Sciencemadness Discussion Board

Tracer Igniter

NedsHead - 26-7-2022 at 08:24

Hi,

I've started this thread to bring exposure to the issue I'm having with igniting homemade tracers over in this thread https://www.sciencemadness.org/whisper/viewthread.php?tid=72... and hopefully get some new ideas to test in the field.

I'm a bit limited by what chems I have access to these days and the igniter formulas I have found online call for barium peroxide, which I don't have access to, but I do have some 50% H2O2, CaCl2 and ammonia, so I settled on making calcium peroxide for the igniter.

Although impure, when mixed with #200 magnesium and exposed to an open flame unconfined it reacts well and has a blinding, sharp flash of heat and light, but pressed to chamber pressures +10% (53,000psi) and down to -20% I haven't had an ignition.

I suspect one issue is the hard, glazed surface of the igniter isn't able to propagate a flame into the igniter mix.

My understanding is that near chamber pressures need to be met otherwise the pyrotechnic mix won't hold together during firing conditions, maybe I need a detonation train of igniter leading to the main pyrotechnic, I'm not sure.

I was thinking of trying lead nitrato-hypophosphite for priming the igniter, only because I have some, but I don't know if that's a good idea.

I'll load up a new batch of test rounds this weekend, so any ideas would be great. Non-corrosive preferred.

I'm really close to success, I just need to get this last piece of the puzzle in place.

Tracer formula being used (parts by weight)

- Barium Nitrate 60
- Hexachloroethane 20
- Shellac 10
- #200 Magnesium 30

Igniter

Calcium Peroxide 72g
#200 Magnesium 24g
Shellac Binder 1-2%



OneEyedPyro - 27-7-2022 at 04:37

Some percentage of red phosphorus added to your tracer compound for the igniter stage might work if everything is compatible and unlikely to detonate, even a thin layer of RP painted over the main tracer component would probably help.

NedsHead - 27-7-2022 at 06:44

Red phosphorus is also on the naughty list here, I've got a better chance of finding commercial made tracers:(

B(a)P - 27-7-2022 at 13:17

A little off topic, but you can purchase phosphorus from places like Onyxmet, but you would obviously need to check and satisfy yourself of the legality of importing presumably gram quantities.
I have looked on numerous databases of restricted substances and I have never got to the bottom of how phosphorus is restricted in Australia. I do know that if you want to purchase it locally (in Australia) you need to fill out an end user declaration.

violet sin - 27-7-2022 at 18:59

What about a physical process, like the final press with a conical die producing some form of mountain, spike or ridge of smaller cross section standing off from the projectile end towards smokeless powder? It would likely press the lower portion more tight than the tip of the cone, if it was only used on the final press. Give a gradient.

Perhaps a copper or silver wire/hair embedded in the primer bit, to capture the brief flash of heat towards primer comp.

Painted with a typical explosive primer like used in percussion cap for black powder(A)? Many look like a green paint in a copper cup from my experience. Or (B) Just set a black powder primer cap over the flair chanel with lacquer? It's thin metal with a large area and sensitive innards, if standing tall, it would likely go off. On firing the cartridge, would it not collapse into it's hollow space?

See if I can scrawl out a couple of images soon to append here. For now ya just get word pictures, lol. Ok it's been a long day in the warehouse here in northern Cali, she's a real warm 106°F so my logic may be a touch soft. We shall see

NedsHead - 27-7-2022 at 20:19

Quote: Originally posted by violet sin  
What about a physical process, like the final press with a conical die producing some form of mountain, spike or ridge of smaller cross section standing off from the projectile end towards smokeless powder? It would likely press the lower portion more tight than the tip of the cone, if it was only used on the final press. Give a gradient.

Perhaps a copper or silver wire/hair embedded in the primer bit, to capture the brief flash of heat towards primer comp.

Painted with a typical explosive primer like used in percussion cap for black powder(A)? Many look like a green paint in a copper cup from my experience. Or (B) Just set a black powder primer cap over the flair chanel with lacquer? It's thin metal with a large area and sensitive innards, if standing tall, it would likely go off. On firing the cartridge, would it not collapse into it's hollow space?


Good ideas Sinner,

I'll start by gluing a few granules of BP to the top of the igniter formula with NC lacquer, it's good enough to ignite firework stars, so you would think it also work for tracers, I actually thought BP on it's own would be enough but all compositions I've seen use magnesium and a metal peroxide.

Conical die will be next, I can turn one up on the lathe this weekend if the BP fails.

Off to work now, I'll come back to this thread later

NedsHead - 29-7-2022 at 08:13

Okay,

I've made a batch of NC lacquer so I can try gluing some BP granules to the top layer of igniter, and while I'm at it I'll make a new batch of igniter but this time I'll add 25% BP direct to the mix.

I'll also reduce my pressing pressures and instead of starting high and working back. I'll start low and work my way up.

Tomorrow I'll make a new pressing die that forms a conical point in the igniter, the smaller cross section can only help and I'll NC glue the BP granules at the tip, If required.

As soon as I have success I'll upload a video

[Edited on 29-7-2022 by NedsHead]

[Edited on 29-7-2022 by NedsHead]

OneEyedPyro - 30-7-2022 at 04:49

Quote: Originally posted by NedsHead  
Okay,

I've made a batch of NC lacquer so I can try gluing some BP granules to the top layer of igniter, and while I'm at it I'll make a new batch of igniter but this time I'll add 25% BP direct to the mix.

I'll also reduce my pressing pressures and instead of starting high and working back. I'll start low and work my way up.

Tomorrow I'll make a new pressing die that forms a conical point in the igniter, the smaller cross section can only help and I'll NC glue the BP granules at the tip, If required.


How can you be sure that your tracer composition doesn't burn too violently under high pressures?
Some things have an unusually highincrease in burn rate as pressure rises, pistol powders like Titegroup and Blue Dot are somewhat notorious for this.
6 grains might be within SAAMI spec and 7.5 might be a person going to the hospital or worse.
A simple positive feedback loop similar to a thermal runaway in a chemical reaction.

I'd use a string and some shielding, get a good test sample and obviously check the brass for any signs of excessive pressure. Maybe use a cheap gun too just in case :P

Fulmen - 30-7-2022 at 10:25

The tracer comp could in theory add to the propellant charge if consumed during firing. But as it is slow burning and not formulated for gas production the impact should be negligible in most instances.

OneEyedPyro - 30-7-2022 at 15:13

Quote: Originally posted by Fulmen  
The tracer comp could in theory add to the propellant charge if consumed during firing. But as it is slow burning and not formulated for gas production the impact should be negligible in most instances.


Better to know than assume when it comes to losing fingers and eyeballs.

NedsHead - 31-7-2022 at 07:37

I’m back from another night of testing, unfortunately no green streaks in the sky tonight,
But it wasn’t all negative, the igniter composition successfully ignited in 2 of the rounds pressed @ 32,000psi, but failed to transition to the tracer mix.



D2FF9692-3C9B-4EC3-8F59-F7D7836F6991.jpeg - 2.8MB

OneEyedPyro - 31-7-2022 at 07:49

Quote: Originally posted by NedsHead  
I’m back from another night of testing, unfortunately no green streaks in the sky tonight,
But it wasn’t all negative, the igniter composition successfully ignited in 2 of the rounds pressed @ 32,000psi, but failed to transition to the tracer mix.





Maybe work out a three stage train where you use a thin layer of a hotter burning middle stage?

Considering you had success with getting a couple to ignite at all it's likely the rest were close. Just a little something to bump up sensitivity, but what?.

NedsHead - 2-8-2022 at 01:44

Quote: Originally posted by OneEyedPyro  
[/rquote]

Maybe work out a three stage train where you use a thin layer of a hotter burning middle stage?

Considering you had success with getting a couple to ignite at all it's likely the rest were close. Just a little something to bump up sensitivity, but what?.


The formulas I’ve seen floating around online call for #325 mesh magnesium and the closest I have is #200, I did have some #325 aluminium but it’s so old it has oxidised and is no longer reactive.

I wasn’t able to find any #325 magnesium so I ordered another lot of aluminium, I’ll try a 50/50 magnesium/aluminium igniter and the same with a middle stage, perhaps 75/25 mag/aluminium.

Eventually I’ll find the sweet spot with the right pressure and igniter mix, I just have to keep trying

Herr Haber - 7-8-2022 at 19:58

If you need a primer for something that is hard to ignite you could use Si + KCLO4 or B + KNO3.
I dont think I saw many tracer compositions with HC but I assume that you should move away from it if you are trying to avoid corrosive gases.

Microtek - 23-8-2022 at 00:46

If the litterature calls for BaO2 for the igniter mix, you could make that from Ba(NO3)2 and H2O2:

http://www.sciencemadness.org/talk/viewthread.php?tid=13965