Sciencemadness Discussion Board

Exotic thermites & analogs

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Hey Buddy - 26-12-2022 at 12:52



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Conure - 7-2-2023 at 12:58

Has anyone had any luck with TH3 thermate? I tried it once and the performance was garbage. A quick fire that just left a burn mark on the test plate. Same amount of thermite would have left a small hole dripped through.

Thank you VERY MUCH

chloric1 - 8-2-2023 at 09:58

Quote: Originally posted by Hey Buddy  





I do appreciate it! I have a paid app CamScanner that I pay like $70 a year for since I constantly need to create various pdfs. I was able to load this piece by piece on there and merge them into one volume.














B(a)P - 8-2-2023 at 12:00

Quote: Originally posted by Hey Buddy  


1000+ pages of thermite tables




Thank you very much Hey Buddy!

knowledgevschaos - 10-8-2023 at 01:32

Hello everyone, I have a question and this seems like the thread to put it in. Someone here mentioned that aluminium-sulfur thermite is easier to ignite than the standard iron oxide thermite. thermite made from coarse aluminium powder is very hard to ignite, especially with the low quality sparklers. I had the idea to melt aluminium sulfur thermite made with a finer powder, and dip sparklers in it, to create a sparkler which would hopefully burn hot enough to light very coarse thermite. I am also aware that handling a molten thermite sounds like an incredibly bad idea, but the theory is that the melting point of sulfur is about 115 degrees celcius, and this is far below the ignition points of most thermites.
Does anyone have experience working with this?
Also, would the sulfur just oxidize the aluminium?
Lastly, some mixtures, like whistle mix, can detonate when molten. could this happen for a molten thermite?
Thanks everyone.

B(a)P - 10-8-2023 at 02:21

Quote: Originally posted by knowledgevschaos  
Hello everyone, I have a question and this seems like the thread to put it in. Someone here mentioned that aluminium-sulfur thermite is easier to ignite than the standard iron oxide thermite. thermite made from coarse aluminium powder is very hard to ignite, especially with the low quality sparklers. I had the idea to melt aluminium sulfur thermite made with a finer powder, and dip sparklers in it, to create a sparkler which would hopefully burn hot enough to light very coarse thermite. I am also aware that handling a molten thermite sounds like an incredibly bad idea, but the theory is that the melting point of sulfur is about 115 degrees celcius, and this is far below the ignition points of most thermites.
Does anyone have experience working with this?
Also, would the sulfur just oxidize the aluminium?
Lastly, some mixtures, like whistle mix, can detonate when molten. could this happen for a molten thermite?
Thanks everyone.


I have not tried this, but my prediction would be that it would not ignite below 500 C, so you may have some room to move there. Best to try it on a very small scale first. Also you will need to check that molten sulfur will not react with the perchlorate in the sparkler on contact when you are trying to coat it. Another option is a mixture of a perchlorate salt and aluminium bound in silicon sealant. It burns hot enough to ignite aluminium/iron oxide thermite.

[Edited on 10-8-2023 by B(a)P]

Linus1208 - 4-9-2023 at 08:44

Quote: Originally posted by knowledgevschaos  
Hello everyone, I have a question and this seems like the thread to put it in. Someone here mentioned that aluminium-sulfur thermite is easier to ignite than the standard iron oxide thermite. thermite made from coarse aluminium powder is very hard to ignite, especially with the low quality sparklers. I had the idea to melt aluminium sulfur thermite made with a finer powder, and dip sparklers in it, to create a sparkler which would hopefully burn hot enough to light very coarse thermite. I am also aware that handling a molten thermite sounds like an incredibly bad idea, but the theory is that the melting point of sulfur is about 115 degrees celcius, and this is far below the ignition points of most thermites.
Does anyone have experience working with this?
Also, would the sulfur just oxidize the aluminium?
Lastly, some mixtures, like whistle mix, can detonate when molten. could this happen for a molten thermite?
Thanks everyone.


I once experimented with an Aluminium-sulfur mixture, and it quickly melted through a stainless steel can, so I would say it is almost as hot as the thermite itself.
For mixtures of sulfur and metal powders, the ignition temperature is between 400-600°C.
https://www.researchgate.net/figure/gnition-temperatures-of-...
This paper doesn't list an aluminium-sulfur composition, but I doubt its ignition temperature would be significantly lower than the magnesium-sulfur mixture.
I haven't measured the temperature exactly, but from the combustion tests I have done, they seem to behave similarly in that matter.
When testing a large quantity of the Al-S mixture, I had a steam explosion happen, but I really don't think it could detonate on its own. But you should try it out in safe quantities before messing around with it.
One problem there could be is that it might be hard to form a homogenous mixture from the two.

Thermite notes and questions

knowledgevschaos - 16-10-2023 at 01:50

Hello everyone, I've done some more experimenting with thermites, and here are some potentially useful things I've noticed.

PLASTER THERMITE
While reading this thread I noticed some posts about a thermite containing only plaster of paris and powdered aluminium. On youtube there are some videos of the same thing, so I gave it a try. I mixed 2 grams of powdered aluminium (made by manually filing a bar of aluminium with a steel file, would not recommend!) with 4 grams of plaster of paris, the ratio used in the youtube video. I mixed it with enough water to get it to a toothpaste-like consistency, and let it set into a block. After a day or so, I baked it in the oven at 150 C for one hour, and then 200 C for another hour, to drive off any moisture. I tried lighting it with a sparkler, which failed, probably due to the large particle size of the aluminium. Then I tried lighting it with a pile of aluminium - sulfur thermite, as it is easier to ignite. the aluminium - sulfur lit, and the heat was enough to set fire to the plaster thermite, which burned for about 20 seconds with a brilliant and extremely bright white light. It was a lot brighter and more white than ordinary thermite which seems to burn more yellow. This was closer to the light of burning magnesium, but more intense, and it really was incredible. The slag smelled of hydrogen sulfide, probably because of the calcium sulfide in it. I was very impressed with this and I think it could definitely be useful, especially because it exists as a solid object and not a powder.

ALUMINIUM POWDER FROM BLENDING FOIL
I got sick of filing an aluminium bar for hours just to get a few grams of poor quality powdered aluminium, so I bought a cheap blender and shredded strips of aluminium foil in water. I didn't want to do it without a liquid, because of the explosion hazard and for fear of overheating the blender. I used oil in my second batch, to prevent oxidation and so that the mix would be thicker. I hoped that would let it blend better. I got a fairly coarse aluminium powder, with similar consistency to sand, which I washed with shellite to remove the oil. I haven't tested this oil batch yet but the batch made with water performed fairly well in an iron thermite. I made about 30g of ferric oxide - aluminium thermite in an 8:3 ratio, and lit it with the aluminium - sulfur thermite, lit by a sparkler. It burned quite slowly and failed to destroy a 1 mm iron plate, but it did burn, and produced many little blobs of iron. Although not very impressive, it is definitely good considering I made my aluminium in a blender.

LIGHTING THERMITE WITH ALUMINIUM - SULFUR
I've already covered this but it aluminium - sulfur definitely seems suitable for lighting coarser thermites where an ordinary sparkler doesn't seem to do the trick. The only problem is the presence of sulfides in the slag, which can produce hydrogen sulfide on contact with water. This, combined with the fumes the reaction produces, could attract unwanted attention, so I may leave this reaction alone for the time being.

Now for some questions.
Copper is known for having a blue flame colour, so why does copper oxide thermite burn with a yellow flash, and not a blue one? Is the spectrum of copper completely dwarfed by black body radiation or is something else happening? If so, is it possible to produce a coloured burning thermite? I think the a colour added to the brilliant white of plaster thermite could be quite spectacular.

I've given up on the idea of melting aluminium - sulfur thermite, but B(a)P mentioned binding aluminium with a perchlorate in silicone sealant. Is it worth attempting this with aluminium - sulfur thermite? What kind of silicone should be used?

I'm also thinking of combining regular ferric oxide thermite with plaster thermite, which would hopefully still have the ability to be cast into a brick, but also produce molten iron like regular thermite.

Finally, I think copper oxide thermite may also be a suitable igniter for coarser thermites. it seems easy to ignite from the little I've made, and I don't expect it to be explosive at all when made with my very coarse aluminium powder. Let me know if my assumption is wrong though.

Sorry for the massive essay everyone, and thanks for reading.

B(a)P - 16-10-2023 at 11:31

Thanks for sharing, you have made some interesting observations. I have never tried making a plaster thermite, I will give it a go at some point.

Quote: Originally posted by knowledgevschaos  


I've given up on the idea of melting aluminium - sulfur thermite, but B(a)P mentioned binding aluminium with a perchlorate in silicone sealant. Is it worth attempting this with aluminium - sulfur thermite? What kind of silicone should be used?


Get a sealant that claims to be 100% silicone sealant, no pigments or mould prevention. Something like this product Selleys Glass Silicone.

I have tried a number of different perchlorate/sulfur/aluminium/silicone blends, though never without perchlorate. I have tried both potassium perchlorate and ammonium perchlorate. Some of the compositions have been very energetic, as always with this sort of thing, start very small (<1 g) and scale up slowly.

EF2000 - 17-10-2023 at 23:27

Quote: Originally posted by knowledgevschaos  

Now for some questions.
Copper is known for having a blue flame colour, so why does copper oxide thermite burn with a yellow flash, and not a blue one? Is the spectrum of copper completely dwarfed by black body radiation or is something else happening? If so, is it possible to produce a coloured burning thermite? I think the a colour added to the brilliant white of plaster thermite could be quite spectacular.


It's hard to add color to hot-burning composition, even CuSO4+Mg burns with yellow flash (here, through last flash is kinda blue).
Thus, a lot of colored flame compositions have something added to cool the flame. Hexamine, for example. Also halogen donors help, cause halogenides of metals shine brighter than oxides.
So, you can try copper oxide thermite with a bit of hexamine + a bit of PTFE tape (don't breathe in reaction products!) or a bit of PVC (PVC glue for example)
And keep in mind that calcium in plaster gives orange flame, you may need to replace it with copper sulfate for clearer color

Conure - 21-10-2023 at 11:40

Has anyone tried using Si as the reducer? tried Si+CuO. It works nice.
https://youtu.be/_LyAF2BT-fQ?si=a4Bbw34utjK07f_E

knowledgevschaos - 1-1-2024 at 20:30

That's fascinating.
Where did you get your silicon? Does it come as a powder or did you grind it yourself? If so how? As far as I'm aware it's very hard.
I also saw your video on the tungsten thermite. I was speculating about it, but didn't think it was possible because of the melting point of tungsten. Do you think the reaction was above the melting point of tungsten or was it somehow produced as a solid? It seemed like a spectacular reaction like copper thermite. Do you think it was as violent?
https://youtu.be/elcp0QWkwYE?si=hWGr415vgupuJFaf

Conure - 16-1-2024 at 11:21

Quote: Originally posted by knowledgevschaos  
That's fascinating.
Where did you get your silicon? Does it come as a powder or did you grind it yourself? If so how? As far as I'm aware it's very hard.
I also saw your video on the tungsten thermite. I was speculating about it, but didn't think it was possible because of the melting point of tungsten. Do you think the reaction was above the melting point of tungsten or was it somehow produced as a solid? It seemed like a spectacular reaction like copper thermite. Do you think it was as violent?
https://youtu.be/elcp0QWkwYE?si=hWGr415vgupuJFaf

I buy Si powder rom pyrogarage.com. The book Thermitic thermodynamics states Al+WO3 in stoichiometric ratio reaches 3874k. I dont know if its true or if it makes liquid products, and I cant get anymore WO3. I think CuO thermite looks more violent.

More plaster thermite notes

knowledgevschaos - 29-2-2024 at 01:46

SPECULATION ON THE REACTION OCCURRING:
I figured that the aluminium was reducing the plaster into calcium sulfide in the reaction:
3CaSO4 + 8Al -> 3CaS + 4Al2O3
This would give an ideal ratio of 2.02:1, very close to the 2:1 that everyone uses, so this is probably the reaction that's happening. I don't know what role the water molecules in the calcium sulfate would play in the reaction though.
USING PLASTER THERMITE AS AN INCENDIARY:
I've pretty much given up on this. I've tried using circular "pucks" of the cast material with a hole in the center so that it can be ignited and burn from the inside out, hopefully channeling all the molten material onto the steel plate I've been trying to melt. Even using 50 grams of thermite (measured by the dry materials before water is added to cast it), It could not melt through even a 1 mm steel plate. I think that particles of oxides and sulfides becoming superheated creates the bright light, similar to limelight, without actually producing much heat. The other possibility is that the slag is a poor conductor of heat compared to the molten iron produced in standard thermite, so the heat of the reaction may not be getting transferred to the plate well enough. It might also be my poor quality aluminium powder slowing down the reaction. It could still be a good flare composition though, because it's very bright.
MIXED TYPE THERMITE:
I found this video by wheeler scientific on this.
https://www.youtube.com/watch?v=aVRRvMpov6E
It looks like a combined standard thermite and plaster thermite works better than plaster thermite alone. The ratio he used was 2:2:3 (plaster : aluminium : ferric oxide).
Does anyone have any idea how the best ratio might be determined? I want to try this with copper oxide too, as with my coarse aluminium it shouldn't explode.
THE WORLD TRADE CENTER:
A few people seem to think that this thermite was used to bring down the world trade center. Although it may have worked to cause enough damage, anyone who has worked with thermite knows that it is far too bright. If it were used, people would have noticed that the towers were shining brighter than the sun. Correct me if I'm wrong, but I thought I'd put that out there.
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