megalomania
May 10th, 2003, 09:26 PM
CyclonitePyro
Frequent Poster
Posts: 55
From: You Wish
Registered: APR 2001
posted 04-10-2001 08:17 PM
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I've been playing with thermite and the thought entered my head, could I detonate ANFO with the incredible heat of thermite? I read stories of the Texas disaster thing in the 1950's where two ships carrying 1000's of tons of AN fertilizer detonated becuase of a fire in the cargo. I'm thinking that I could use an empty toilet paper roll as a mold and pack ANFO in and then make a hollow core in the middle to put thermite in. Would this detonate the ANFO?
FadeToBlackened
Frequent Poster
Posts: 201
From: Hell
Registered: MAR 2001
posted 04-10-2001 08:35 PM
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Although ive never done it i dont think ANFO would be very hard to detonate... Thermite might vaporize the FO for all i know. What would I do? Try it. Do not try anything I would do.. heh.
CragHack
Frequent Poster
Posts: 618
From:
Registered: DEC 2000
posted 04-10-2001 09:18 PM
--------------------------------------------------------------------------------
extreme heat will do a great job at detonating ANFO. NH4NO3 explosivley decomposes at a few hundred degrees celcius. the exact temp i am not sure. the heat has to be pretty intense though (that is why it is suggested you dry you AN in the oven, lots of heat but not enough to set it off)
------------------
...Æ
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 04-10-2001 09:23 PM
--------------------------------------------------------------------------------
I've been wondering about exactly the same thing, since AN will definitely "go off" with prolonged high heat. As you rightly point out, the Texas City disaster was one such instance. However, I dont know if this reaction is true detonation or simply a very "high order" deflagration. While deflagration can result in detonation, I also don't know if the deflagration/detonation transition (DDT) would occur with small quantities or whether a certain mass is required.
A paper examining HEVR (high explosive violent reaction) phenomena addresses heating reactions and claims that true detonation did not occur with the military explosives tested. However, AN-based explosives were not considered. It's an interesting read and provides a good overview of the issues involved. Go here and select the pdf file:
http://www.osti.gov/bridge/product.biblio.jsp?osti_id=329510
I think thermite is probably out - because of its rapid burn rate it would probably only affect a small percentage of the total AN mass. Apparently heating must be sustained over a period sufficient to heat the entire mass for anything approaching detonation of the whole to occur. This was certainly the case at Texas City, but how might this effect be achieved on a smaller scale? I'd like to know the answer to this myself.
SMAG 12B/E5
Frequent Poster
Posts: 61
From:
Registered: FEB 2001
posted 04-10-2001 11:32 PM
--------------------------------------------------------------------------------
I once partially filled an ammonia tank, approx 6" X 18", with a mixture of ammonium nitrate, powdered charcoal and sulfur, fused a 1/2 inch opening at one end and placed the unit on the bank of a pond. I ignited the fuse and my wife and I backed our truck away to a safe distance. Upon ignition, the device spewed gasses louder until it became airborne. It flew about 10 feet and detonated in midair. We found one piece of the tank. The metal distortion indicated high order detonation. The combination of heat and pressure caused a transition from deflagation to detonation. Iron powder and/or copper powder might decrease the transition time.
simply RED
Frequent Poster
Posts: 240
From: HELL
Registered: OCT 2000
posted 04-11-2001 04:20 AM
--------------------------------------------------------------------------------
Very fine alluminium powder mixed with the ammonium nitrate makes a mixture that burns hellish fast if ignited in open air (80%AN : 20% AL) (the alluminium could be more). I think that if you put this in a pipe and ignite with thermite, the transition between deflagration to detonation will be very fast. Also a mixture of AN containinig NH4Cl is reported to transmit from deflagration to detonation easily("IMPROVISED MUNNITIONS from ammonium nitrate"). But this transition needs a metal container to work with small quantities. Toilet rollpaper will not work.
I also think that detonating ammonium nitrate that way is only for knowledge and experimenting purposes, It's much easier to make a detonator !
Mr Explosi
New Member
Posts: 26
From: Germany
Registered: MAR 2001
posted 04-11-2001 01:20 PM
--------------------------------------------------------------------------------
Sorry, but it is never possible to detonate ANFO with thermit!! Becaus you musst bring the ANFO in a 1/1000 sek. over 1000° C !
So only a ini explosive can do it!
jin
Frequent Poster
Posts: 111
From: uk
Registered: SEP 2000
posted 04-11-2001 02:30 PM
--------------------------------------------------------------------------------
i read somewhere you could get anfo in a pipe bomb to deflagrate with thermite used to ignite the anfo, and cause the pipe to expolde.
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-11-2001 02:49 PM
--------------------------------------------------------------------------------
It is possible for AN to detonate by fire but it has to be in bulk - hundreds of tonnes. If the AN is molten and the pressure spikes above (I think) 200psi the detonation can occur. Obviously this build up of pressure can only occur when the AN is in mass amounts.
Heating AN in an air-tight steel pipe might cause detonation. But I'm afraid it isn't as easy as just putting thermite on ANFO.
CyclonitePyro
Frequent Poster
Posts: 55
From: You Wish
Registered: APR 2001
posted 04-11-2001 03:05 PM
--------------------------------------------------------------------------------
Thanks for all the info. Would it be possible to use slow burning thermite to heat the ANFO an then have a charge of flash powder go off to get a pressure spike of way more than 200psi, wouldn't that detonate the ANFO?
jin
Frequent Poster
Posts: 111
From: uk
Registered: SEP 2000
posted 04-11-2001 03:31 PM
--------------------------------------------------------------------------------
you cant get anfo to detonate without a detonator.you can get it to deflagrate(burn)under heavy confinement like a pipebomb and cause the pipe to expolde.you could try useing thermite or flashpowder to ignite the anfo when its under the confinement.
Mr Explosi
New Member
Posts: 26
From: Germany
Registered: MAR 2001
posted 04-11-2001 03:49 PM
--------------------------------------------------------------------------------
Use ANNM! That is the best way! If you didn t have some ANNM use a few hundred gram of a Peroxid, but that is too dangerous!
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-11-2001 07:05 PM
--------------------------------------------------------------------------------
Remember that ship'o'AN that detonated? When it was burning they contacted an explosives expert to ask if there was a risk of detonation. He said "it can't detonate without a detonator"
The best way to find out whether AN can detonate in a sealed pipe would be to try it and see. The AN would need to be molten, I'm not sure whether the thermite charge would reliable melt all the AN or intime for the flash charge. What I would do is simply flow the pipe in a fire, the AN would melt, then start to decompose into gas which would pressurise the pipe.
jin
Frequent Poster
Posts: 111
From: uk
Registered: SEP 2000
posted 04-11-2001 09:46 PM
--------------------------------------------------------------------------------
i thought anfo expolsives turned to gas from soild without turning moltern i think if the temperature is correct called sublimation like the temperature from flash or thermite.
CyclonitePyro
Frequent Poster
Posts: 55
From: You Wish
Registered: APR 2001
posted 04-12-2001 10:53 AM
--------------------------------------------------------------------------------
I wanted to see if I could detonate ANFO with thermite because I didn't want to make AP or HMTD, but I figured what the hell, if I make AP, I can set off ANFO or ANNM, and have the AP to use alone. I don't want to have to use metal pipes to heat AN or any of that, much simpler to make a AP detonator. Thanks
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-12-2001 02:09 PM
--------------------------------------------------------------------------------
Yeah, probably would be a lot easier to just use a detonator
Frequent Poster
Posts: 55
From: You Wish
Registered: APR 2001
posted 04-10-2001 08:17 PM
--------------------------------------------------------------------------------
I've been playing with thermite and the thought entered my head, could I detonate ANFO with the incredible heat of thermite? I read stories of the Texas disaster thing in the 1950's where two ships carrying 1000's of tons of AN fertilizer detonated becuase of a fire in the cargo. I'm thinking that I could use an empty toilet paper roll as a mold and pack ANFO in and then make a hollow core in the middle to put thermite in. Would this detonate the ANFO?
FadeToBlackened
Frequent Poster
Posts: 201
From: Hell
Registered: MAR 2001
posted 04-10-2001 08:35 PM
--------------------------------------------------------------------------------
Although ive never done it i dont think ANFO would be very hard to detonate... Thermite might vaporize the FO for all i know. What would I do? Try it. Do not try anything I would do.. heh.
CragHack
Frequent Poster
Posts: 618
From:
Registered: DEC 2000
posted 04-10-2001 09:18 PM
--------------------------------------------------------------------------------
extreme heat will do a great job at detonating ANFO. NH4NO3 explosivley decomposes at a few hundred degrees celcius. the exact temp i am not sure. the heat has to be pretty intense though (that is why it is suggested you dry you AN in the oven, lots of heat but not enough to set it off)
------------------
...Æ
c0deblue
Frequent Poster
Posts: 229
From:
Registered: JAN 2001
posted 04-10-2001 09:23 PM
--------------------------------------------------------------------------------
I've been wondering about exactly the same thing, since AN will definitely "go off" with prolonged high heat. As you rightly point out, the Texas City disaster was one such instance. However, I dont know if this reaction is true detonation or simply a very "high order" deflagration. While deflagration can result in detonation, I also don't know if the deflagration/detonation transition (DDT) would occur with small quantities or whether a certain mass is required.
A paper examining HEVR (high explosive violent reaction) phenomena addresses heating reactions and claims that true detonation did not occur with the military explosives tested. However, AN-based explosives were not considered. It's an interesting read and provides a good overview of the issues involved. Go here and select the pdf file:
http://www.osti.gov/bridge/product.biblio.jsp?osti_id=329510
I think thermite is probably out - because of its rapid burn rate it would probably only affect a small percentage of the total AN mass. Apparently heating must be sustained over a period sufficient to heat the entire mass for anything approaching detonation of the whole to occur. This was certainly the case at Texas City, but how might this effect be achieved on a smaller scale? I'd like to know the answer to this myself.
SMAG 12B/E5
Frequent Poster
Posts: 61
From:
Registered: FEB 2001
posted 04-10-2001 11:32 PM
--------------------------------------------------------------------------------
I once partially filled an ammonia tank, approx 6" X 18", with a mixture of ammonium nitrate, powdered charcoal and sulfur, fused a 1/2 inch opening at one end and placed the unit on the bank of a pond. I ignited the fuse and my wife and I backed our truck away to a safe distance. Upon ignition, the device spewed gasses louder until it became airborne. It flew about 10 feet and detonated in midair. We found one piece of the tank. The metal distortion indicated high order detonation. The combination of heat and pressure caused a transition from deflagation to detonation. Iron powder and/or copper powder might decrease the transition time.
simply RED
Frequent Poster
Posts: 240
From: HELL
Registered: OCT 2000
posted 04-11-2001 04:20 AM
--------------------------------------------------------------------------------
Very fine alluminium powder mixed with the ammonium nitrate makes a mixture that burns hellish fast if ignited in open air (80%AN : 20% AL) (the alluminium could be more). I think that if you put this in a pipe and ignite with thermite, the transition between deflagration to detonation will be very fast. Also a mixture of AN containinig NH4Cl is reported to transmit from deflagration to detonation easily("IMPROVISED MUNNITIONS from ammonium nitrate"). But this transition needs a metal container to work with small quantities. Toilet rollpaper will not work.
I also think that detonating ammonium nitrate that way is only for knowledge and experimenting purposes, It's much easier to make a detonator !
Mr Explosi
New Member
Posts: 26
From: Germany
Registered: MAR 2001
posted 04-11-2001 01:20 PM
--------------------------------------------------------------------------------
Sorry, but it is never possible to detonate ANFO with thermit!! Becaus you musst bring the ANFO in a 1/1000 sek. over 1000° C !
So only a ini explosive can do it!
jin
Frequent Poster
Posts: 111
From: uk
Registered: SEP 2000
posted 04-11-2001 02:30 PM
--------------------------------------------------------------------------------
i read somewhere you could get anfo in a pipe bomb to deflagrate with thermite used to ignite the anfo, and cause the pipe to expolde.
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-11-2001 02:49 PM
--------------------------------------------------------------------------------
It is possible for AN to detonate by fire but it has to be in bulk - hundreds of tonnes. If the AN is molten and the pressure spikes above (I think) 200psi the detonation can occur. Obviously this build up of pressure can only occur when the AN is in mass amounts.
Heating AN in an air-tight steel pipe might cause detonation. But I'm afraid it isn't as easy as just putting thermite on ANFO.
CyclonitePyro
Frequent Poster
Posts: 55
From: You Wish
Registered: APR 2001
posted 04-11-2001 03:05 PM
--------------------------------------------------------------------------------
Thanks for all the info. Would it be possible to use slow burning thermite to heat the ANFO an then have a charge of flash powder go off to get a pressure spike of way more than 200psi, wouldn't that detonate the ANFO?
jin
Frequent Poster
Posts: 111
From: uk
Registered: SEP 2000
posted 04-11-2001 03:31 PM
--------------------------------------------------------------------------------
you cant get anfo to detonate without a detonator.you can get it to deflagrate(burn)under heavy confinement like a pipebomb and cause the pipe to expolde.you could try useing thermite or flashpowder to ignite the anfo when its under the confinement.
Mr Explosi
New Member
Posts: 26
From: Germany
Registered: MAR 2001
posted 04-11-2001 03:49 PM
--------------------------------------------------------------------------------
Use ANNM! That is the best way! If you didn t have some ANNM use a few hundred gram of a Peroxid, but that is too dangerous!
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-11-2001 07:05 PM
--------------------------------------------------------------------------------
Remember that ship'o'AN that detonated? When it was burning they contacted an explosives expert to ask if there was a risk of detonation. He said "it can't detonate without a detonator"
The best way to find out whether AN can detonate in a sealed pipe would be to try it and see. The AN would need to be molten, I'm not sure whether the thermite charge would reliable melt all the AN or intime for the flash charge. What I would do is simply flow the pipe in a fire, the AN would melt, then start to decompose into gas which would pressurise the pipe.
jin
Frequent Poster
Posts: 111
From: uk
Registered: SEP 2000
posted 04-11-2001 09:46 PM
--------------------------------------------------------------------------------
i thought anfo expolsives turned to gas from soild without turning moltern i think if the temperature is correct called sublimation like the temperature from flash or thermite.
CyclonitePyro
Frequent Poster
Posts: 55
From: You Wish
Registered: APR 2001
posted 04-12-2001 10:53 AM
--------------------------------------------------------------------------------
I wanted to see if I could detonate ANFO with thermite because I didn't want to make AP or HMTD, but I figured what the hell, if I make AP, I can set off ANFO or ANNM, and have the AP to use alone. I don't want to have to use metal pipes to heat AN or any of that, much simpler to make a AP detonator. Thanks
Anthony
Moderator
Posts: 2306
From: England
Registered: SEP 2000
posted 04-12-2001 02:09 PM
--------------------------------------------------------------------------------
Yeah, probably would be a lot easier to just use a detonator