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Author: Subject: Exotic thermites & analogs
Mr. Wizard
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[*] posted on 10-8-2005 at 07:57


Quote:
Originally posted by cumbustion
Would Al foil ground up in a coffee grinder be fine enough for thermite?

Strictly speaking ,yes. Quite large particles will work, but they become increasingly more difficult to ignite. When your materials get to the size of rice grains you need an acetylene torch (or an equivalent) to make a molten pool of reacting components, then the reaction will proceed in a slow manner if the material can fall into the molten reaction zone. This is a good thing if you are trying to form a casting or get a large piece of metal. The finely ground material is easier to ignite, reacts more quickly, and has less time for the waste slag and metal to separate. A good analogy would be burning charcoal. A large chunk will ignite with sufficient heat, burn slowly and do safe, useful work. A fine powder, mixed with oxidizers, will burn quickly, and does a different sort of work.
A mistake I made was to use such small quantities of slow reacting thermite that I didn't get results. Using a 5cc pile didn't work with the material I was using, but making a 200 cc pile and starting with a torch achieved a very strong , but slow reaction.
I would try to keep both component's particle sizes about equal.




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halogen
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[*] posted on 9-12-2005 at 10:21


Osmium tetraoxide/aluminum thermite. Is that possible?



F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat with the evolution of chlorine.
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[*] posted on 9-12-2005 at 14:09


Liquid right? Or at least low melting point. It would probably react on contact.

Which reminds me, how about Mn2O7? :P

Tim




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neutrino
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[*] posted on 10-12-2005 at 05:30


I doubt it would work. OsO<sub>4</sub> has a very low boiling point (130*C), so it would boil off before it could react. Imagine Al/H<sub>2</sub>O thermite...

[Edited on 10-12-2005 by neutrino]
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smile.gif posted on 14-12-2005 at 02:51


To me everything is possible...everything depends on the speed of reaction...remember that the highly volatile halocarbons do stil react explosively with Al powder or with alkaline metals (initiation by shok or heat)...

So the fact OsO4 is a volatile compound wouldn't be a sufficient reason to say it shouldn't work...

Mn2O7 may on react on contact with Al like it would with any reducer/fuel ...and as Mn2O7 is sensitive explosive by itself...

:D:cool::D




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Mr. Wizard
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[*] posted on 14-12-2005 at 10:30


Be aware the oxide of this metal is very toxic, volatile, and expensive. :)
http://www.chm.bris.ac.uk/motm/oso4/oso4h.htm

I think the 'thermit' reaction might take place under very high pressures, over the melting temperature of Al , as in an explosion. The analogy of H2O and Al thermit was a good one.

[Edited on 14-12-2005 by Mr. Wizard]
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chemoleo
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[*] posted on 14-12-2005 at 10:56


Yes, it comes at around 120$ per gram, and purchases of more than a gram are highly restricted, due to its potential use as a chemical weapon. Laboratories normally use highly dilute solutions.
http://cns.miis.edu/pubs/week/040413.htm

Now, please, can we go back to somewhat more realistic options? Or are we going to discuss the use of plutonium oxide for thermites, for the next 10 posts?




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halogen
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biggrin.gif posted on 16-12-2005 at 03:22


Now that's an idea...

Wasn't an I2O5 mixture discussed earlier, or was it the roguesci thread?

[Edited on 16-12-2005 by halogen]




F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat with the evolution of chlorine.
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PHILOU Zrealone
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[*] posted on 16-12-2005 at 15:41


Quote:
Originally posted by Mr. Wizard

I think the 'thermit' reaction might take place under very high pressures, over the melting temperature of Al , as in an explosion. The analogy of H2O and Al thermit was a good one.

[Edited on 14-12-2005 by Mr. Wizard]


Again the only need for the reaction to occure is that the speed of reaction is superior to the heating and boiling of...as a mather of fact...there is a chance Al burns in a vapourised fluid...

I the example I gave Al powder /CCl4 is a detonable mix and CCl4 is volatile fluid...Maybe sore rare combination are even shok sensitive/flame sensitive...
In the case of OsO4 eveything depends on the capacity of OsO4 to give its oxygen and of the heat of reaction..Delta Gr and Delta Hr...

Quote:
Originally posted by halogen
Now that's an idea...

Wasn't an I2O5 mixture discussed earlier, or was it the roguesci thread?

[Edited on 16-12-2005 by halogen]


Despite the strong analogy between the type of reaction:
Oxygen transfer between an oxydiser and a reducing metal...
10 Al(s) + 3 I2O5(s) --> 5 Al2O3(s) + 3 I2(g)
It would no more be a thermite in the proper sense of the term...since I2O5 is a non metal oxyde...

So maybe start a new tread ;):P;) otherwise this will turn into a mess...were flash compositions will be mixed up with real thermites...:(




[Edited on 16-12-2005 by PHILOU Zrealone]




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[*] posted on 28-12-2005 at 00:49


I'm ready in the mood to try the CuO/Al in combination with the KMnO4 flash powder in some kind of confinded environment for a reactive target. This should be real fun on the firing range. Will take photo's and high quality video of the event. Stay tuned!
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[*] posted on 28-12-2005 at 18:05


Quote:
Originally posted by chemoleo
Now, please, can we go back to somewhat more realistic options? Or are we going to discuss the use of plutonium oxide for thermites, for the next 10 posts?


Considering the extreme reactivity and flammability of plutonium, I think it would potentially replace Al as the fuel. Pu is a very strong reducing agent....
That is also why plutonium oxide would make a poorer oxygen carrier in thermite.
For unrealistic thermites I would go with gold (III) oxide and Al.

How about peroxide compounds like zinc peroxide? Or maybe copper peroxide (dun't know how to make it) CuO2 which would be substantially more energetic than the CuO mixture.
I think the synthesis might be as simple as H2O2 + Cu(OH)2 -> CuO2 + 2H2O
But I am not sure (that method works to make zinc peroxide).

[Edited on 29-12-2005 by Chris The Great]
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[*] posted on 28-12-2005 at 21:17


...maybe Barium Peroxide/Magnesium --- Aluminum could be a substitue as well... thats a recepy for impact incendary 50 calibre bullets after they got rid of white phosphorus in WWII due to its instability. Just found out about that one...just sharing.
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neutrino
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[*] posted on 29-12-2005 at 09:45


Would this produce molten barium metal or just a bunch of oxide? If it is the latter, wouldn't this be more accurately classified as a flash powder than a thermite?
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[*] posted on 29-12-2005 at 14:36


Barium Peroxide /Al is certianly an incendary mixture...its not thermite thats for sure. The larger 150mm howitzer shells used a thermite filler with a percussion fuse and combustable core w/ small HE charge for dispersal.



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[*] posted on 31-12-2005 at 21:55


BaO<SUB>(2)</SUB> + Al > Al2O3 + Ba (unbalanced)

The caveat is the Ba has to be driven off by heat (yellow hot) and sublimated under vacuum. The reaction proceeds due to Al2O3's stability and Ba's (or any other alkaline earth, sans beryllium, for that matter) relatively low boiling point. Not exactly exothermic, though the peroxide will give some initial energy at least.

Ag2O2 would be pretty skookum.

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[*] posted on 1-1-2006 at 10:01


I'll see what else I can dig up on military tracer/incendary compositions. Heres another: KClO3/Mg/SrCl2 (red tracer)
KClO3/BaCl2/Mg (green chinese/Russian tracer)




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[*] posted on 19-1-2006 at 12:38


hellou,
i succesfully prepared chrome and silicium.
chrome is prepared out of Cr2O3 and Al, and silicium out of SiO2 and Al.

I started the reaction with some Mg-powder and a mixture out of KMnO4 and Glycerol..
there are some pics in a german chemnistry forum.if you want to see them,i can put them in....
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[*] posted on 8-2-2006 at 04:33


From NewScientist.com...



Exploding ink
A very unusual ink-jet printer cartridge, containing explosive ink, has been patented by Qinetiq, the commercial spin-off of the British Ministry of Defence.

The ink is a mixture of very fine aluminium particles, each 1 micrometre in diameter, particles of copper oxide 5 micrometres wide, epoxy varnish and alcohol. The ink is stable in liquid form, making it safe to print onto conventional paper, but forms an explosive fuse once dry.

An engineer can easily sketch out a printable fuse using computer imaging software, modifying the delay in milliseconds by changing the length, thickness and pattern of the line on the paper.

The ink can then be printed between a small strip of metal and a larger patch of explosive ink. Feeding a current through the metal strip makes it hot enough to ignite the fuse, which burns until it reaches the explosive patch. This explosion can then trigger the detonation of a much larger amount of explosives.

Qinetiq suggests printed fuses could be used for precisely controlling fireworks, triggering vehicle air bags or for conventional munitions. Ganging hundreds or thousands of fuses together could even make a miniature rocket engine capable of precisely adjusting the orbital position of a spacecraft, the company says.

Read the exploding ink patent in full here. http://tinyurl.com/d6sow




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[*] posted on 28-2-2006 at 05:49


That sounds very interesting. I'd like to try that.
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[*] posted on 28-2-2006 at 05:50


I don't see how you can DIY powder this fine.



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[*] posted on 28-2-2006 at 16:50


Crankyperson, I'd like to hear more details on your reaction with SiO2/Al.
I was never able to do it with this straight mixture, regardless the type of SiO2, even fine dried powder wouldnt do it. I did succeed with sulphur however.

How did you do it without?

Do post the link btw.




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[*] posted on 3-3-2006 at 11:17


I have used a blender to mill an alcoholic slurry of Al foil. The resulting dispersion of particle sizes were then sorted by various sedimentation and filtering techniques in the wet state. The finest fraction was collected in a filter and examined in an optical microscope and was found to mainly contain particles in the 1-5 micron range.
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[*] posted on 14-3-2006 at 06:18


Quote:
Originally posted by chemoleo
Crankyperson, I'd like to hear more details on your reaction with SiO2/Al.
I was never able to do it with this straight mixture, regardless the type of SiO2, even fine dried powder wouldnt do it. I did succeed with sulphur however.

How did you do it without?

Do post the link btw.


I once reacted ground quartz with magnesium dust in a test tube, On strong heating it started and the exothermic reaction was hot enough to deform my test tube.

One interesting side note is it makes a Silicon-magnesium complex that yeilds Silane gas (Bubbles flash when they hit air) if you dump the end product into HCl.

Not sure if aluminum would do the job...

[Edited on 14-3-2006 by Endo]
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biggrin.gif posted on 21-4-2006 at 16:42
Cu/Al BIG TARGET EXPLOSION VIDEO


yep, I'm back at it again. This time I tried to shoot a rather large exploding target using my .223 NATO - Ruger Mini-14. Enjoy the video... PS, it is in MP4 format.

[Edited on 22-4-2006 by kABOOM!]

Attachment: MVI_1431.MP4 (876kB)
This file has been downloaded 1636 times





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[*] posted on 21-4-2006 at 18:25


Nice.

Ballpark or exact weight of charge?

Tim




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