How to make your own *reliable* E-matches

[Macgyver]

You will need the following materials:

1. Good quality blackpowder, 8 grams
2. Iron(III)Oxide, 0.2 grams
3. Zirconium, 0.8 grams
4. Nitrocotton, low nitrated ~1.0g
5. Acetone
6. Nichrome wire or Kanthal wire, smallest diameter you can find.

First prepare as many igniters that you wish to make by cutting about 20cm of telephone wire (the old style that has two leads close to each other) for each igniter.

Remove the insulation from the wires in one end and wrap the nichrome/kanthal wire between the wires, then fold the outer part of the naked wire over the wrapped part and press firmly with a pair of pliers.

Now it's time to prepare the chemical mixture to dip the e-matches in:

Start by weighting up the required amount of Zirconium and set it to dry (Zirconium is always stored underwater as dry fine mesh zirconium may self ignite when exposed to air), and as the zirconium is wet, take a bit more than 0.8g keeping in mind that it also contains water until dried.

Mix the blackpowder and iron oxide and wait for the zirconium to dry. Zirconium is very sensitive to static electricity that might be good to keep in mind.

Add the zirconium to the blackpowder/iron oxide mix.

Mix the nitrocotton with just enough acetone to make a sticky paste, and then pour the blackpowder/iron oxide/zirconium mix into it. Add more acetone, but no more than just whats needed to make it into a sticky paste again. If you accidentally add too much acetone, let it sit for a while and the excess will evaporate.

Dip the wires you prepared earlier in the mixture and make sure each one gets a decent amount of the composition, and set aside to dry.

The secret of the reliability of these igniters is the Zirconium, it burns very hot and significantly lowers the ignition temperature. Depending on what nichrome/kanthal wire gauge you choosed as little as 3V might be enough to get ignition.

Have a nice X-mas and New Year, and remember be careful and stay safe.

[nbk2000]

Pure zirconium powder may be hard for a lot of people to get, but everyone can get lighter flints, which are made of similar pyrotechnic metals.

Weighing out the required amount of flints, and carefully rotating the striker to powder it over a dish of water, would be very OTC. :)

Nitrocellulose = Ping Pong balls.

Nichrome wire = superfine steelwool

[Dibs]

I remember reading a site (address forgotten) regarding simple e-matches.

If I remember correctly, computer IDE ribbon cables were used (the cable that connects hard-drives and CD/DVD drives), because they are easy to get and the wires end up being at an optimum distance apart for the match mixture...

The IDE cable is split into pairs (the cable is a ribbon of 40 wires ie: 20 pairs) and the ends are stripped. A mixture of nitrocellulose and acetone is made that is thick enough that it should stick to the wires. Also pure graphite powder - commonly sold as a dry lubricant - is added to make the mixture electrically conductive. The wires are then dipped into the mix and allowed to dry.

I have not yet tried this myself, and I have doubts whether the graphite will work as intended... even so the mix can be used to coat a nichrome wire.
Thoughts?

Also one question... ping-pong balls as nitrocellulose!? You mean the balls can be grounded and used as a source of cellulose, yeah?

[stupid939]

Dibs - I believe you saw Brainfever's site (here (http://www.geocities.com/brainfevert/ematch.html)) and these were bridgeless ematches.

Mac - This is a method pretty close to yours. He uses fine copper wire instead of nichrome (steel wool would work too) and his site has pictures.

http://www.jamesyawn.com/ignitors/bridgewire/index.html

If you go to his home page he has other igniters too.

[sprocket]

I've been testing these bridgeless igniters for about two weeks now with great success. The graphite/NC mix will heat up very quickly when current flows through it, igniting the coating pyrogen almost instantly. The thinner the graphite/NC-coating the better (faster) ignition.

Using flat cables might be a really good idea. So far I've been using TP cables, and preparing these twisted pairs has been the most time consuming part. Are the conductors in flat cables typically single stranded?

All in all I must say bridgeless igniters are a wonderful thing. They're so quick and easy to make, and so far every single one of them has worked. I've fired over 100 to this date, so that's a fairly good performance record.

Ping-Pong balls are made of a plastic called celluloid. That's low nitrated cellulose with some additives.

[dumbrella]

In regards to the first type of ignitors shown in this thread, how does the Zirconium content effect the impact and friction sensitivity of the pyrogen?

I have heard of commercial ignitors igniting when being stepped on or otherwise mis-handled, and was wondering how these stand up. Also, if i was to replace the Zirconium with lighter flints, as NBK suggests, would this make them more or less sensitive?

Thanks in advance for your help :)

[deadman]

For NC lacquer via ping pong balls. Just dissolve the ping pong balls in acetone. It is said, that something a little more free flowing than Elmer's White Glue works well in most applications. Or you can try to figure out 10%, but if it works it works.

Instead of ping pong balls you can also use smokeless powder.

Also 1% red iron oxide will color it for fun.

[Bert]

In regards to the first type of ignitors shown in this thread, how does the Zirconium content effect the impact and friction sensitivity of the pyrogen?

I have heard of commercial ignitors igniting when being stepped on or otherwise mis-handled, and was wondering how these stand up. Also, if i was to replace the Zirconium with lighter flints, as NBK suggests, would this make them more or less sensitive?

Zirconium or other transition metals such as Titanium increase friction and impact sensitivity of pyrotechnic mixes. When used for paintball type spark hits in movie work, fine Zr powder is merely loaded into a paintball capsule with some grit (similar to aquarium gravel) and fired at a hard surface. The impact alone causes the Zr to ignite and air burn in a shower of sparks.

While pyrogens for fast acting low wattage ematch use are intrinsically sensitive, adding such metals likely makes them more so. I have seen the effect of shooting a staple through an ematch head when a pyro foolishly thought to hold down a finale chain by stapling it to a mortar rack- And I regularly demonstrate ematch sensitivity to new crew members by tapping one with a hammer on a hard surface, and striking another one on a match book's scratch pad. Both of these methods reliably light or explode the ematch, and the demo helps me convince the new people not to make insertion easier by removing the shrouds our matches come with.

Obviously, the ferrocerium http://en.wikipedia.org/wiki/Ferrocerium compositions of modern lighter flints are designed specifically to spark under impact and friction. They are probably going to have a similar effect on a mix, but you're going to have to do the comparative friction shoe and drop testing yourself if you want a specific answer I'd guess. Why not do some testing and get back to us?

By the way, how are you planning on comminuating lighter flints? I believe any force that would fracture or grind them would tend to ignite them.

[nbk2000]

I've ground lighter flints using the striker wheel in the lighter.

Just turn it really slow and hold the lighter at least six inches over the collection surface. It takes forever to get a miniscule amount, but it's doable.

It might be possible to do it much faster if you did it in (for instance) a five gallon bucket that had been filled with desiccated CO2 from warmed dry ice, to prevent ignition, similar to the spark prevention test I did with a grinder in a CO2 atmosphere in my Active Coolng for Power Tools (http://www.roguesci.org/theforum/showthread.php?t=4832) thread.

[Dibs]

I found the site that I seen a while ago.

http://www.rctparadox.net/spatulatzar/igniters/

Very clear pictures and instructions...

[dumbrella]

I was considering grinding the lighter flint under water, to lower the chance of ignition, and using wet-or-dry sandpaper. Would you still have to grind it slowly, or does the immediate presence of water keep it a fairly safe practice?

[nbk2000]

Doing it dry under an inert gas atmosphere would be better, to prevent any interaction with the water (like rusting).

[Altroman]

The mischmetal which flints are composed of is a mixture of pyrophoric metals rich in cerium, very similar to zirconium. The problem with using water is that you may get some oxidation. I've used light kerosine, which lubricates, cools, and is a reducing agent. Just one drop is enough. Then scrape off the mass of shavings, spread them out, and let dry for a day or two. This way you get a fraction of a gram of very energetic powder with very little oxidation. The flash point of kerosine is high enough not to be an issue, even if the sparks do fly by mistake.

[hst45]

I use the bridgeless igniters from Brainfever's site. I find that they work best if the graphite is very, very fine, and the NC lacquer is very thin. Coarse graphite and/or thick lacquer will work, but with a noticeable and annoying delay. I apply two layers, and then topcoat with one more layer of lacquer. They fire immediately from a 14.4volt battery.