Simple igniter for thermite

[Nessalco]

Some years ago I developed a simple igniter that will easily light ferric thermite. It also works well for hard-to-light forms of APCP (which is what I developed it for in the first place).

 

Strip 1/4" of insulation from a piece of #24g shooters wire, but do not separate the wires. Dip in a 50/50 mix of -325 graphite and cupric oxide bound with 5% NC lacquer, and let dry.

 

These require a high current source, so will not work with CD systems. When hit with high current, the igniter forms little balls of molten copper, and will continue to make slag as long as current is applied, up to ~5 seconds. There is little to no gaseous byproduct.

 

Kevin

[norb]

Nice done!

[NeuroticNurse]

That is an awesome method of ignition, I will try to make it at some point... Mine to ignite it at present is to use a plain ordinary sparkler...

[taiwanluthiers]

What temperature is needed to light thermite? Will a propane torch do it or does it need to be hotter than that? Are molten copper enough to light it?

[Nessalco]

Based on personal experience, I wouldn't recommend lighting thermite with a torch. It tends to heat in a mass, then 'go' all at once.

 

Kevin

[LambentPyro]

I've done lots of thermite on the past.

 

One thing I've learned is you NEVER want to be close to the mixture when it lights.

 

I use Mg ribbon, as it doesn't produce sparks, but unfortunately, it does produce some very high temp MgO flake that can potentially ignite the mixture prematurely.

 

Oh yeah, don't do MnO2 and Al (-425 Atom) 2:1 thermite. It produces an enormous shower of Al sparks that easily ignites any dry tinder in the area. I learned the hard way with that one.

 

Stay safe.

Edited November 5, 2013 by LambentPyrotechnics

[taiwanluthiers]

Just wondering, is there any kind of prime that can be stuck to the end of a visco fuse to actually ignite thermite, or will any metal fueled comp do it? The way I lit it was using a very slow flash mix (50:50 mix of 325 mesh spherical Al and pot. Perchlorate, burns bright and slow)

[mabuse00]

I always had enormous troubles with my thermite. I think the iron oxide is somehow not clean, I'm not sure...

 

Solution 1:

Make a little batch with dark pyro aluminium. This will light from a fuse and on the other hand will light your main batch.

 

Solution 2:

I took a 12mm pumped star made of NaNO₃ and MgAl 50/50 and "glued" the fuse onto that with a big blob of Pinball Prime/NC Slurry. Burns slow but very hot and will ignite anything...

Must be about the same like the perchlorate mix you posted. I would also try to pump it, it's more convenient to use that way.

 

If you often work with thermite you can make such devices in advance and stock some.

Edited November 6, 2013 by mabuse00

[Seymour]

In my experience, any MgAl fueled colour star mix lights thermite.

[gasbag]

I've got a question regarding fues. In particular, underwater fuses....

I've seen numerous instructions and video clips of how to make fuses that burn underwater. But if you're looking to make a thicker fuse (e.g.) that would be capable of igniting sparklers and/or thermite.

E.g. Slow, hot burning mixture (perhaps Aluminium + Sulfur?) at the bottom of a Zip-Loc storage bag, rolled up tightly, then either tightly wrapped in alfoil, or sprayed with a rubberised spray. e.g. http://www.getflexseal.com/

I'm worried that such a fuse might burn much quicker due to the fact that it's sealed.

Has anyone had any experience here?

[Seymour]

Why not just use a fuse that is cheap and widely available that burns under water (like decent quality Visco) anmd then prime the thermite with a hot mix, for example, a primed coloured star as per my typical thermite lighting method.

 

However if you are determined to have a fuse that can light any kind of mixture, including hard to light thermite (in reality some thermite is very easy to light, black match being sufficient if you use fine enough ingredients), then I suggest that you use a hot burning mix in a tube like a Spolette.

 

I have used the method where you wrap a mixture in Al foil in the past and do not trust it. It just does not produce a consistent enough fuse.Unfortunately the time I had it burn fast and skip most of the length and ignite the composition prematurely it was indeed with a type of thermite, CuO/Al. Having had my hand engulfed in the many thousand degree fireball produced, and obviously burned, I do not wish this on anyone.

 

Properly compacted in a tube there is much less risk of this occurring.

 

As for composition... I just find it really hard to see why not to simply use a coloured star mix, or a coloured star prime, unless of course you lack the chemicals to do so. In which case, I have had success igniting thermite with 60% KNO3, 20% Atomised Al (200 mesh), 15% Sulfur and 5% dextrin, usually in the form of a pumped star embedded in the thermite. Glitter mixes are very effective at lighting this pellet.

 

May I ask why it is that you are wishing to light thermite and sparklers under water? While strange things are sort of the norm around here, that is a strange desire indeed.

[gasbag]

Why not just use a fuse that is cheap and widely available that burns under water (like decent quality Visco) anmd then prime the thermite with a hot mix, for example, a primed coloured star as per my typical thermite lighting method.

 

However if you are determined to have a fuse that can light any kind of mixture, including hard to light thermite (in reality some thermite is very easy to light, black match being sufficient if you use fine enough ingredients), then I suggest that you use a hot burning mix in a tube like a Spolette.

 

I have used the method where you wrap a mixture in Al foil in the past and do not trust it. It just does not produce a consistent enough fuse.Unfortunately the time I had it burn fast and skip most of the length and ignite the composition prematurely it was indeed with a type of thermite, CuO/Al. Having had my hand engulfed in the many thousand degree fireball produced, and obviously burned, I do not wish this on anyone.

 

Properly compacted in a tube there is much less risk of this occurring.

 

As for composition... I just find it really hard to see why not to simply use a coloured star mix, or a coloured star prime, unless of course you lack the chemicals to do so. In which case, I have had success igniting thermite with 60% KNO3, 20% Atomised Al (200 mesh), 15% Sulfur and 5% dextrin, usually in the form of a pumped star embedded in the thermite. Glitter mixes are very effective at lighting this pellet.

 

May I ask why it is that you are wishing to light thermite and sparklers under water? While strange things are sort of the norm around here, that is a strange desire indeed.

Thanks very much for your reply. My apologies if my query seems somewhat clumsy....but I'm a Newbie to this Forum.

 

Unfortunately, where I live, Visco Fuse isn't readily available, hence my inquiry. Also, can you please explain what "Spolette" is?

 

I've made a few other inquiries in the Forums as well. My queries are more related to physical structure, more so than the actual chemistry side of things.

 

Again, thanks.

[gasbag]

Why not just use a fuse that is cheap and widely available that burns under water (like decent quality Visco) anmd then prime the thermite with a hot mix, for example, a primed coloured star as per my typical thermite lighting method.

 

However if you are determined to have a fuse that can light any kind of mixture, including hard to light thermite (in reality some thermite is very easy to light, black match being sufficient if you use fine enough ingredients), then I suggest that you use a hot burning mix in a tube like a Spolette.

 

I have used the method where you wrap a mixture in Al foil in the past and do not trust it. It just does not produce a consistent enough fuse.Unfortunately the time I had it burn fast and skip most of the length and ignite the composition prematurely it was indeed with a type of thermite, CuO/Al. Having had my hand engulfed in the many thousand degree fireball produced, and obviously burned, I do not wish this on anyone.

 

Properly compacted in a tube there is much less risk of this occurring.

 

As for composition... I just find it really hard to see why not to simply use a coloured star mix, or a coloured star prime, unless of course you lack the chemicals to do so. In which case, I have had success igniting thermite with 60% KNO3, 20% Atomised Al (200 mesh), 15% Sulfur and 5% dextrin, usually in the form of a pumped star embedded in the thermite. Glitter mixes are very effective at lighting this pellet.

 

May I ask why it is that you are wishing to light thermite and sparklers under water? While strange things are sort of the norm around here, that is a strange desire indeed.

The other issue is "robustness". Fuses that are lit, then the item carefully placed on the ground....that's as easy as opening a beer. But a fuse that can be lit, where the item is then thrown....where the fuse doesn't snap/break/distort/fizzle out....that's a different matter entirely. The point to keep in mind is that products such as Visco are simply not available where I live (Australia).

[Mumbles]

What kind of things are you intending to light in your hand and then throw? Sounds irresponsible to me.

[psyco_1322]

Also, can you please explain what "Spolette" is?

 

 

It basically comes down to a paper tube that is rammed with black powder, for use as a fuse. They are customary to cylinder shells, where time fuse is just not something you want to use.

[LambentPyro]

If you cannot obtain visco, just use the Mg ribbon, much easier to obtain, and it's much safer, especially in the wind.

[Sparx88]

Hello

 

I just registered and am happy to have found this place. I have been a pyro for 25 years and have within the last 3 years started really trying to make and shoot my own without using pre manufactured stuff. So I'm a long way off from being a grand master or anything like that. But never give up.

 

I hope this alternative for igniting thermite will work for you if you try it out.

 

first you need 3/32 or 1/8 visco. 6" peice

-BP meal 3 gms

-KClO₄ 2 gms

-Dark AP .5 gm

-Dextrin .5 gm

-water

-denat or rubbing alcohol 70%

 

mix them with a little warm water and stir until a smooth thin paste. Then add alcohol, just a little, until mixed through and can be shaped into a cube as it evaporates. With the cube still wet enough to push the fuse into the center of a side and out the other 1/4". Kinda re shape the cube so it's tight around the fuse and let dry on a screen for a couple days. etc etc

 

Bury the cube in the thermite to about a half inch over the top with the fuse pointing up and..... watch it burn.

 

Anyway thats all I got on that hope it helps.

Edited November 16, 2013 by Sparx88

[MWJ]

Taiwan.. From what I read Thermite ignites at around 3000 degrees F.