Sciencemadness Discussion Board - Exotic thermites & analogs

Exotic thermites & analogs

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Fenir - 24-10-2013 at 16:29

By adding a drop of water to a potassium permangenate and glycerin slurry, one can speed up the reaction time immensely. This is quite helpful when igniting thermite mixes.

elementcollector1 - 24-10-2013 at 16:32

Quote: Originally posted by A Fresh Lunatic

SO, how can we determine if Mercuric Oxide would have a thermic reaction with copper metal , other than trying it? presum,ably, the end products woudl be mercury metal and cupric oxide ?

How about looking up the reactivity series?

DraconicAcid - 24-10-2013 at 16:45

Quote: Originally posted by elementcollector1

Quote: Originally posted by A Fresh Lunatic

SO, how can we determine if Mercuric Oxide would have a thermic reaction with copper metal , other than trying it? presum,ably, the end products woudl be mercury metal and cupric oxide ?

How about looking up the reactivity series?

Better yet, calculate the enthalpy of reaction. If you're lazy, you can get WolframAlpha to do it for you.

Metacelsus - 24-10-2013 at 17:49

Quote: Originally posted by DraconicAcid

Better yet, calculate the enthalpy of reaction. If you're lazy, you can get WolframAlpha to do it for you.

Even better yet, calculate the enthalpy and entropy. That way, you can determine what the temperature needs to be for the reaction to be spontaneous.

A word of caution: If the reaction is spontaneous and exothermic, it may produce highly toxic mercury vapor.

[Edited on 25-10-2013 by Cheddite Cheese]

Yttrium Thermite

siegfried - 1-2-2014 at 15:36

After a semi-failure with zinc thermite (the entire pile of thermite did not burn), I tried using 5 grams of Y2O3 and 2 grams of powdered Al. The mixture was placed on a piece of tile flooring outside with an air temp of 40 degrees F.

The results were very gratifying. The mixture burned much quicker than conventional iron thermite. The temperature was high because the slab of tile cracked and all that was left were chunks of fused Yttrium metal and Al2O3.
I have no way of measuring the actual temperature of the reaction but the melting point of Y2O3 is 2,410C, Yttrium metal melts at 1,522 and boils at 3,338.

The 99.99% pure Y2O3 was purchased on Ebay and, for a "rare earth" metal oxide, was relatively cheap.

Zyklon-A - 7-2-2014 at 10:26

Here, halogen wondered if 3NaCl + Al --> AlCl₃ + 3Na would work because it works with NaOH and Al.
Why wouldn't it work? The enthalpy of formation of AlCl₃ is −704 kJ·mol, while NaCl's is only −411.12 kJ mol.
Is it because there is more atoms in AlCl₃ than in NaCl? And thus higher molar mass, so it releases more energy because it contains more matter?

[Edit] Sorry if this question is stupid, I just did a little research on the subject.

[Edited on 7-2-2014 by Zyklonb]

Metacelsus - 7-2-2014 at 11:52

Quote: Originally posted by Zyklonb

The enthalpy of formation of AlCl₃ is −704 kJ·mol, while NaCl's is only −411.12 kJ mol.

Yes, but it's 3 moles of NaCl, so net enthalpy change is +529.36 kJ/mol.

Zyklon-A - 7-2-2014 at 12:11

OK, that's kind of what I was thinking.

Bismuth - 22-2-2014 at 22:38

Ag₂SO4 thermite

I gave this a whirl about three years ago. I used 300MESH magnalium powder as the fuel and diapered the mixture together. The mixture was ignited with a piece of visco-fuse.

vlcsnap-2010-11-11-19h12m36s190.png - 139kB

The composition would self-confine easily and it was a very vigorous reaction. Due to no presence of nitrogen in the reagents, one could only deduce that it would decompose the nitrogen in the air into various oxides, as evident from the orange fumes in this still image.

Compared to silver nitrate, silver sulfate has a low solubility in water with a quick glance at Wiki quoting its solubility at 0.79g/100mL at 20 degrees Celsius. I actually never experimented whether or not it would be water sensitive, but having no interest in its practical uses it wasn't an interest at the time.

I also experimented with silver oxide, but the results weren't nearly as exciting. Perhaps my ratio calculations were off. To this day, I still have 300g of both these silver salts, as well as acetate...

Zyklon-A - 28-3-2014 at 11:42

I just tried the CuO-Al thermite, it was much slower than I expected.
The walls of my crucible where coated in a red-orange copper color, but no nuggets of copper where recovered.
I am dissolving the mess in dil. HCl (aq) as I type. Large volumes of a flammable gas (hydrogen I assume) where given off.
My question is, why would H₂ evolve?
The reaction of the thermite would be: 3 CuO + 2 Al → 3 Cu + Al₂O₃.
None of the reactants react with HCl to produce H₂.
The purity of my CuO is unknown, I made it by dissolving a Cu anode in water with electricity. The resulting CuOH was heated to make CuO. My Al is quite pure. One possibility is unreacted Al, but my stoichiometry was correct, perhaps my scale is inaccurate?

Dornier 335A - 28-3-2014 at 13:43

CuO/Al thermite is rather unpredictable in my experience. I've made nano-CuO/MgAl which did not burn completely, although it exploded violently on heating. If you want higher burn speeds, some confinement or preheating is necessary as small amounts unconfined with different particle sizes will burn almost identical speeds.

Your "mess" probably contains quite a bit of aluminium. That would at least explain the evolution of hydrogen gas.

Zyklon-A - 28-3-2014 at 15:34

Ok, I might try it again, there was no practical reason for the experiment.
I did find a lot of tiny grains of Cu after the HCl treatment was complete, but some gray powder was also present.
I just through it out, because I didn't want to try to separate it.

Bismuth - 30-3-2014 at 18:27

Quote: Originally posted by Zyklonb

I just tried the CuO-Al thermite, it was much slower than I expected.

That is a very vague conclusion. I know for a fact that copper (II) oxide from a ceramic supplier and any fine aluminum powder (eg. 325 mesh) will deflagrate almost as fast as conventional 7:3 flash powder. It is dangerous stuff.

The reason it may have been a slow reaction for you could be the purity of your reactants (from your post), their particle size, how homogenous the mixture was prepared and/or the ratio.

Someone could read your one-off comment and interpret that it is safe to ignite a large quantity with a gas-torch because it will burn slow, when in actuality it would practically explode.

Specifics matter! You never know who may read your findings and reproduce the experiment with the same expectations.

Zyklon-A - 30-3-2014 at 19:02

Like I said, I assumed that it would be faster, if someone tries this, thinking it would be slow, just because of my account, without reading anything else, it would be his/her fault.
Al was ~350 mesh, I'm pretty sure the copper II oxide was impure, it was mixed very well.
I shall make some more, and try again.
BTW, can you light Al/CuO thermite with a torch?
I do have Mg ribbons, but instead of waiting them, I light all my thermites with a visco fuse coated in KClO₃, it's never failed, but I haven't really tried any hard to light thermites yet.
[EDIT] Typo.

[Edited on 31-3-2014 by Zyklonb]

Zyklon-A - 10-4-2014 at 13:41

Are you asking a question?

jock88 - 1-6-2014 at 11:44

http://www.popularmechanics.com/technology/military/research...

Copper Oxide + Al or Mg cutting torch.

Amos - 5-10-2014 at 21:17

Quote: Originally posted by j_sum1

Forgive me if this has been covered. I'm new here and have only read about 20% of this thread.

I had questions about the Al-S method for ignition of thermites.
My standard method is KMnO4/glycerine with a strip or two of Mg ribbon. Several people here are extolling the virtues of Al S.

I mixed up some 400 mesh Al powder and garden quality sulfur in a 1:2 ratio and hit it with a butane burner. I got the two to react under the flame but it was not self-sustaining. I also got a brownish gas coming off which I was not expecting.

So, my questions
1. What am I missing here?
2. What set up are others using to get this to act as an igniter?
3. What the cow was the brown gas? It looked like N2O but that seems really unlikely. Do I have sulfur that is that full of impurities?

This stuff usually burns quite well and pretty quickly as well for me. My first issue is your sulfur being "garden variety", though, which often contains 10%, sometimes more, of bentonite clay. I don't know that this would matter a ton though. It could also be that your aluminum is too oxidized on the surface, this happens with older samples. Your brownish gas might've just been some dust kicked up by the reaction; sulfur dioxide fumes also look kind of misty and dirty to me also.

If you have the materials available, I often use a mixture of 2:1 potassium chlorate to powdered bituminous coal(most coal you encounter is this) as a thermite lighter; it's very reliable, and burns with a nice consistent rate, plus no sulfur dioxide/hydrogen sulfide smell. I've also been able to light thermite with coarse black powder. With both of these, you can just stick a visco fuse into the mixture, light it with time to spare, and walk away.

Amos - 5-10-2014 at 21:30

Oh, and for anyone wondering about the explosive properties of bismuth trioxide thermite, look no further: https://www.youtube.com/watch?v=lg8NLzUngr8

I believe this is SM user Tdep's channel; the video shows some pretty good examples of the explosive nature of this thermite.

blogfast25 - 14-10-2014 at 06:35

Quote: Originally posted by siegfried

After a semi-failure with zinc thermite (the entire pile of thermite did not burn), I tried using 5 grams of Y2O3 and 2 grams of powdered Al. The mixture was placed on a piece of tile flooring outside with an air temp of 40 degrees F.

The results were very gratifying. The mixture burned much quicker than conventional iron thermite. The temperature was high because the slab of tile cracked and all that was left were chunks of fused Yttrium metal and Al2O3.
I have no way of measuring the actual temperature of the reaction but the melting point of Y2O3 is 2,410C, Yttrium metal melts at 1,522 and boils at 3,338.

The 99.99% pure Y2O3 was purchased on Ebay and, for a "rare earth" metal oxide, was relatively cheap.

You're lying.

The RE oxides cannot be reduced with Al, their heat of formation is too high.

Y is not strictly speaking a lanthanide but Wolfram Alpha gives a value for Standard Heat of Formation of Y2O3 of - 1905 kJ/mol. Al2O3 is only - 1676 kJ/mol, so that reaction simply CANNOT proceed!

Trust me, if aluminothermy could yield RE metals, we'd all be doing it!

[Edited on 14-10-2014 by blogfast25]

Loptr - 14-10-2014 at 06:38

Quote: Originally posted by blogfast25

Quote: Originally posted by siegfried

The 99.99% pure Y2O3 was purchased on Ebay and, for a "rare earth" metal oxide, was relatively cheap.

Is it possible it wasn't Y2O3? Just kind of quick to call someone a liar.

[Edited on 14-10-2014 by Loptr]

DraconicAcid - 14-10-2014 at 07:59

I recently found a way to do the thermite demonstration in class, without the tedious mixing of powders and setting up of a tray of sand and other safety measures. Take two large rusty ball bearings, wrap one in aluminum foil, and smack them together. I just need to find a manganese ball bearing....

Metacelsus - 14-10-2014 at 08:27

I'm surprised that the impact is enough to start the reaction. Thermite generally needs a lot of heat to start.

DraconicAcid - 14-10-2014 at 09:05

Quote: Originally posted by Cheddite Cheese

I'm surprised that the impact is enough to start the reaction. Thermite generally needs a lot of heat to start.

The kinetic energy from the moving spheres* gets converted to thermal energy at a very small point. The physics instructor here does a similar demo with stainless steel ball bearings and a piece of paper (which gets a hole burned through it). I gave up regular thermite demos because of the safety issues and the hassle of igniting the stuff, but this works like a charm.

I tried folding some MnO₂ inside some aluminum foil, and smacking that between the spheres, but I don't know if it was reacting with the rust or the MnO₂. I may have to try again with the stainless steel ones.

*Yes, I've heard enough comments about "playing with my balls" that I will refer to them as spheres for the rest of my life.

blogfast25 - 14-10-2014 at 09:28

Quote: Originally posted by Loptr

Is it possible it wasn't Y2O3? Just kind of quick to call someone a liar.

Call it what you want. It's serious disinformation that could lead other members and Googlers to waste precious Y2O3 on something that can not possibly work, not even remotely.

Tar and feathers, please.

blogfast25 - 14-10-2014 at 13:23

Quote: Originally posted by No Tears Only Dreams Now

I believe this is SM user Tdep's channel; the video shows some pretty good examples of the explosive nature of this thermite.

And yet, what is proved by this kind of idiocy? You only need to do the thermochemistry calculation to know what will happen!

Of course with their kind of guesswork sooner or later someone will get hurt. It won't be so funny then...

Casting ingots with thermite

Jylliana92 - 24-10-2014 at 05:48

The well-known thermite reaction has as a product a molten metal(usually iron, but other metal oxides can be used too).
Until now, I've always caught the molten metal in sand or pebbles/rocks.

I was wondering if anyone of you has experience with casting an ingot this way, and mostly: what material can be used as a mold for the ingot, considering the temperature?

Because, I have a copper powder from a redox reaction, but a shiny copper ingot would be nicer, especially when made myself

PHILOU Zrealone - 24-10-2014 at 09:35

Hoi Jylliana92,

Maybe look first into the sticky tread about thermites ;-)
Misschien kijk eerst in de chat over vreemd/exotieke thermieten ;-)
Energetic materials- exotic thermites

CuO/Al thermite is quite energetic and sometimes even explosive if the grain/particle size is fine enough.

Doiiiggg/Schuss

[Edited on 24-10-2014 by PHILOU Zrealone]

Jylliana92 - 24-10-2014 at 12:20

Sorry about not looking well enough... thanks for merging them.

specialactivitieSK - 19-12-2014 at 02:10

I made titanium ingot, Aluminum reacting with TiO2.
I was curious about the reaction of Magnesium with TiO2, unpressed.
Out of 300 g of a mixture (TiO2 + Mg 62:38) I have received 160 g of black powder.
The flame burned up to 1 to 1,5 meters.
Is it possible to extract titanium, from this powder ?

[Edited on 19-12-2014 by specialactivitieSK]

[Edited on 19-12-2014 by specialactivitieSK]

Tdep - 19-12-2014 at 06:18

I believe that's a lower oxide of titanium. I would recommend re-doing the thermite with the black oxide to try and reduce it all the way to the metal

gdflp - 19-12-2014 at 06:46

Yep, that's most likely titanium(III) oxide.

DFliyerz - 6-1-2015 at 15:11

Could tantalum pentoxide from old tantalum capacitors be used to make tantalum-aluminum thermite, and produce tantalum metal?

Catching Molten Slag

nlegaux - 6-1-2015 at 19:28

Are significant amounts of product lost due to the molten slag flying off? If so, is there a good way to capture the pieces? I thought I may be able to take a ceramic water dish, drill a hole in the middle (for the fuse), and invert that over a flowerpot (this also may make it a bit safer...).

Explosive ZinCox / MagCox Thermite

andymadman - 8-1-2015 at 15:23

A little while ago I was experimenting with thermites that could be made with common and cheap metal/metal oxide combinations. I came up with two that rather than burn at a high temperature like a normal thermite, explode colorfully. The first combination I came up with is zinc and copper oxide (ZinCox I call it). I took cupric oxide (CuO) that I obtained by taking "Basic Copper Carbonate"
which I got from electrolysing copper pipes in tap water (I know, not very pure, but it has just enough ions to get the electrolysis started). Initially the source voltage was around 300V (From an inverter I made with 10 disposable camera flash circuits in parallel charging a 1200uF cap bank through rectifiers) then after enough copper ions had formed in the solution to allow the electrolysis to sustain itself I switched over to a 12V 15A power supply and let the electrolysis run for about 72 hours, replacing the anode occasionally and scraping as much of the basic copper carbonate into a separate container as I could manage. I later filtered the copper carbonated, air-dried it, and then heated it in a crucible at 600F until the green powder had turned uniformly black, and ground it using a mortar and pestle until it was a super-fine powder (it crushes like talc).

I mixed this in a 1 to 1 molar ratio with magnesium or zinc powder. When lit off in a fire-cracker-like package the materials explode rather powerfully. They both produce a small blue-white fireball and a lot of noxious smoke.

~~Cheers! Andymadman

[Edited on 8-1-2015 by andymadman]

careysub - 8-1-2015 at 16:41

Interesting.

Despite the lengthy list of compositions studied in this Sandia report, which considers some very exotic thermites (beryllium, hafnium and yttrium fueled):

http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=Get...

no compositions using zinc as a fuel are investigated.

chemrox - 8-1-2015 at 18:02

Could you post the Sandia report as a pdf? Thanks. Question; why does lemon and NaCl remove the CuOx from copper? Is it reducing the oxides or picking them up?

[Edited on 9-1-2015 by chemrox]

careysub - 8-1-2015 at 18:14

Quote: Originally posted by chemrox

Could you post the Sandia report as a pdf? Thanks. Question; why does lemon and NaCl remove the CuOx from copper? Is it reducing the oxides or picking them up?

[Edited on 9-1-2015 by chemrox]

It has been posted at least twice on various thermite threads, I hesitate to keep posting copies of it, it is a bit difficult to pull up the in-line posting on this forum though.

andymadman - 9-1-2015 at 16:32

Quote: Originally posted by chemrox

Could you post the Sandia report as a pdf? Thanks. Question; why does lemon and NaCl remove the CuOx from copper? Is it reducing the oxides or picking them up?

[Edited on 9-1-2015 by chemrox]

First off, the NaCl is not needed in the reaction, only the acid, I've tried it with both vinegar (acetic acid) and lemon juice (citric acid), the salt makes no discernible difference. If you look here: http://en.wikipedia.org/wiki/Basic_copper_carbonate you'll see that the material on a penny is likely not copper oxide as that does not form at low temperatures, it is not copprt hydroxide as that only forms in conjunction with copper carbonate, both of which are a noticible blue or green (you can look at my blog to see what color this is, l did an experiment where I electrolysed copper in sodium bicarbonate to create copper carbonate). My guess is the patina (copper tarnish) that forms is most likely a naturally stabilized insoluble mixture of copper sulfides and sulfates similar to the blue-gray sulfur-based tarnish that forms on silver which probably react with the acids to produce soluble copper acetate or copper citrate along with other compounds as a result of reactions with materials on the pennies.
Finally, if you look here:
http://nautarch.tamu.edu/CRL/conservationmanual/File12.htm
you'll see this:
"...copper sulfides only discolor the copper, imparting an unnatural appearance to the metal, and are easily removed with commercial cleaning solvents, formic acid, or citric acid."

I found this after I'd come up with my theory, but it does seem to support it.

Ragbips - 26-4-2015 at 08:13

Would thermite reactions with PtO2, PdO or Na2O work? I can't find anything about it.

blogfast25 - 26-4-2015 at 09:04

Thermiting PtO2 or PdO would be utterly pointless, which is why you won't find anything about it. Such thermites would in all likelihood fizzle because these oxides decompose at too low temperatures. Even if they worked it would be like taking a pneumatic drill to a crumbly nut: complete overkill.

Na2O is not a chemical that's easy to obtain or prepare. <b>NaOH</b> has been reacted with Al powder (there's some information on this forum, somewhere) but it's a fairly useless activity that results in mostly a mess.

If your only purpose is to generate heat from the oxidation of Al, consider reacting Al powder with KClO3: extremely exothermic. Even Al powder with CaSO4 (wall filler) runs at well over 2,500 C.

Kagutsuchi - 22-6-2015 at 02:12

I'm about to do some tests with PbO2/Al and PbO2/Mg in small amounts, including trying something to stabilise them from decomposion. I'll post my results here.

JJay - 30-11-2015 at 08:23

Quote: Originally posted by Polverone

Many oxides/salts of less reactive metals can react vigorously when mixed with an appropriate quantity of magnesium or aluminum and initiated by high temperatures (or, in some cases, by a detonator). The most common of these mixtures, of course, is aluminum and iron oxide.

I've experimented with a few other different mixtures. Anhydrous CuCl2 and aluminum is easy to ignite, though not terribly vigorous. I was able to wrap some CuCl2 powder in aluminum foil to make a tube and ignite the tube at one end with an alcohol burner. Combustion progressed with a small amount of pinkish flame (I would have expected green or blue, but it was pink) and considerable smoke, with solid copper being deposited. CuCl2 and 300 mesh aluminum powder burned quickly.

Flour-fine CuO from a ceramics supplier burned with extreme vigor with 300 mesh aluminum in a stoichiometric ratio. I ignited one charge of about 30 grams at night with a hot aluminum/sulfur ignition mixture. The thermite mixture was in an aluminum can with the top cut off and the igniter laid on top. The CuO/Al burned in a fraction of a second with a hearty "whump!" and shot glowing debris (likely the igniter slag) 10 meters in the air.

A 50 gram charge of the same mixture was initiated in the daytime with 2 grams of HMTD. There was a satisfying flash and explosion, and a large cloud of brownish smoke (vaporized copper mixed with aluminum oxide) rose above the test site. It is interesting that this mixture yields *no* permanent gases at STP yet exploded with sufficient force to make the plastic stand holding the charge vanish without a trace.

I have oxides of tin and chromium on hand, which I hope to try at some point in the future. I would also like to try lead salts/oxides, though I fear excessive sensitivity with these, and also with silver salts/oxides, though I fear sensitivity *and* price with them.

Have any other experimenters here wandered off the beaten path of "standard" thermite?

CuCl2 plus aluminum looks like an interesting reaction... would it be possible to carry out the reaction in a test tube and condense the smoke on a cold finger to obtain anhydrous aluminum chloride?

Copper (II) Chloride

JJay - 13-12-2015 at 04:23

I started making some copper (II) chloride thermite out of OTC materials. First I dissolved 100.00 g of CaCl2 monohydrate in 200 mL of water. I checked the specific gravity of the solution to ensure that I did in fact have the monohydrate salt, and it matched up very closely to what I expected. Then I dissolved 193.55 g of copper sulfate pentahydrate in 700 mL of water. With strong stirring, I added the calcium chloride solution in 10 mL portions. Gypsum precipitated out of solution with a green color that quickly dissipated. Towards the end, the solution became too sludgy for my stirrer, so I had to mix it with a PTFE-coated paddle. I let the reaction mixture stand overnight in the hopes that it would settle but afterwards could only pour off a couple hundred mL of solution, so I vacuum filtered and discarded the clay-like gypsum filter cake after washing it with 100 mL of water. The cyan-colored filtrate did not react any further with CaCl2 solution, but it does etch aluminum pretty vigorously, depositing powdered copper. Now I'm going to simply evaporate the filtrate to dryness and bake it in an oven to obtain anhydrous copper (II) chloride.

Update: As the water evaporates, the solution is becoming turbid with a small amount of precipitate... I assume this is probably gypsum, so I'll filter when I determine that the solution is saturated with copper (II) chloride.

It occurred to me that I can moderate the rate of reaction between copper (II) chloride and aluminum by changing the size of the aluminum particles and possibly by introducing an impurity into the copper (II) chloride (sodium chloride, for example). The reaction looks extremely vigorous in YouTube videos, and it's not going to do me a whole lot of good if the aluminum chloride just escapes.

[Edited on 13-12-2015 by JJay]

glymes - 22-5-2016 at 10:34

PtO/Mg mixtures are supposed to detonate extremely violently.

Dornier 335A - 23-5-2016 at 00:57

Sounds like bullshit. Please provide a reference - if you don't have one, don't post your ideas as facts.
PtO contains 7.5% oxygen by weight, so the thermite won't contain much energy...

[Edited on 23-5-2016 by Dornier 335A]

glymes - 23-5-2016 at 03:34

I thought that a less reactive oxide and a more reactive metal makes for a more powerful thermite?

PHILOU Zrealone - 23-5-2016 at 04:57

Quote: Originally posted by glymes

I thought that a less reactive oxide and a more reactive metal makes for a more powerful thermite?

No you need a more reactive metal oxide and a more reactive metal...to speed up the reaction.
CuO and Al is famous.
PbO2 and Mg should do.
PbO2 and Al should do.

XeO3 and Mg or Al would be interesting although not a thermite in stricto senso.

Metacelsus - 23-5-2016 at 07:50

Those are more like flash powder, instead of thermite. I once tried CuO and aluminum thermite (stoichiometric mixture, both finely powdered), and it exploded. I know PbO₂ (or also Pb₃O₄) with aluminum or magnalium is used to make crackling fireworks, so the mixture is quite energetic.

Stibnut - 4-11-2016 at 05:27

I tried a fun experiment a couple of days ago: a thermite made of lithium and silicon dioxide. I just placed a ~0.25 g chunk of lithium on some silica beads, in a cheap silica crucible I didn't mind losing, and lit the lithium on fire with a torch. It doesn't need to be powdered because it will melt as it burns, igniting the SiO2 and setting off the thermite within a few seconds.

It's definitely a vigorous reaction, with lithium's deep red flame making it especially pretty. I repeated this one more time with the same result. I wouldn't say it's any more explosive than CuO/Al thermite, though small pieces of unreacted lithium do go flying and will (unlike the full-sized chunk of Li) explode on contact with water. Goggles and face shield highly recommended. Now I have a crucible with an interesting looking lump of unreacted silica plus elemental silicon fused into it.

[Edited on 4-11-2016 by Stibnut]

Theoretic - 30-12-2016 at 08:58

Quote: Originally posted by glymes

I thought that a less reactive oxide and a more reactive metal makes for a more powerful thermite?

The oxide of a less reactive metal makes for a more powerful thermite, because it holds the oxygen with less conviction and the norm reactive metal can combine with it easily (or, in case of gold oxide, it would even release energy as it releases oxygen!)
For copper compounds, they are generally very reactive towards aluminium. I once made an Al foil - partly anhydrous CuCl₂ burrito, literally power laying on the foil and scrolled up into a cylinder, and this ignited with heating from a candle! I'm not sure if the water helped (catalyzing the combustion like it catalyzes the reaction of CuCl₂ and Al in solution, hydrocarbon flames, Na-Cl₂ flames and many others), or if it hindered by absorbing heat with its evaporation.
Edit: remembered water also sets of Al - I₂, so up to a certain amount it must be helpful in general, among other things by being a mind of 'flux' by creating a way for reactant species to cross from grain to grain without having to evaporate.

[Edited on 30-12-2016 by Theoretic]

James Ikanov - 31-12-2016 at 19:08

Something interesting I just read that may apply to those of you using MnO2 type thermites....

https://medicine.wustl.edu/news/low-levels-manganese-welding...

I'm not sure if it's relevant to everyone or even anyone but it seems like something worth throwing out there where it's visible for anyone it might effect.

tsathoggua1 - 13-4-2017 at 13:37

Has anyone experience with Mn(OH)2-Mg or Mn(OH)2/Al thermites? Been wanting to reduce some manganese hydroxide using either Mg fine dust or have some <~30 micron Al. Is this known to be violent or explosive? because a slower burn is desired in order to trap the results in a crucible whilst burning and retain the Mn, the point of the exercise.

Likewise, with these reductants and colloidal SiO(H)2.

PHILOU Zrealone - 14-4-2017 at 18:31

Quote: Originally posted by tsathoggua1

Has anyone experience with Mn(OH)2-Mg or Mn(OH)2/Al thermites? Been wanting to reduce some manganese hydroxide using either Mg fine dust or have some <~30 micron Al. Is this known to be violent or explosive? because a slower burn is desired in order to trap the results in a crucible whilst burning and retain the Mn, the point of the exercise.

Likewise, with these reductants and colloidal SiO(H)2.

The idea to use hydroxides into Al or Mg thermites is for obvious reasons extremely dangerous...
-->hot burning composition (>2000°C) + water as product = explosion of H2O (gas) spreading burning red hot metal all over the place and at a relatively big distance...

tsathoggua1 - 16-4-2017 at 09:30

Decided to roast it, thanks for the quick tip.

Anyone ever done an MnO2 thermite? Question is, due to the reactivity of Mn, will it survive, and would a (lidded) carbon crucible survive the experience? and how difficult is it to ignite? I've always found bog standard Fe oxide/Al type thermites rather difficult to get going.

Mainly asking due to the rather odd reactivity of copper oxide thermites, Mn being a somewhat out of the usual range, I'd like some idea of its reactivity before initiation. The end goal is actually collecting the Mn, rather than simply a pyrotechnic display.

Would addition of a little sulfur to a small surface area suffice to allow initiation from the outside (assuming the lid is tightly clamped on, with a bit of disposable crap wood to avoid melting the clamp (these have copper plated steel end plates, ideally initiation from the outside of the crucible would be good, elsewise I'd have to initiate it with a piece of Li strip meaning gutting a battery (I've got some better quality Li, but thats kept in a sealed bag of inert gas, presumably argon, in a jar containing some anhydrous CaCl2 and Mg powder to absorb H2O and oxygen respectively, most of it already having been displaced with dry argon. And I'd sooner not open that, I'm saving it for the next time a large birch-benkeser reduction is on the menu, or something similar, so all 20-25g can be used at once, storage being a pain in the ass.

I find the foils in batteries work well for initiating thermites, and damned if I don't have a huge bag full of e-fag batteries that have gone down the shitter, so to speak. Damn things have a remarkably high attrition rate. Although at least when they fail charged they are good recycling material. (as if I haven't spent enough time filleting batteries of late, was up all night last night doing just that)

[Edited on 16-4-2017 by tsathoggua1]

Bert - 16-4-2017 at 22:45

If you ignite an Aluminum/Manganese dioxide thermite in a sealed crusible, it will probably EXPLODE.

The Manganese comes off as a GAS. Not a well mannered liquid metal- LOTS of very HOT gas, you can use this reaction as a rocket fuel with an ISP similar to black powder.

There are descriptions of techniques that have been used by a member to collect Manganese metal from such reductions posted here, search a bit.

tsathoggua1 - 17-4-2017 at 02:27

Did it in the open, and wasn't greatly surprised to find that there wasn't a collectible quantity of elemental manganese. I don't do pyro, can't afford to get clocked doing that stuff, the thermite rxn is more or less an exception, used for E.g cutting, welding, and harvesting metals from oxides.

MnO2/Mg proved too difficult to ignite on its own, but the mixture, sensitized with a little sulfur in a localized area (the idea being the thermate ignites the thermite with as little sulfur/sulfide contamination as possible) does indeed go off bloody fast. Hadn't quite realized HOW fast though. MnO2/Mg/S thermate goes off like flash powder and is sensitive enough to ignite with a blowtorch flame exposure for a second or two, yet MnO2/Mg (can't remember the mesh size, but fairly fine.

Another attempt made was pyrolysis of manganese formate and acetate in an argon-purged stoppered tube in the hope of forming something akin to pyeophorus of lead or pyrophoric iron nanopowder akin to the products of pyrolyzing the corresponding tartrates (didn't have any tartaric acid to hand so I went with the formate and acetate salts. Next, the ascorbate will be tried, Vit.C being a reducing agent might help, would be interesting to try anyway. As will the cutrate,

Acrid fumes were driven off under heating in the air of a sample, whilst a dark, tarry substance, doubtless generic organic residues from pyrolysis of the organic portion of the salt, but no luck, even when heated sufficiently to break the test tube (I've another order coming of test tubes and this one was intractably mucky so sacrificing it was fine,

tsathoggua1 - 17-4-2017 at 02:41

Interesting that people say PbO2/Al thermites are meant to be energetic, U dud use it in a thermite once, ignition with a strip of lithium foil in lieu of magnesium as a fuse, and it was decidedly sluggish, onlu a few sparks and a slow, dull red glowing reduction giving elemental lead

Strange problem with MgAl-red iron oxide thermite

Elemental Phosphorus - 24-5-2017 at 16:07

Today I ignited about 600 milligrams of thermite made with 200-325 mesh magnalium and red iron oxide (pottery grade, extremely fine, I can post a photo if necessary). Much to my surprise, it did not deflagarate like traditional Fe2O3/Al thermite, rather it deflagarated extremely fast (for thermite, slower than flash powder), and on analysis of the video the flash lasts ~8 frames. Can anyone provide insight as to why this happened? I mean, 4 of the frames are a completely yellow-white screen. That is simply not consistent with what I have seen of iron oxide thermite. Any comments? Thanks.

ShotBored - 24-5-2017 at 16:51

What was your ratio of mag-al to Fe2O3?

Elemental Phosphorus - 24-5-2017 at 17:42

250 milligrams of magnalium and 350 milligrams of red iron oxide.

greenlight - 24-5-2017 at 23:53

I have done some tests with magnalium thermite before and took photos.
I had a similar ratio to the one you list to start and it deflagrated very fast mainly throwing red hot metal all around and slightly charring what it was in contact with.
Results from testing in 5 gram amounts were:

2:1 Fe2o3:Mg/Al = Slightly slower but still too fast burning. Nearly no slag left.

3:1 Fe2o3:Mg/Al = Much slower burn rate 3 seconds) leaving some red hot slag.

4:1 Fe2o3:Mg/Al = Even slower burntime (5-6 seconds) leaving a lot of red hot slag behind.

I found it to be about perfect between the two last ratios. Here are two pictures of the tests midburn that I found. The left is the ratio similar to yours and the right is about 4g iron oxide to 1.2g Mg/Al.

[Edited on 25-5-2017 by greenlight]

Screenshot_2017-05-25-15-43-00.png - 2.2MB

[Edited on 25-5-2017 by greenlight]

PHILOU Zrealone - 25-5-2017 at 00:40

Quote: Originally posted by Elemental Phosphorus

Today I ignited about 600 milligrams of thermite made with 200-325 mesh magnalium and red iron oxide (pottery grade, extremely fine, I can post a photo if necessary). Much to my surprise, it did not deflagarate like traditional Fe2O3/Al thermite, rather it deflagarated extremely fast (for thermite, slower than flash powder), and on analysis of the video the flash lasts ~8 frames. Can anyone provide insight as to why this happened? I mean, 4 of the frames are a completely yellow-white screen. That is simply not consistent with what I have seen of iron oxide thermite. Any comments? Thanks.

Magnesium si more reactive than Aluminium so the mix ignites faster and easier...the activation energy is thus lower.

Magnesium burns brighter than Aluminium so your photo or video camera sensor did a (over)saturation of its sensor and had not the time to adapt for brightness.

Elemental Phosphorus - 25-5-2017 at 03:58

That makes sense, thanks. I was going to guess that since I had not previously dried the red iron oxide, it was a steam explosion. But that didn't really make sense, since there was a very bright flash, and the oxide didn't seem *too* wet. I'll post some freeze-frames later today. Anyhow, I'm glad I only made 600 milligrams, since I did not expect a fast deflagaration. I suppose that I can take away the lesson to always test any sort of pyrotechnics or energetic compositions in small quantities.

PHILOU Zrealone - 25-5-2017 at 12:04

Quote: Originally posted by Elemental Phosphorus

That makes sense, thanks. I was going to guess that since I had not previously dried the red iron oxide, it was a steam explosion. But that didn't really make sense, since there was a very bright flash, and the oxide didn't seem *too* wet. I'll post some freeze-frames later today. Anyhow, I'm glad I only made 600 milligrams, since I did not expect a fast deflagaration. I suppose that I can take away the lesson to always test any sort of pyrotechnics or energetic compositions in small quantities.

Yes prior small testing is a must not only once, but everytime a parameter changes...moisture, new ingredient or batch, different mesh, different temperature, different confinement,...

And when scaling up...it is a good idea to do it by slow increments for safety considerations...even a simple scaling up factor 2 has lead to casualities onto industrial plants or on lab reactions process...via unsuspected side-reactions with a lower minor thermodynamic kinetic at one scale but higher and major at double scale...

Photos, as promised

Elemental Phosphorus - 25-5-2017 at 13:26

Here are the photos, as I promised:

Edit: I chose to omit the entirely white frames since those don't really help.

[Edited on 25-5-2017 by Elemental Phosphorus]

Dornier 335A - 26-5-2017 at 01:57

There's another important difference between magnesium and aluminium: the boiling point. Al boils at 2470°C and Mg at 1091°C, which means that magnesium based thermites produce gas unlike aluminium based ones.

Magnalium/Sm2O3 thermite

kratomiter - 6-7-2017 at 07:31

Here is a photo of a magnalium/Sm2O3 thermite. It burns slowly with a strong white light light, leaving a surface of what seems Al/Mg/Sm oxide (it gets oxidized easily when exposed in the air) and samarium dust inside. Also it emits white fumes, maybe Samarium?

[Edited on 6-7-2017 by kratomiter]

Deluxbert - 19-1-2018 at 07:30

MnO2 + Mg is another one of those "Thermites" that explode more than they burn. Never tried using Al but thats a possible way to get Manganese metal.

And like James Ikanov said. Breathing in Manganese is no good. It makes orange mushroom clouds.

[Edited on 19-1-2018 by Deluxbert]

Alidada - 8-11-2018 at 03:15

Hi everyone.

I am interested in ways you can make glass out of other chemicals and how you can join it with chemical reactions.
Chemical reactions for joining that I am thinking about are thermite reactions.
I did find some articles about using nanothermite in joining non similar materials.

Could there be some additives that you can add to Al/SiO2 thermite mix so that Silicon produced oxidizes and will not form elemental silicon?

Reason I want to do this is that I want to produce glass microfluidic chips.

j_sum1 - 8-11-2018 at 03:32

Welcome to SM, alidada.
Your question is not really a thermite question. Glass is an oxide and, as such, is a potential reactant rather than the product of a thermite.

My recommendation is to search the board and see what you can find that relates to your question. If you don't find the answers you seek, it would be better to start a new thread.

wg48 - 8-11-2018 at 05:52

Quote: Originally posted by Alidada

Hi everyone.

I am interested in ways you can make glass out of other chemicals and how you can join it with chemical reactions.
Chemical reactions for joining that I am thinking about are thermite reactions.
I did find some articles about using nanothermite in joining non similar materials.

Could there be some additives that you can add to Al/SiO2 thermite mix so that Silicon produced oxidizes and will not form elemental silicon?

Reason I want to do this is that I want to produce glass microfluidic chips.

The slag produced by common thermites is a form of glass. I guess it would be possible to adjust the composition of the slag by adjusting the composition of the starting materials. So to get a soda lime glass the thermite would have to start from sodium and calcium metal, silicon (or the oxide) and iron oxide as the oxidant. The slag (glass) would float on top of molten iron. There are probably other types of glass that would be more compatible with the thermite process. However the slag tends to cool quickly and trap gas bubbles and fracture. It would also be contaminated by iron. Its probably not impossible to do with lots of experimentation.

If your just wanting to glue glass sheets together and need the chemical resistance of glass then fusing or ceramic glues can be used. There are also lots organic glues specific for glass including UV cured types if such organics are compatible with your fluidics.

Thermite Pellet Forming

Ghass1974 - 1-2-2019 at 15:32

Hello everyone,

I am new to this topic. I am looking for a Teflon Resin that comes in a liquid form then upon mixing with thermite ingredients such as iron oxide and aluminum, with a hardener; it will harden to a pellet.
Is there a PTFE resin that I can use, if not , is there anything else?

Thank you
Ghass

Rocinante - 17-4-2019 at 10:55

Has anyone any experience with a thermite mixture that burns hot (above 1500°C) has sufficient energy density (above 2.5 kJ/g and at least 7 kJ when pressed close to 3 g/cm^3) while producing a very viscous/semi-molten mass?

My first guess/attempt would/will be SiO2/Fe2O3 thermite 1:1 pressed close to 3 g/cm3 if possible.

The goal is to produce pellets that have high steel melting/damaging capability. While regular thermite can be pressed to impressive 4.9 g/cm3 (loose powder has 0.7) and energy density above 20 kJ/cm3 and low burning speed of 4 mm/s with little spray - it has one draw back - the molten iron is quite liquid and it tends to pour quickly out of the first hole it creates, thus having not-so-great anti-steel capability.

MineMan - 18-4-2019 at 01:31

A thermite with silicon as a fuel? Since silicon will oxidize into SIO2. Good question man. That’s a tough one. Can you describe the purpose more? Will these be shot at the steel?

All anti armor munitions are made to just punch a hole really... have no idea how you would damage a large area of steel.

[Edited on 18-4-2019 by MineMan]

Rocinante - 19-4-2019 at 10:30

No. I mean SiO2/Al + Fe2O3/Al mixture, 50:50 by mass.
Sillicon thermite is notoriously solid and difficult to ignite because it burns only around 1700°C and the sillicon produced freezes into solid at 1500°C which would be ideal for my purpose but the energy density is low (2000 kJ/kg, about 4000 J/cm3) compared to 12 kJ/cm3 for only mildly (3 g/cm3) pressed Fe2O3 thermite

I envision two applications, a heating pellet 4 cm in diamater inside a heat resistant casing placed on a piece of steel and a wide-flange column destroyer, an [ shaped piece of heat resistant casing is placed between the flanges of the column and the mixture heats it to failure (850 degrees and above for a short section), however the mixture needs to be solid enough not to pour out of the bottom once the column starts to - slightly - deform (650°C).

I'm going to try the 50:50 mixture in the next few weeks, anyway I though about 25 % SiC and 75 % normal thermite, a large part of the SiC shoudl survive at the burn front in a solid state - giving the iron more of a gel form (I hope).

MineMan - 19-4-2019 at 13:42

could try that. Curious to know results. Unfortunately there does not seem to be a lot published on thermite. I think a boron oxide plus mg or mg Al could work well. Boron also has a high melting temp and is a metalliod like silicon, but should hold more oxygen and maybe more energy? I just wouldn’t think a gel would do that much more damage then a liquid. I think it will do less. As soon as it cools just a little it won’t want to fall into holes thus it will just sit and not continue to burn through.

Have you seen a thermite lance. That would work better. They use copper oxide and direct the stream of pressurized molten metal onto the target. You need to add something that produces gas like CuO and add a nozzle.

They have handheld lances the size of flares that are impressive.

Rocinante - 25-4-2019 at 12:34

regular Fe2O3 thermite produces plenty of iron vapor (7.5 % by weight in adiabatic conditions) and expanded air/humidity.

I tested 80 g of SiO2/Fe2O3 thermite 40:60 pressed to 1.2 density and it worked great the initial flame is as fast as normal iron thermite pressed to that density but less energetic
then if created a semi-molten white hot mass that reacted for 90 s - sand particles with molten aluminium
great, so it would absolutely destroy a column - no leakage possible
the penetration power is not that great, in fact it frote just after penetration - pluging the holes with iron/sillicon/sand mixture... like an icicle

MineMan - 26-4-2019 at 11:39

That’s what I was afraid of Rocinanate.

Bert - 26-4-2019 at 11:53

Quote: Originally posted by MineMan

You need to add something that produces gas

Teflon powder (PTFE) has been used in some torches both as an additional oxidizer and to provide gasses which "pressurize the effluent".

Don't burn your fingers-

Vomaturge - 26-4-2019 at 20:55

Whether you believe the sociopolitical theories this guyputs forward or not, I think he proves that a narrow stream of moving thermate will get more molten material in per unit area with decent heat transfer, instead of solidifying alumina and the like on the target and insulating it to the point that the heat slowly dissipates.

Incidentally, I think part of the spattering and gassing of thermites is from oxygen dissociation. It won't stay completely tied up in oxides at those temps.

Oh, and hi Bert! Nice to have you back.

Rocinante - 27-4-2019 at 00:27

Yes. That's what I saw and what inspired me. I like the idea of destroying columns with something else than noisy, fragmenting plastic/melt cast.
The problem with his method is that you will need some modifications or else a column under load can re-weld together. Also, his devices are needlesly big. You can easily press thermate to higher than 2.5 density on a press, he seems to be using non-pressed thermate which is likely 0.7 just as unpressed thermite.
Also, cutting is fine but heating it to failure (900°C over a small section) via my sillicon/iron thermite is more fun.

Also, any ideas on PTFE/Boron or PTFE/Be? Seems like a cool idea. I found only PTFE/Boron papers.
Also, PTFE/Be + 15 % PETN/ETN/HMX might be a nice explosive, I know that PTFE/AL + 15 % HMX has been tested an it is an all-right explosive.

[Edited on 27-4-2019 by Rocinante]

Vomaturge - 27-4-2019 at 06:16

Quote: Originally posted by Rocinante

Yes. That's what I saw and what inspired me. I like the idea of destroying columns with something else than noisy, fragmenting plastic/melt cast.
The problem with his method is that you will need some modifications or else a column under load can re-weld together. Also, his devices are needlesly big. You can easily press thermate to higher than 2.5 density on a press, he seems to be using non-pressed thermate which is likely 0.7 just as unpressed thermite.
Also, cutting is fine but heating it to failure (900°C over a small section) via my sillicon/iron thermite is more fun.

Also, any ideas on PTFE/Boron or PTFE/Be? Seems like a cool idea. I found only PTFE/Boron papers.
Also, PTFE/Be + 15 % PETN/ETN/HMX might be a nice explosive, I know that PTFE/AL + 15 % HMX has been tested an it is an all-right explosive.

[Edited on 27-4-2019 by Rocinante]

A: cool! (So long as nobody melts a real building, that is) glad you can think of improvements to that design. Maybe setting it at 45 degrees to the vertical would help? You'll need about 41% more, but combined with simultaneous ignition on multiple sides and members, welding should be nearly impossible.

B:I think LiD in a U-238 case will give longer positive phase in the open, more brisance if tamped, and cost less and create less toxic aftermath, at least per unit of energy released:
Cbrvusa2-262x265.gif.jpg - 24kB

Edit: Boron might be kind of expensive, but at least it won't be so toxic. It might be a good idea given fine enough particles and good mixing. Boron has fair density and low atomic weight, so you would need less of it to reduce a given amount of ptfe.

[Edited on 27-4-2019 by Vomaturge]

Rocinante - 27-4-2019 at 07:13

The oral LD50 for a man is like 7 g of BeF2. Not that much. Boron is kinetically trapped.

MineMan - 27-4-2019 at 10:07

Quote: Originally posted by Bert

Quote: Originally posted by MineMan

You need to add something that produces gas

Teflon powder (PTFE) has been used in some torches both as an additional oxidizer and to provide gasses which "pressurize the effluent".

Don't burn your fingers-

Bert!

Rocinante - 28-4-2019 at 12:45

I was somewhat wrong about the SiO2/Fe2O3 thermite, all it took was a slight hit and it came out, it burned through all 3 layers of metal can(s) with a surface area almost equal to the can it was in. So the high-viscosity mass thing worked, though you need like 80 g to burn a 45 mm diamater hole through like 0.5 mm of steel (about 5 g) - not that bad but not amazing.

MineMan - 28-4-2019 at 15:41

Quote: Originally posted by Rocinante

I was somewhat wrong about the SiO2/Fe2O3 thermite, all it took was a slight hit and it came out, it burned through all 3 layers of metal can(s) with a surface area almost equal to the can it was in. So the high-viscosity mass thing worked, though you need like 80 g to burn a 45 mm diamater hole through like 0.5 mm of steel (about 5 g) - not that bad but not amazing.

I think that is not so good. You need pressure. Bert is right. Look up underwater cutting thermite formulations. PTFE and Be... why? Be creates massive energy when matched with oxygen, but not as much when paired with F. Also. Be is toxic when not bonded to F, and expensive.

My gut (and research) tells me CuO,PTFE, and Al would be a good start. Pressed and with a nitrocellulose binder to slow the burning and to produce gas.

Don’t underestimate PTFE, it might be one of the best but overlooked oxidizers... tell me what other oxidizer is 76 percent weight active???

Rocinante - 29-4-2019 at 08:10

I was looking for a hole creator and sillicon/iron thermite proved itself.
Now it is time for cutter type devices.
Yes, CuO is one of the most energetic thermites (comparable to iron thermite) and the fluidity of molten copper will help (m.p. of only 1300 K or so). There is no need for outside gas as plenty of the copper is turned into gas by the reaxtion itself. Also, controlling the mixture by precise ratio and density is better than adding anything else which ony makes the process more time-expensive.
I'll try copper thermite cutting devices in late july or so. I might get a small wide flange column.

Herr Haber - 2-5-2019 at 06:48

Quote: Originally posted by MineMan

Have you seen a thermite lance. That would work better. They use copper oxide and direct the stream of pressurized molten metal onto the target. You need to add something that produces gas like CuO and add a nozzle.

They have handheld lances the size of flares that are impressive.

Never heard of these but didnt you mean themal or thermic lance ?
Just a hollow iron / steel tube with an oxygen bottle really.

Rocinante - 2-5-2019 at 08:33

It's called Tec Torch and there are others like Fire Pen.

MineMan - 2-5-2019 at 19:44

Quote: Originally posted by Herr Haber

Quote: Originally posted by MineMan

Never heard of these but didnt you mean themal or thermic lance ?
Just a hollow iron / steel tube with an oxygen bottle really.

Yes. I meant that and a tech torch which is a different concept.

Vomaturge - 2-5-2019 at 23:27

I just looked up tec torch and watched a promotional video for it. Between 1:47 and 1:59 we see that for one thing the melting action is focused to cut all the way through a rod or plate in a very limited area (less than the rod's diameter in most cases) Incidentally, the safety datasheet says the thermite is copper and molybdenum oxides, aluminum and magnesium.

Also, the recoil force is "less than 5 lbs" (~20 Newtons) I don't know how much less than 5lbf it is, but clearly the thermite products are moving fast. At very most, I'd say the cartridges are 10cm long and 2 cm in radius. With a loading density of 3, that is still under .4kg of thermite. And if the force is only 10 Newton for 2 seconds, that gives an exit velocity of at very least 50 meters per second and likely far more. That makes sure that the little section of target directly in front of the nozzle gets hit by a much larger amount of reaction products, and that slag is stripped away as fast as it forms. The big question is, how do they make a nozzle which creates such a directional jet, while not being melted out of shape itself?

To copy it without the special nozzle, perhaps you could use a long thin bar of thermite (or cast CaSO4&Al) and just feed it toward the tatget as it burned up. Ah, if only I had aluminum powder...

[Edited on 3-5-2019 by Vomaturge]

Rocinante - 3-5-2019 at 11:03

Some issue with legislation in your country? I feel your pain.

But yes, having someone on SM experimenting with thermite cutters would have been awesome.

I actly have a paper where all thermites/intermettalic compounds are listed.

https://www.osti.gov/biblio/372665

The video by Jonathan Cole shows a simple steel tube aimed at a steel column cutting it. Some graphite coating might help, too.

[Edited on 3-5-2019 by Rocinante]

Rocinante - 8-5-2019 at 11:32

This patent: https://worldwide.espacenet.com/publicationDetails/originalD...

They are able to burn a 8.5 cm hole through 1.27 cm thick steel plate (72 ml of steel, 560 g of steel) with 1.6 kg of thermate in a 10 cm wide and 16 cm high device. The device is coated with graphite.

Microtek - 10-5-2019 at 02:40

How about using a hollow core design? This would shield the outside cylinder from the heat, and also provide a kind of nozzle (as well as a much larger combustion area). You would probably need to tweak the formula to avoid bursting the assembly.

Rocinante - 11-5-2019 at 12:01

they describe that in the patent, the filling has many channels for the gases to escape. The graphite coating is enough to protect the tube, no problems there.

Rly, 3 g of thermate per gram of melted/blown away steel is impressive. It takes something like 1 - 1.5 kJ/g to heat and melt steel and 3 g thermate has about 10 kJ of energy (less than pure thermite) so you're looking at ~ 15 % efficiency - and that is quite impressive for such a quick process and "low-tech" device.

georgef2545 - 30-11-2019 at 13:50

Quote: Originally posted by vulture

How about CaC2/Fe2O3? The formation of CaO should gives quite a good enthalpy.
Not to speak of KMnO4/CaC2.....

I wouldn't call that a classic thermite perhaps, but it sure would be very interesting!

Superfine termite

Piroz - 28-2-2021 at 16:06

Few years ago I had some experiments with Fe3O4/Al thermite, I found it have very interesting properties. As you know this type of thermite is hard to ignite but finely powdered is very easy to do it- just by touchung with flame from match or lighter etc. In large amounts it burns really fast however in tiny amounts it can "explode" giving enormous amount of light (it blinded me for several seconds) and sparks shower. Here the video with tiny amount of thermite burned on match in slow motion:

https://youtu.be/_Mp24ePmUiM

And here the second video with thermite compilation, with Fe3O4/Al, except first burning termite. If particles are bigger but not too much also greater amounts of thermite can explode. After slightly heating in flame thermite starts to glow more and more and suddenly explodes.
(in the video finely powdered thermite form 1:30 to end):

https://youtu.be/gsdWFBVx2fc

Linus1208 - 7-6-2021 at 04:57

Quote: Originally posted by Polverone

Flour-fine CuO from a ceramics supplier burned with extreme vigor with 300 mesh aluminum in a stoichiometric ratio. I ignited one charge of about 30 grams at night with a hot aluminum/sulfur ignition mixture. The thermite mixture was in an aluminum can with the top cut off and the igniter laid on top. The CuO/Al burned in a fraction of a second with a hearty "whump!" and shot glowing debris (likely the igniter slag) 10 meters in the air.

A 50 gram charge of the same mixture was initiated in the daytime with 2 grams of HMTD. There was a satisfying flash and explosion, and a large cloud of brownish smoke (vaporized copper mixed with aluminum oxide) rose above the test site. It is interesting that this mixture yields *no* permanent gases at STP yet exploded with sufficient force to make the plastic stand holding the charge vanish without a trace.
"standard" thermite?

A mix of anhydrous copper sulfate and magnesium (45µm) in a 13:2 or 20:3 ratio reacts very violently, I discovered it when I wanted to make CuO / Magnesium Thermite (which doesnt react as violently) but didn't have CuO on hand.

Even though the CuSO4 wasn't that fine (Idk how much exactly but similar to fine sand, maybe a bit finer) ~25g of it unconfined exploded very violently when ignited by a plain old sparkler (--> attachment).

Attachment: IMG_0523.TRIM (convert-video-online.com).mp4 (4MB)
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Grizli7 - 1-9-2021 at 11:09

Pb3O4+Al powder my favorite childhood composition . A huge number of compositions. What category do you want the composition: primary ignition, thermite itself, shock, grating, electro-ignition, what reagents are there?

Linus1208 - 20-11-2021 at 06:15

Quote: Originally posted by Linus1208

So I noticed I completely miscalculated the ratio (it was still explosive though). The stoichiometric ratio would be 4:3 anhydr. CuSO4/Mg. In this ratio small amounts (1/10ths of a gram) deflagrate quite strongly, definetely comparable with permanganate flash. A knife edge amount loosely confined in aluminium foil, ignited by heating in a flame will go off with quite a good bang. The problem with this mixture still is that it's hygroscopic, so it needs to be stored air tight to be usable for more than 2 or 3 hours.

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