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Need help with mixture - primer for electronic match


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Posted (edited)

So, I have made up some e-matches with nichrome wire, and I'm working on finding a suitable, hot primer. I don't have my al powder here with me, so i'm trying to substitute fuels. I'm wanting to use strontium nitrate to make a hot, red flame with these igniters. As it stands, I'm using NC as a base inside a condiment cup, eyeballing a few grams of strontium, a couple grams of kclo4, a couple grams of sulfur, a sprinkle of iron oxide, and with that have tried different fuels...Sugar seems to work, but it doesn't dissolve worth a damn and thus the ignition is hard to start. I tried lactose, but that wasn't worth a damn either. Is there something I can sub that would be more effective? I have some coarse sponge titanium but that is going to require too much heat to ignite. What else could I use?

 

(I added the iron oxide before I realized I had no al powder)

 

Edit: Let me add - I was trying to find something that seemed like it would work, and I felt like the sugar would have worked. But alas, it did not. The ignition temp is just too high. Is there a way to lower it while using strontium in the primer? I really want the red flame (:

Edited by pycharm
Posted

IMO in a commercial igniter there are two comps. One is very small and very sensitive and takes fire from the really tiny amount of heat from the fusing wire. The other is a viscous mix containing enough NC as lacquer and other things to affect the flame style or colour.

 

From once reading a text on the prep of percussion caps there are some odd chems and perhaps some primary explosives in the sensitive mix, some of these cause corrosive effects on the metals present (inc perhaps eating the bridgewire).

  • Like 1
Posted

I could perhaps mix Armstrongs mix with a bit of NC as my primary and then use my strontium mix for the second coat. Just trying to use what I have without having to buy anymore al

Posted
Mixing in very minuscule proportions. Just testing different formulae 🙃
Posted
Not to be a jerk, but maybe start by measuring rather than eyeballing?
  • 4 weeks later...
Posted

Armstrongs mix is a good way to get things to go off early or unexpectedly. Shimizu's formula of 75% potassium chlorate + 25% charcoal, airfloat. Then coat with NC. Very small amounts only. This is a sensitive mixture to both heat and friction.

  • 1 year later...
Posted

I could perhaps mix Armstrongs mix with a bit of NC as my primary and then use my strontium mix for the second coat. Just trying to use what I have without having to buy anymore al

 

I have done this with very small amounts of Armstrongs Mixture.

 

Initially just Armstrongs in NCL makes for a definitely loud snap.

 

I am now covering the (Armstrongs + NCL) with (BP meal + NCL) to see if I can get a more reliable flash, rather than bang.

I am hoping that the KNO3 & S in the meal will give that.

 

Armstrongs must definitely be treated with the utmost respect and caution.

Not for the faint of heart.

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