Reliable ignition of confined thermite

[FarmerFran]

I’ve been trying to find a reliable way to use visco safety fuse to ignite thermite confined in a cardboard or plastic tube. Obviously this would involve some sort of ‘step up’ process, probably a first fire composition of some sort. Here are the problems I’ve encountered so far:

Magnesium strips are unreliable. They don’t take fire easily and don’t ignite thermite reliably.

The standard first fire mix (5:3:2 KNO3:Al:S flash powder mixed 1:1 with thermite) usually explodes when confined and destroys the container, scattering the thermite. My guess is that the reaction produces too much gas.

I tried using a KClO4 and Al mix because there no gaseous byproducts. I tweaked the ratio to the point where it burned nice and slow (to avoid destroying the container). At this point, it only ignited the thermite about 50% of the time.

Adding an oxidizer to the thermite mix decreases the efficiency of the thermite reaction because it oxidizes the aluminum before the iron oxide.


All that said, I guess what I need is composition that will take fire from visco fuse and ignite thermite reliably but will not explode when confined in a sealed tube. The most important factor is reliability.

Any ideas would be appreciated, thanks.

[ultma]

a small amount of coarse grade Al:KMnO4:S flash intermixed with some of the thermite in the fuse area might work

[stupid939]

I have recently used a variety of methods to reliably ignite thermite. The first mixture is from united nuclear's waterfall mix and is as follows:

4.6g KClO4
1.4g Bright aluminum (or use a regular flash aluminum)
3.2g atomized aluminum (I use 200 mesh)

I mix these together and stir them into a nitrocellulose laquer (ping-pong/acetone) until if forms a syrup consistency. Then you just dip a length of visco fuse in it, let it dry, and its ready to go. I haven't had one fail yet, they cost about the price of the visco, and you only have to coat a small portion of the end (about 1/4" sphere).

You can also use sparkler powder, or make your own using a formula from the PFP database. Most pyro compositions that have aluminum in them will work, but I know for a fact that the above work.

[TreverSlyFox]

Hmmmmmm, would the "guts" from a road flare burn hot enough? Maybe make a "Hollow" in the top of the thermite or make a "core" and pack it with the road flare material. I'm sure it would burn long enough just not sure it would be hot enough.

[Bert]

Try a compressed pellet of red Lead oxide and Silicon (red thermite). It's more or less gassless, and should be plenty hot. Depending on the size of the Aluminum used, black Copper oxide/Aluminum might also serve. Why are you trying to light thermite in an enclosed tube- What is your application?

[newcastle]

Let me start by humbly admitting I have no knowledge of this and do not constier myself well versed in the subject by any means.

From what I could gather by watching some k3w1 videos on thermite it looks like sparklers were an ignition source. am I wrong would this work?

http://video.google.com/videoplay?docid=-4920811734286820266&q=thermite+sparkler

I hope I have not over stepped my bounds. I enjoy this forum thanks for having me.

[SafetyLast]

I have used powdered sparkler composition with great success, you might want to use a little BP above it to ensure a reliable ignition from the fuse.

[hatal]

I used sparklers to ignite thermite. The sparklers are lit up by a thin tungsten wire wrapped around the end of the sparkler.Ofcourse the thin wire has to be wrapped around it tight (small difficulty sometimes) and there is a 1-5 seconds delay between the electric charge and the actual ignition. I wouldn't call this the most reliable way but it worked quite a few times and its cheap in every store near you. The delay has to be tested a couple of times to get right timing...

[cracker]

If It's worth doing it's worth doing right,
http://www.pyrotechniques.org/dwilliams/thermalite/thermalite.html

I would also take another close look at Bert's suggestion, if it was me

[Cobalt.45]

I've had good results from Bullseye mixed with acetone to make a thick, sticky mixture.

To this, add either dark flake Al or magnalium at a 2:1 ratio, w/w. Before it dries, form it into flattened balls and insert your desired length of visco into it.

When dried, this will damn near ignite a cement block!

The advantages are that the ignitors are reliable, store well, not sensitive to shock, moisture, static, or friction. Nor will they react badly if in contact with most all metals, chlorates, nitrates, ammonium, barium, copper, strontium or other metallic salts.

Main disadvantage is that you will need to go buy a pound of Bullseye. Cost is ~$20.00/lb. at most gun shops.

Much the same thing can be done by substituting ping pong balls for the Bullseye. Six balls dissolved in acetone will give you enough "lacquer" to make ~2-3 ignitors, cost is a couple bucks.

[knowledgehungry]

While your method sounds great for most scenarios, this scenario requires the ignition mix to produce little to no gas, DBSP produces a very large amount of gas.

[Cobalt.45]

Silver Acetylide (I'm led to believe) generates no gas when ignited. How to use it in the scenario you've presented, is anybodies guess.

[mil&co]

SA is a stupid idea, we want the thermite to ignite, not to be blown away.

If Mg ribbon doesn't do the trick, try milling the components before mixing.

A sparkler will work (no need for powdering them, just stick them in the mixture), allways.
I've even seen thermite ignite from a spark which flew from a sparkler into the thermite, that was with 200 mesh Al and unknown (but by sight it seemed very fine) mesh iron-oxide.

[nbk2000]

SA is also absurdly sensitive and prone to spontaneous explosion when dry.

[deadman]

As someone else mentioned thermalite would be great. If I were personally wanting to do this, I would use a visco with a coating of Mg+NC lacquer at the end placed in the thermite.

What is the use of thermite in a tube? Are you just trying to make a thermite salute?

[Mr Science]

Instead of using Mg ribbon as what you said earlier, try magnesium shavings.

It has the same shape like paper mache on a pinata (sorry this is the best I could come up with for now), and light about 1/2 a handful of it on on of the thermite.

Perhaps for better ignition, 'bury' some of the Magnesium 1/2" underneath the thermite as well, covered by the rest, so it is certain some areas of the thermite will receive enough heat, and ignite. I have been making thermite since october, and shavings worked for me every time.

[c4goesbang]

Here is what I use to light thermite with Visco.

KClO4 (2 Parts) by weight
German Black Aluminum (1 part) by weight
Nitrocellulose Lacquer (4 drops per gram of mix)
Acetone (As needed)

I usually make a 4 gram batch. This is the same pyrogen, I use for my electric igniters.

Add 12 to 14 drops of NC Lacquer to 3 grams of KCl04 (fine powder, no lumps)
Add enough acetone, a few drops, and stir with a wooden stick, to form a thin slurry. I use a pop sickle stick available at kraft stores. Wetting the KCl04 first reduces the chance of accidental ignition.

When mixed well add 1 gram of aluminum powder. I use German Dark. Mix well, adding drops of acetone if needed to form a slurry. I use a small, 3” diameter ceramic bowl for mixing.

Dip ¼”to 1” of 1/8” Visco in the slurry. I usually let it dry, this stuff dries very fast, and dip it a second time. You can dip it more times if you want. Stir often and add acetone as need, to keep mixture from drying out.

When completely dry you can dip in NC Lacquer to waterproof but I usually don’t, for lighting thermite because it pops violently.

I use safety goggles, (just in case)

Safely discard any left over mixture. I usually burn leftovers (outdoors)with a piece of Visco. Light fuse and get away fast.

1/8” Visco, dipped in igniter mix.
http://i168.photobucket.com/albums/u166/mortarfire/Thermite009.jpg

Small plastic pill bottle with 25 grams of thermite. I use these for campfire starters.
http://i168.photobucket.com/albums/u166/mortarfire/Thermite013.jpg

(Video) 25 grams of thermite burning, confined in a small plastic bottle, using Visco and primer described above.
http://s168.photobucket.com/albums/u166/mortarfire/?action=view&current=Thermite017.flv

[Gumby]

If you used nanopowder Al and Fe you'd have no problem getting easy ignition of the thermite mixture from a spark plug, assuming the mixture was properly homogenized. However with that fine of powder your container is likely to explode under the pressure from the reaction unless something stronger were used (ie steel).

[Stormhelm]

Well, I found something interesting in Ellern, page 194, that deals with ignition of thermite. And I quote: "...a mixture
of magnesium and barium peroxide, formed into a small ball with
the help of some collodion and provided with a length of magnesium
ribbon for ignition, has been used in Germany under the name of
Zundkirsche (ignition cherry.)"

I guess visco could be used instead of magnesium ribbon. And wouldn't this be rather gasless, apart from the collodion?

[209]

Like Gumby said, a real simple way to ignite thermite is just to use real fine ingredients. I used ordinary Iron Oxide (homemade) powdered in a ball mill and 625 mesh aluminum powder.

This method is the best because it can easily ignited with a pocket jet lighter. If you don't have a scale the best is a 1:3 ratio (Al - iron oxide) If powdered as I explained, it will ignite easily. You must be careful though. 625 mesh aluminum is REAL fine. Any finer than that and risk an explosion instead of the mix burning. The 1:3 ratio and 625 mesh aluminum seems to be the sweet spot for igniting thermite.

For quite some time, I couldn't find fine aluminum. I had to grind it by hand with a file. I dont know where I found the patiences but I did. The thermite wasn't great, hard to ignite, but when it did ignite, I used an old frying pan as the base for it to burn in.


As soon as I used 625 mesh aluminum I noticed an immediate difference, it was not bright, it was BLINDING. And it burned much faster. I lit the new mix in the same pan as my old thermite and it melted a 4" inch hole through the middle!

Fine aluminum is well worth it!

[nbk2000]

Alum or aluminum?

These are two different chemicals, with two entirely different results, so don't use abbreviations that can be confused with another (non-abbreviated) chemicals name.

[209]

Right, I meant aluminum powder, alum is that stuff at the pharmacy, not sure what it is used for though.

[cracker]

If I were personally wanting to do this, I would use a visco with a coating of Mg+NC lacquer at the end placed in the thermite.

This would otherwise be a good idea but,
This will not work, there is no Air for the Magnesium to burn in, if confined, and yes I tried it to be sure.

[nbk2000]

Couldn't magnesium ribbon be electrolytically coated with an oxide layer, turning it into Thermite ribbon?

Then lack of air wouldn't be a problem as long it was heated hot enough to cause a Thermite reaction.

[Bluebanshee]

I assume youre not referring to coating the magnesium with a layer of magnesium oxide?

Couldn't magnesium ribbon be electrolytically coated with an oxide layer, turning it into Thermite ribbon?

Then lack of air wouldn't be a problem as long it was heated hot enough to cause a Thermite reaction.

theres obviously no energy to be gained from the reaction between magnesium metal and magnesium oxide. as the products of this would be magnesium oxide and magnesium metal.

I found that homemade black powder was quite sufficient to set off thermite, I have also used sparklers which were v effective and probably give out less gas.

[defiant]

I realize this is a shit thing to do, but I'm in the process of scanning a book:

http://www.google.com/search?hl=en&q=underwater+magnesium+fuse

[nbk2000]

Believe it or not, Bluebanshee, I actually know what I'm talking about.

The oxide layer would obviously NOT be magnesium oxide, but the oxide of another metal, such as iron or copper, as otherwise it wouldn't be a Thermite reaction, now would it? :p

Though it would burn very quickly, so squib-ignition would be required for safety.

[Bluebanshee]

Oops, sorry NBK, I didnt intend to insult your intelligence. it just looked a bit like that was what you meant.

[Alexires]

Although I don't know what you could use for NBK's thermite fuse idea, what about the old Palladium+Aluminium wire. It was on the old forum video site.

Problems is that I cant remember the link for it, or find it.

You remember that NBK?

Edit: I went and found the video in my collection of a Palladium clad aluminium wire. Burns hot and FAST. You might be able to initiate it with and electrical nichrome initiator that gets so hot the nichrome melts. See US patent 5392713 regarding the fuze. Also an interesting patent.

[evilgecko]

Powdered aluminium reacts with sulphur and is a good mixture to start thermite with.

I think the reaction goes:
2Al + 3S = Al2S3

I think I used to mix by weight 2 parts Al to 1 part S. It ignites by flame or fuse and reliably sets of thermite.

[nbk2000]

Wrap the magnesium ribbon in Teflon tape. The burning Mg breaks down the Teflon (PTFE), and the liberated fluorine acts as an oxidizer, creating even more heat. :)

[drunkenpanda]

From the thermite reactions I have done the best results come from using KMnO4 and glycerin. This might cause too much gas but it isn't that explosive. Also as has already been mentioned sparklers will work great. I also would like to echo Bert's question: What are you using this for?

[Gumby]

You know there are other thermite reactions that have a lower activation energy...

[Cindor]

To start Fe2O3/Al Thermite I use:

First FP, then 8/2 FP/Th mixture, third a 5/5 FP/Th and finally a 2/8 FP/Th mixture. Aprox 200mg of FP, 300 mg of 8/2 FP/Th, 350 mg of 5/5 FP/Th and 500/600 mg of 2/8 FP/Th. One above the other.

The FP is the one that is in contact with the fuse, above the other ones, and 2/8 FP/Th is the one that is in contact with the Thermite.

All mixtures are by parts.

FP: Flash Powder (KClO4/Al)
Th: Thermite (Fe2O3/Al)

[stupid939]

Regarding using flash powder to ignite thermite - I have added 5% dextrin to the regular 70/30 flash powder and granulated it through a course strainer. I use this most of the time when igniting standard thermite, and it has not failed me yet. The simplest way to do this is to make a small dimple in the thermite and pour about 1g into the divot. Add a length of visco, and you're set. I have also wrapped granulated flash powder in a square of aluminum foil with visco coming out of the top. If you make these ahead of time, you don't have to take time to set up the thermite later.

[Xenodius]

You know, I recently made some Sr(NO3)2 metallic/organic fueled stars, comp as below:

IO/O Red:

KCLO4: 14%
Sr(NO3)2: 50%
Hexamine: 13%
Magnesium, coarse: 4%
Magnesium, powder: 6%
Aluminum, ~400m At. 4%
PVC/Parlon: 9%
(I bound with +6.5% dextrin, the amount of Mg present isn't enough to cause a reaction...)

My 1/2"x1/2" stars burn very well, they weigh 2.2 grams yet illuminate a 8' circle for 7+ seconds.

Anyway, my point is, if these things wont ignite thermite (They spray Mg sparks and burn incredibly hot) then a 1" or 1 1/2" comet certainly will. Just use one of those exploding comet bases so that you can stick a fuse in there, then wet with a little acetone to make it stick, and voila! Thermite ignition, instantly. A Mg/Al/Perc mix would probably do better though. My point: Instead of granulated or powdered ignition mixes, why not stick a star on the end of your fuse for prime? Pour thermite, insert star-primed fuse, light, enjoy!

PS: If you drilled out one end of your wood dowel/aluminum ram @ 1/8", then inserted a ample piece of visco in, only sticking out 1/4-1/2 inch, you could probably pump fused stars specifically for thermite.

[hst45]

I use 9 parts copper oxide to 2 parts blackhead aluminum. A small charge of this thermite reliably takes fire from visco and generates sufficient heat to ignite other thermites.

[QuickCheese]

I have recently used a variety of methods to reliably ignite thermite. The first mixture is from united nuclear's waterfall mix and is as follows:

4.6g KClO4
1.4g Bright aluminum (or use a regular flash aluminum)
3.2g atomized aluminum (I use 200 mesh)

I mix these together and stir them into a nitrocellulose laquer (ping-pong/acetone) until if forms a syrup consistency. Then you just dip a length of visco fuse in it, let it dry, and its ready to go. I haven't had one fail yet, they cost about the price of the visco, and you only have to coat a small portion of the end (about 1/4" sphere).

You can also use sparkler powder, or make your own using a formula from the PFP database. Most pyro compositions that have aluminum in them will work, but I know for a fact that the above work.


My 'friend' has been having a real problem with getting his thermite to ignite. I don't know if it's how he's combining the thermite (about 25% Al with 75% Fe3O4). I know that there are much more complicated ways to make thermite, but he figured to start off with something simple. To ignite it, he tried using magnesium ribbons, but they weren't reliable. I'll suggest what you tried and if it works reliably, I'll see if we can't get a video of it and post it.

[hst45]

What size and shape Aluminum is your "friend" using? If you're, uh, "he's", using relatively large size spherical, for example, it will take a greater amount of energy to ignite. Try some German Blackhead if "he" has any, and it should ignite more readily.