Aluminizing NG

[BrAiNFeVeR]

As I was discussing about manufacturing and detonating nitroglycerine, I brought up the idea about aluminizing NG to increase VoD and general performance by higher detonation temperature.

Since I am in the proces of dreaming up 20 ml trinitroglycerin, I feel inclined to do some tests. I was thinking first gelling it with a few % nitrocelluse, to better keep metal particles in their place, and then adding Al to get the right oxygen balance.

4C3H5(NO3)3 (l) --> 12CO2 (g) + 10H2O (g) + 6N2 (g) + O2 (g)

For every 4 molecules of NG that detonate, you get one O2.
So to succesfully oxidise the Al to Al2O3 you'd need: 12 NG + 2 Al-powder when ignoring the NC (which has a slightly negative OB iirc).

Al = 27
C3H5(NO3)3 = 12*3 + 5 + 3*14 + 9*16 = 137

(2*27)/(12*137) = 0.12 so 12% Al powder

In an idle attempt to try to improve OB while looking at the addition of NC, I rounded that 12 off to 10 (also for ease of working :p )

Okay; so why make a topic out of this ?
Basicly just to throw the idea out there and to hear some of the ideas you guys have about the right percentage of NC to make a runny NG gel. And to check my calculations ofcourse :p

[Mr Cool]

Remember that CO₂ and H₂O are capable of oxidising Al, so it might be fun to try it with even more:

H(CHONO₂)₃H + 6 Al --> 3 Al₂O₃ + 3 C + 2.5 H₂

Which would work out at 41.6% Al.

Metal contents that are higher still will produce thermobaric effects in confined spaces, even FAE effects if done right. Have you heard about those new stun grenades that use little Al FAE's? I think you could get it to work like that, but they'd be a lot less complicated than using BP to propell Al through little holes to produce the right F:A ratio. I think you could just add some Ti, Fe, Misch metal (lighter flint) etc grains or something to help with ignition.

You don't need much NC to thicken NG, try 5% maybe. It depends how thick you want it of course.

[Mr Cool]

Brainfever, M_rNG = 227, maybe when you calculated it you didn't press the "1" hard enough on your calculator when adding the mass of the oxygen, causing your value to be short by 90.
So for perfect OB to CO₂, H₂O and Al₂O₃:

100*(M_rAl*2) / ((M_rNG*6)+(M_rAl*2))
= 3.8% Al

[Microtek]

I think the greatest effect could be had by using enough Al to reduce the H2O to H2 and the CO2 to CO. That way the gas volume will be the same but the temp, and thus overpressure, will be higher.

[vulture]

Al will first reduce the CO₂ to C before reducing H₂O to H₂, because hydrogen has a greater affinity for oxygen than carbon.

EDIT: Unbelievable how many people forget the N₂ in their reaction equation, despite it's importance in gas production and energy output...

<small>[ March 06, 2003, 04:19 PM: Message edited by: vulture ]</small>

[Observer]

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<small>[ March 18, 2003, 08:07 PM: Message edited by: Observer ]</small>

[Guerilla]

Yeah, metals are mainly used to add more energy in underwater charges and rocket propellants (at least in the military means).

One kg of good quality aluminum can produce 32MJ of thermal energy. In contrast, the same amount of plain nitrocellulose gives 4MJ. Also, 1kg of aluminum (and 900 grams of oxygen that it needs to burn completely) takes almost the same volume as NC in itself. A proper NC/Al ratio can produce over 10 MJ/kg, so no wonder why metallisized explosives are so used. An efficiency can be sometimes doubled. :)

That was just an example with NC, I don't know how it'd go with NG. But I would appreciate if someone bothered to make some comparison between aluminized and non-aluminized NG or whatever.

[Mr Cool]

Oops, yes I did forget nitrogen Vulture, I was just thinking about the CO₂ and H₂O so I missed it. Luckily it wasn't important in what I was trying to say :) .

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">Only underwater explosives contain that large amounts of aluminium. Above water it will be counter productive if you are after blast effect.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">Read about thermobaric weapons. They are massively over-fueled to consume atmospheric oxygen, and to a lesser extent nitrogen, thus creating an under-pressure after the initial over-pressure when detonated in confined spaces. This causes the structure to experience more stress, and thus they can be more damaging than conventional HE when detonated inside. I suspect a compromise will be used between over-pressure from HE and under-pressure from Al/Mg.
Also the oxidation of aluminium by CO, CO₂ and H₂O are exothermic processes, as you have stated, so more energy will be released in total (for a given weight of HE).
That much Al will surely not be the most brisant mixture, but if you have enough to create the thermobarric effect in a confined space it might be beneficial depending on the application.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">But I would appreciate if someone bothered to make some comparison between aluminized and non-aluminized NG or whatever.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">You know what they say - if a job's worth doing, do it yourself!
I think it can be safely assumed that OB --&gt; H₂ and CO will be the best ratio as Microtek said - just as much gas, higher energy output, less dense detonation products...
Finding a better ratio would require a lot of carefully controlled, fairly large-scale testing which not many members have the ability to carry out.

[BrAiNFeVeR]

I knew my calculations needed checking, thanks for that Mr Cool.
But hey, at least I didn't forget my N2 :p

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> I would appreciate if someone bothered to make some comparison between aluminized and non-aluminized NG or whatever. </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">That was what I was thinking about doing.

I'll probably end up doing a series of small tests, but, lacking a good scale, I can't really measure per % increments ... which is why I'm aiming at kinda round figures.

Provided that most of the tests will be performed under a good layer of heavy mud, I don't think I have much room for any thermobaric effect, but maybe I'll try a small one at night, at a distant location.

Also, Simply Red suggested that it might become flame sensitive with the added Al, so this might make a good primary.

[Observer]

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<small>[ March 18, 2003, 08:07 PM: Message edited by: Observer ]</small>

[Mr Cool]

:rolleyes:
"Point source explosive"? It's only a point source if you have a small amount of it, 1000lb ceases to be a point source. There is no intrinsic property of this explosive that means it must be used in small amounts. And even small amounts in small confined spaces will produce the same effect. I don't know what you mean by a "volumetric" thermobaric explosive, please explain.
I'm not the only one who came to the conclusion that an underpressure is produced - military research labs did too.
Detonation of the HE produces a lot of very hot finely divided metal fuel in a confined space, and an overpressure. Said fuel very rapidly reacts with all oxygen and some nitrogen in the space, which will also cause heating and further expansion of the remaining gases. But at the same time solid metal oxides and nitrides are formed, taking up a tiny percentage of the space occupied by the gases which they contain. Therefore, pressure is reduced as the atmosphere in the confined space is consumed and the gases cool.
A cloud of Al powder will implode when ignited, after the initial expansion due to heating. It's common sense.

Also, newbies with 14 posts would do well not to imply that the moderators are idiots - </font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">And I don't see how you come to the conclusion that there will be under-pressure. It's like saying that a finely dived cloud of aluminium would implode when ignited.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">

[DBSP]

Just a small note here, Observer is xoo1246 = more than 500 posts.

[Observer]

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<small>[ March 18, 2003, 08:06 PM: Message edited by: Observer ]</small>

[Mr Cool]

No, it was me that got carried away, not you - if I'd known you'd been here a while I would have responded differently!
I thought you were a newbie, and it's always a good idea to let newbies know where they stand before they say something stupid and get banned. I didn't realise you were an established member who was already familiar with the way the Forum works.

Ah, I see what you mean about volumetric now, an FAE in effect. But either way, it's still gonna consume a quite large amount of gas in a short time. The 40% Al mixture won't because all the Al is oxidised by the NG, but here's an example using 30% NG (well, 29.6%), easily enough to get reliable detonations and disperse the Al well:

20 Al + H(CHONO₂)₃H --&gt; 3 Al₂O₃ + 1.5 N₂ + 2.5 H₂ + 3 C + 14 Al

14 Al + 10.5 O₂ --&gt; 7 Al₂O₃

Overall 156 litres of gas are consumed by just over 750g of mixture, in theory.
And if there is more Al after that, nitrogen will be consumed also, especially with Mg instead of Al. The rate of contraction will I'm sure be long compared to the time-scales involved with HE's, but not very long.

But the best bit is we'll get an energy output of almost 20MJ based on what Guerilla has said (I can't find my data book to check, but I trust his figures) from only 227g of actual explosive, 88kJg^-1 of HE or 27kJg^-1 of mixture :D . Lower power than the same amount of energy from pure HE, but still, it's considerable!

[BrAiNFeVeR]

SWIM finally got around to preparing the NG + NC + Al mixture :)

25-30 gram NG + 1.5 gram NC in acetone solution + 1.5 gram 400 mesh flake airfloat Al powder.

<img src="http://ci.cambridge.md.us/brainfever/NG5NC5Al-small.jpg">


SWIM will whip up some more plain NG to compare this mixture to.
Meanwhile, what would be a low cost way to compare the aluminized NG to the regular stuff ?

Detonations will be initiated by 0.1 gram AP with a speck of double salts on top of that.
SWIM hasn't found any compatibility errors between those 2 after 1 week storage at elevated temperature (40°C).

EDIT: What did I do to earn an avater?

EDIT2: Fixed picture (hopefully)
NBK, do you mean I'm staff now? :p
No really, I thought avaters where disabled for normal members ?

[nbk2000]

The link to your picture doesn't seem to be working.

Also, avatars are staff only.

[vulture]

That's odd. The picture clearly shows up in his post on my PC. Maybe your provider is blocking that IP block?

EDIT: Just saw Brainfevers edit, although the picture did show up when I checked this thread earlier. Damn what an unuseful post of me. You might aswell delete it. :(

[Kid Orgo]

Am I the only one that thinks the aluminized NG looks pretty?

mmm.... so shiny and explosive.

[nbk2000]

Ah, it's working now.

Yes, it does look very pretty.

But that didn't require a new post, now did it? "Post Whoring"...