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cutefix
May 21st, 2002, 02:40 AM
I had a intense discussion with an old colleague of mine about certain explosive formulation which by casual appearance does not seem workable, as it’s a known fact that wet ammonium nitrate does not detonate unless in certain special formulations such as what is available in tovex type explosives.
However he argued that these stuffs works according to his experience and he said these ideas was the origin of the water gel explosives as well as the Daisy Cutter.
It reputedly came from old patents assigned to Dow Chemical and Reynolds Metal .
As I do not have time to experimentally check this formulation,I will bring it here for your perusal and assesment ,as I find that most people here really like ammonium nitrate and aluminum explosives.

Aluminum Foil explosive:

Prepare 6 grams of cut-up commercial aluminum foil(0.0008 inch) into 0.25inch x 1 inch sizes.Place it into 120cc volume glass bottle.This will occupy a volume of about 100cc.Pour a 54 grams saturated solution of ammonium nitrate.Set it off with a 2 inch 50 grain detonating cord .A #8 blasting cap will set this stuff as well.

Aluminized Slurry.
Prepare a 150 gram charge containing the following proportion by weight.
42%aluminum(a mixture of equal parts by weight of 400 mesh powder and 100 mesh flake).
30%ammonium nitrate
28% water
Dissolve the ammonium nitrate in water then add the resulting solution to the aluminum powder/flake blend placed in an iron tube (whose other end is sealed) ,with stirring( 2 inch diameter and 4 inch long).Insert a strong blasting cap and detonate...

It was claimed that the blend of two types of aluminum particle sizes is the cause that will set this thing of easily and surely,than using just one grade of aluminum.
A variation of this is to add 0.5% gelatin or guar gum to prevent the aluminum from settling if the explosive is allowed to stand longer before using.This will stabilize the solution well from sedimentation of heavier particles.
It looks that the latter formula has similarity with the Daisy cutter formulation the only difference is the huge bomb uses polystyrene as suspending agent while the latter uses natural gums.
It was claimed that the experimentally determined rate of detonation of this second formulation was 4200 meters per second.

What do you think about these guys?

Microtek
May 21st, 2002, 04:12 AM
Well I can see the first one working, but the second one is really heavily overfuelled ( 4 times the fuel needed for balance assuming Al2O3 and H20 as products ). Of course if the aluminium oxide formation is favoured over water ( which I suppose it is ) then you'll get some free hydrogen which might create a prolonged overpressure from combustion with atmospheric oxygen. Anyway, I'm just speculating I haven't got any experience with slurries.

cutefix
May 22nd, 2002, 03:56 AM
Yeah,you are right Mikrotek.I did ponder on this matter also and arrived on similar conclusion .But ,I realized that the second reaction that produce hydrogen is more important in this case.
Indeed ,initially it does not look right, based on our current perception of explosives, in which ,the oxygen content should be higher (and never lower than the fuel) so as to produce desirable reaction and detonation products CO2,CO and H2O.
It is least expected that elemental hydrogen is released in this situation.However the presence of high amounts of metal in less oxygen environment available(in the composition), will allow this to happen ,without impairing the energy output but instead improving it.
And this unique formulation with higher metal content(overfueled ) was really applied in those 15,000 pounds daisy cutter dropped in Vietnam and Afghanistan.I was thinking then that it took quite a lot of booster to set it off, but that particular second formula(with higher aluminum content) was claimed by my former colleague that even a # 6 blasting cap can initiate it to high order detonation (which looks unbelievable).

That weapon maximized the performance of metals reaction with detonation products.
The detonation products carbon dioxide and water produces most of the heat of explosion.This leads to the possibility that a balanced aluminum-water mixture might itself be explosive under appropriate conditions.However its not detonable by any practical means,but I realized that several mixture of aluminum,ammonium nitrate and water are detonable but at higher critical diameters.Based on an actual field application, a 70 pound charge(composed of a slurry of aluminum,ammonium nitrate and water) placed on a 9 inch borehole released energy and formed a crater equivalent in performance to 110 pounds of pure TNT!

Looking at the simple reactions:
Normally aluminum will react with oxygen to form this
2Al + 3(O2)) --> 2Al2O3 (eq,1) which is requires enough oxygen,but it deficiency
will led to reduction.,not oxidation
Now in this particular case the detonation products CO2 and H2O will react with aluminum to produce this:
2Al + 3H2O --> Al2O3 + 3H2 (eq,2)
3CO2 + 4Al --> 3C + 2Al2O3 (eq 3)
Now if there are still unreacted Al and hydrogen will then interact with atmospheric oxygen,also resposible for the contribution of overpressure and extended explosion effect.
These equation(2& 3) gives off heats of reaction 1.76 kcal/g and 2.1 kcal gram respectively,which is much higher than normal explosives -TNT which gives only 1.090kcal/g .Other explosives like PETN can produce 1.490 kcal/gram and HMX can provide 1.480kcal/g(as based on Los Alamos explosive performance data -circa 1980).
therefore even if highly metallized explosives are overfuelled with metal; the metals unique interaction with detonation products have a positive effect on explosive performance.

I was hoping that somebody in these forum, who have the ingredients outright and keen interest in these phenomena, could check these claims and maybe confirm its potentials. These simple formulation(in particular, the second one) in improvised explosives; which can possibly give better performance compared with the favorites, dry ammonium nitrate based explosives- ANNM and ANNM/Al at an economical advantage.

Microtek
May 22nd, 2002, 05:10 AM
Yes I agree with your reasoning ( at least qualitatively; I haven't checked the calculations ), and it would be rather interesting to see if it works. Unfortunately, I'm restricted to using charges of less than five grams, which I'm sure would be too little. Nevertheless, lots of people must have the materials - Al foil, AN and water - to try the first one.

ALENGOSVIG1
May 25th, 2002, 07:51 PM
I have some info on an explosive composition that is a cross between both of the explosives in your post.

The explosive consists of:

Aluminum 32%
Ammonium Nitrate 20.4%
Calcium Nitrate 32.0%
Water 8.8%
Ethylene Glycol 6.8%

The aluminum is not powder, but aluminum foil. The foil is crumpled into small 1/8-1/4 inch balls. How you are supposed to crumple the foil into balls wasnt said. But i do know that cutting the foil into 1x1 inch pieces then grinding them in a coffee grinder for a few seconds will form nice little balls of foil.

It was said that the Exothermic reaction with aluminum forms aluminum oxide, hydrogen and probably methane

The explosive has a VoD of around 3300m/s @ 1.5 g/cc and is insensitive so it requires a booster.

Also, i tried the aluminum foil explosive you posted and it didnt detonate. 6 grams of aluminum foil was alot more than 100 ml. It was more like 250 when slightly pressed down. So as you can imagine, i had to press the foil down quite a bit to get it to be properly mixed with the AN solution. I used 1.5g of AP in the detonator.

<small>[ May 25, 2002, 06:55 PM: Message edited by: ALENGOSVIG1 ]</small>

nbk2000
May 26th, 2002, 04:45 AM
Perhaps the mix isn't so much as an explosive as a really fast burning incendiary.

A small amount of the AN explodes when the booster goes off, dispersing the rest of the mix. The heat of the explosion removes the water from the AN, which then reacts with the finely divided Aluminum fuel to burn at a very rapid rate. The excess fuel also burns up the oxygen from the surrounding air and water vapor, generating hydrogen which in turn burns.

Just my theory. :)

Anyways, the thermobarics use excess metal fuels to react with ambient oxygen from the air to increase blast/flame with no increase in weight, compared to conventional explosives.

Perhaps the reason for the foil, instead of powdered metal, is to delay the combustion of the metallic fuel till it can be dispersed sufficently through the air. This is also mentioned in thermobarics literature.

Microtek
May 26th, 2002, 07:34 AM
Now that you mention it, the AN/Al slurry is quite similar to the one used in the daisy-cutter we've been hearing so much about.

cutefix
May 26th, 2002, 11:55 PM
Thanks for your test Alen,...It looks that this combination will not detonate easily,however this keep me wondering why it did not detonate.If that explosive tests were derived from records of a reputable company as Dow chemicals,there is something wrong with the given procedure.There is a missing detail here...
I did ponder this out for a time and I can only reckon there were two causes of detonation failure.
First the character of ammonium nitrate solutions and second the detonation velocity of the cap.To my knowledge this slurries works best with PETN,tetryl,and RDX,pentolite booster and is not initiated with just primaries alone such as fulminate,azide and maybe even acetoneperoxide and HMTD.

Now,The most critical part ot this explosive is the ammonium nitrate solution.It is a common concept that this AN solution be made with water as this is the germ of the idea of this explosive,However AN can also form saturated solutions with other polar solvents such as liquid ammonia.
Liquid ammonia is capable of dissolving ionic salts(including AN) so its likely that the laboratory experiment done in Dow Chemical was made with alternative solvents such as liquid ammonia.Ammonia is reactive to metals including aluminum;therefore the explosive sensitivity will improve an in presence of shock this will help catalyze the detonation of AN solutions even in presence of large pieces of aluminum foil.
Hence this trial is favorable even with small scale experements (low critical diameters).But that theory is rather difficult to test at home laboratory.
As The handling liquid ammonia in makeshift labs is messy and because of its cryogenic character.There is a need also to seal the container with the finished explosive and to be set off electrically as ammonia gas liberated can be flammable and can form fuel -air explosive mixtures and therefore dangerous to set of by lighting a fuse connected to a blasting cap.
So if this is the case this particular first formula is unsuitable as “explosive toy” and is unsafe to use in improvised explosives.But its still interesting to think or to see if ammonia gas bubbled to a saturated solution of ammonium nitrate and then added to aluminum will work in this case.But I do not expect a succesful detonation in small size bombs with it as well.Just like with normal slurries it works best in large diameters( or bigger charges).

This liquid ammonia aluminum ammonium nitrate explosive is indeed an exception to the rule,and just another example of the potentials of these aluminized explosives.

AN /Al slurries are still reliable and useful explosives if formulated properly.

I am optimistic that the second formula is workable.It may even work using with just the 100 mesh aluminum flake as that is the most critical metal particle size needed in this explosive;however I do not expect the performance to be equal to the aluminum powder/flake blend...
Qoute:
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Anyways, the thermobarics use excess metal fuels to react with ambient oxygen from the air to increase blast/flame with no increase in weight, compared to conventional explosives.
-----------------------------------------------------------------------------------------------------

Indeed this is the basis for thermobaric explosives as well ;but that latest weapon used in Afghanistan is a dry based explosive -a PBX;unlike the Daisy cutter filler.
I was thinking that the formula has some similarity with the anti-aircraft explosives which are high blasts due to maximum amounts of reactive fine metal such as atomized aluminum.
A typical composition for this aerial explosive contain 54% very fine aluminum in combination with 10% composition B and oxidized with about 36% ammonium perchlorate
That was designed for low oxygen environment in upper atmosphere;but for lower altitude such as the latest thermobaric bombs set off at ground level(or lower); larger pieces of metal are desirable for best performance in these better oxygen content;thereby further enhancing the duration of the blast.

Alen that particular formula you describe above is workable ;and you are right ,its still needs a booster like PETN.to set it off reliably..

<small>[ May 26, 2002, 11:00 PM: Message edited by: cutefix ]</small>

Dr_Pind
November 27th, 2003, 07:54 AM
Speaking of the "Daisy Cutter", does anyone have the exact proportions used for the thermobaric filler or for other thermobaric AN/aluminium mixtures? Also, are any of these thermobaric compositions cap sensitive? I've found a source for pyro grade AL powder, and for this reason it could be interesting to try out the Daisy Cutter effect. The AN/ aluminium mix would also be rather cheap and very effective, since i have easy access to FGAN and AL powder.

One last thing. Is there a risk of the aluminium reacting with ammonium nitrate when wet? Boric acid should lower the risk, but i don't believe that it is used in the Daisy Cutter. Any ideas on how it is de-sentisized?

BrendanK
November 29th, 2003, 03:52 AM
Daisy Cutter...
Well, from my view I don't think that the water in the explosive mixture is to be reacted with Al... probably it may react. I think it's for the delay and to desensitise the mixture. The first explosion is to disperse the mixture into the air (spray) and the second explosion is to detonate the vaporized explosive in the air, the water here is to prevent the explosive from being detonated by the first explosion. Sorry... if I 'm wrong.

Axt
November 30th, 2003, 09:31 PM
Ive tried water/AN/Al mixes but all failed, though I could never get hold of guar gum to gell it (gelatin doesnt work in any usable percentages).

Nearly related, I also tried ANNM/foil made by painting a pasty mix of AN/NM/NC onto a sheet of foil and rolling into a stick, this was only done to give a bit of life to the ANNM detonations as they are rather bland. Didnt seem to help but, no flash or sparks.

I found a couple movies of these, download here (http://geocities.com/roguemovie3/), I think the first was the standard 2:1 AN:NM and the second was mostly NM with just enough AN to sensitise.

xyz
December 2nd, 2003, 04:05 AM
Cutefix, When you say liquid ammonia, do you mean ammonium hydroxide solution (as opposed to liquefied ammonia gas)?

IIRC, I am positive that I have seen the daisy cutter formula and ammonium hydroxide was in it.

tiac03
December 2nd, 2003, 06:54 PM
"The BLU-82/B (Big Blue 82) is a massive bomb containing 12,600lb (5715 kg) of DBA-22M, an aqueous mixture of ammonium nitrate, aluminum powder and polystyrene soap. "

"A Daisy Cutter contains 12,600 pounds (5,700 kg) of ammonium nitrate, aluminum and polystyrene, a combination known as GSX (gelled slurry explosives). GSX is commonly used in mining and is a commercial high explosive that is inexpensive and easy to produce."


Reading this I assume that packaging peanuts/styrofoam would do the trick for gelling the mix. (Just like the Napalm recipe)


"A fuel air munition basically puts out an aerosol fuel that then is ignited, burning the oxygen in the atmosphere, whereas a BLU-82 is basically just a big barrel of blasting slurry,"

That is the answer to BrendanK's post.


Lastly I want to ask whether or not some of the dissolved NH4NO3 will combine with the aluminum to form the Oxidizer Al NO3? (since i assume there must be an equilibrium in the mixture). Would this increase the oxidizer/fuel ratio?

Sorry if I am way off here, I never have been that great in chemistry. I'm more of the "Idiot's Guide To Chemisty" type. Mix this,and this, get this. Test product, count fingers, go home and make more. (If finger # < 20, seek help)


Al+NH4NO3+H2O <------> Al NO3 + NH4+ H20
or (Al + NH4NO3 + H2O <------> Al NO3 + (NH3+H3O)?)

On the right track or way off?

Bert
December 2nd, 2003, 11:23 PM
(If finger # < 20, seek help)

Um, if your family normaly has 20 fingers... How many grandparents do you normaly have?

xyz
December 3rd, 2003, 04:08 AM
Lol, I Think he meant fingers and toes...

tiac03
December 3rd, 2003, 12:56 PM
Yea my try at being funny just blew up in my face I guess... I was trying to imply that having an explosive go off too close to you can mess you up. (Concussion,Double vision) Therefore 20 fingers. (16 fingers and 4 thumbs)
"...I'm Retarded" -- (Chris Farley, Tommy Boy)

Desmikes
December 4th, 2003, 02:05 AM
I don't know how much different the reaction between gasous H2O2 would be with Al as opposed to H2O, but how about trying to replace that for H2O in a slurry? I'm thinking it would still liberate H and perhaps even more O. On the other hand I haven't tried mixing all 3 together, I hope H2O2 doesn't break down on contact with AN + AL. Any ideas?