :wink:

BayouRat said:

But isint that in prill form. I've heard if you try and grind it turns to mush.
I use KNO3, AirFloat Charcoal, and Al. in my mix. I bought it a long time ago from some guy in a dark alley late one night. :wink:

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I've seen it in powder form.

what about the digestible Charcoal - plant fiber based ?

BayouRat said:

I bought it a long time ago from some guy in a dark alley late one night. :wink:

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Psssst.......Psssst......hey, need any more?


said in my best dark alley voice.:dark:

XrayLizard said:

what about the digestible Charcoal - plant fiber based ?

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If by that you mean activated charcoal, it is my understanding that it isn't used in pyro applications (i.e., does not perform as well as airfloat C).

Greg

GregGleason said:

If by that you mean activated charcoal, it is my understanding that it isn't used in pyro applications (i.e., does not perform as well as airfloat C).

Greg

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Yes activated. thanks for the reply.