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MineMan
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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.
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Rocinante
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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
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MineMan
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That’s what I was afraid of Rocinanate.
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Bert
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Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
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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-
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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Vomaturge
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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.
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Rocinante
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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]
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Vomaturge
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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:
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]
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Rocinante
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The oral LD50 for a man is like 7 g of BeF2. Not that much. Boron is kinetically trapped.
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MineMan
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| Quote: Originally posted by Bert |
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!
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Rocinante
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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.
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MineMan
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| 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???
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Rocinante
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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.
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Herr Haber
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| 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.
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Rocinante
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It's called Tec Torch and there are others like Fire Pen.
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MineMan
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| Quote: Originally posted by Herr Haber | | 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. |
Yes. I meant that and a tech torch which is a different concept.
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Vomaturge
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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]
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Rocinante
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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]
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Rocinante
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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.
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Microtek
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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.
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Rocinante
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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.
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georgef2545
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| 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!
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Piroz
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Superfine termite
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
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Linus1208
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| 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)
This file has been downloaded 420 times
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Grizli7
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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?
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Linus1208
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| Quote: Originally posted by Linus1208 |
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.
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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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