Sciencemadness Discussion Board

Fuel-Air Explosives

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mfilip62 - 10-2-2007 at 12:20

Hy folks,
Recently I was trying to create an fireball with
an 1 dl of gas and 100-200g of dinamite!

There was no fireball butt presure,destruction and noise was unproportionall with the amount of explosive!
Washing machine,my victim,litteraly disapeard!

I DO NOT know if i accidentally make a Fuel-Air Explosive
butt please checked this video,and please answer my on some questiones!

http://www.youtube.com/watch?v=j9xCgNdZPKk

1.)How long is delay between those 2 detonations!
(starting det. and "detonating" det.)

2.)Exacly which fuel does he used!(benzine,ether...or?)

3.)I think that both explosives must be with very
positive OB,an second one must make greater heat or flame!
Cann I use open fire burner instead of second explosive!?!?!?

Please help me someone!
That looks like a lot of fun!

P.S.;Sorry for my bad english!

nitro-genes - 10-2-2007 at 13:11

Your third question clearly indicates that you don't have a clue about the principles behind a FAE. The timing between the two charges is very critical and can probably only be reliably done with EBW firing + additional electronics for the timeinterval. The timeinterval between the two detonations further depends on the size of the charge and the fuel used and moreover are there only a subset of difficult obtainable fuels that will work reliably...

How interesting FAE's may be, it remains to be seen if a further discussion will be allowed anyway, especially seen your other posts...

[Edited on 10-2-2007 by nitro-genes]

mfilip62 - 11-2-2007 at 09:22

I understand that,butt why cant I just simply use open flame!!!

Try to mesaure time betwen two detonations(Aurora program...),and it seems to be around 20ms!
I think that this is definitly 20ms becouse there are electric detonators with delay of 20ms to buy,I have 3 of those det.!

Looks like you didnt understand the question!!!
I was asking for that explosion on the video clip precisely,not generally!!!

And I dont see what is wrong with mine 3. question!
Logically,if FAE has wery negativ OB and it uses oxygen from the air to burst,I think that first one,"spreading" explosive may bee
some with OB!
You understand,so that fuel uses that oxigen as well as atmospheric,becouse,if firs explosive has negative OB,there is no oxygen for aerosol fuel!
Do You understand!?

And does anyone know which one mixure is fuel!?

Thanks

mfilip62 - 11-2-2007 at 09:32

Oh yes,and there is no need for some special electronic like EBW firing you can just use two detonators,(one instant and one with delay)
wierd them parallel,and make contact with 9V dry cell battery!

Belive me,maybe you cann find in some blasters manuals not to use baterryes,butt that worth yust for large amount of caps(5+),
I am doung so for many years and it NEVER misfire!

YT2095 - 11-2-2007 at 11:45

for a start Why use "dinamite"? AND why so much?

if you want a One-Pot type use something like BP and bag of fuel in a pot, BP underneath.
if you want to use Gas then use a thin can gas container and put the charge on the top of it, YES ON THE TOP!
not under it. you`ll need something a little more pokey than BP though, Flash powder charges are good, be sure to add some coarser grain material in the mix as this will stay hot enough for longer.

and be SURE to do this well away from people or property and give yourself More than enough time to get away safely.

nitro-genes - 11-2-2007 at 12:44

Quote:
Originally posted by mfilip62
I understand that,butt why cant I just simply use open flame!!!


Because the fuel/air cloud doesn't behave as a sensitive primary explosive so can't make DDT upon ignition by flame. For example, TNT will burn nice and quietly when molten and exposed to flame though it will never detonate. The fuel cloud behaves similary insensitive and it's sensitivity will quickly drop even further when the mixture is too rich in fuel (too early) or too rich in air (too late). The reason is that the atmosphere only contains 21% oxygen, if it were composed of 100% oxygen things would have been much easier! The large amount of inert N2 absorps a lot of the heat liberated from the detonation, making it very insensitive. Furthermore, the fuel is dispersed as a fine mist, but still, these droplets have a very large size compared to the intramolecular distances between fuel and oxidizer like that in regular HE's.Some fuels allow a larger time frame than others, but in general the sensitivity of mixtures with gasoline are so insensitive that they will not detonate reliably even in a EBW fired professional setup, this is why they use other fuels or oxidizer additives to complement the fuel. ...

This was the third question I was refering to btw, I mean why would they use two charges with precisely determined delays if some romantic candle light would have done the same? :P
Quote:
Originally posted by mfilip62Try to mesaure time betwen two detonations(Aurora program...),and it seems to be around 20ms!


Amazing what people can accomplish if you stimulate them a bit! :D
Quote:
Originally posted by mfilip62You understand,so that fuel uses that oxigen as well as atmospheric,becouse,if firs explosive has negative OB,there is no oxygen for aerosol fuel!


Hehe, even in very oxygen balanced explosives like ETN or NG, how much oxygen will avialable on a weight basis? Remember that the fuel outweighs the explosive 100 times and would need a further 4-5 times that weight of oxygen in order to combust all the fuel completely! So the oxygen balance of the explosive is really not important...
Quote:
Originally posted by mfilip62Oh yes,and there is no need for some special electronic like EBW firing you can just use two detonators,(one instant and one with delay)
wierd them parallel,and make contact with 9V dry cell battery!


Yes, I use electric firing on occasion as well. :) A simple ignitor may look like it fires imidiately, though on a ms scale I'm quite sure two ignitors may be worlds apart! Ever used an slightly more empty battery? You will see that this difference becomes even larger, some fire after seconds, others far under a second. The more juice you pump into the ignitor, the faster and more reliably it will respond, with EBW firing beeing the upper limit...

I wouldn't mind you proving me wrong though! :D

[Edited on 11-2-2007 by nitro-genes]

DeAdFX - 11-2-2007 at 20:50

I recommend you use Epoxy ethane[AKA ethylene oxide] C2H4O or the propylene variant. This fuel should be much easier to ignite than gasoline. However it is a hell of a lot more toxic and if you aren't able to get the epoxy ethane to detonate then you will have a large toxic cloud of death.

Anywho a fireball and a fae are two different things.

mfilip62 - 12-2-2007 at 11:34

Quote:
Originally posted by nitro-genes

Yes, I use electric firing on occasion as well. :) A simple ignitor may look like it fires imidiately, though on a ms scale I'm quite sure two ignitors may be worlds apart! Ever used an slightly more empty battery? You will see that this difference becomes even larger, some fire after seconds, others far under a second. The more juice you pump into the ignitor, the faster and more reliably it will respond, with EBW firing beeing the upper limit...

I wouldn't mind you proving me wrong though! :D

[Edited on 11-2-2007 by nitro-genes]


I done a bit research on that!
Those comercial detonatorsa are wery wery sensitive,
and eawen the slightles curent will detonate them instantly!
However,mine homemade detonators have some delay,and I often linked one instant and one homemade to make delay betwen 2 detonations!
And the best thing is to conect 2 9V baterryes together serially(stick them together with the duch tape,and conect one + with one -,and you will see how strong it becames!)

O.K. I must explain you spmething about comercial detonators,if you have 2 or more detonators conected paralel
some of them have dellay and some of them do not!
Now when you pass curent trught them they WILL all be ignited at the same moment,those instant and those with dellay,butt those instant will explode instantly,and those with dellay will have their retardators ignited and will explode afther some time!Understand me!
Cousin of mine was working in explosive factory,soo you hardlly can beat that!(Yust jocking:P)

nitro-genes - 12-2-2007 at 13:10

Quote:
Originally posted by mfilip62
Cousin of mine was working in explosive factory,soo you hardlly can beat that!


I've been cleaning floors in a bread factory as a student, still know shit about baking bread though... :D (just kidding)

I didn't know you were talking about commercial delay detonators btw, they would be far more reliable than any homemade ones I guess. Still it wouldn't be an easy job, be sure to capture it on video if you make any attempts!

For fuels you would like a broad mixture range with air in which the fuel cloud is still able to detonate.

-->http://en.wikipedia.org/wiki/Explosive_limit

Propylene oxide(l) is about 2-36% and ethylene oxide(g) is 3-100%, probably due to explosive polymerization, just like vinyl compounds can do. In practise they use a mixture of both because ethylene oxide alone also polymerizes on storage and has an extremely high vapour pressure due to is low boiling point (10 deg C). The mixture is probably a trade off between detonability and energy since ethylene oxide is partly oxidized having an oxygen attached, so proplene oxide would release more energy on a weight basis than ethylene oxide. Looking at l.e.l. and u.e.l. it turns out that there are only a few fuels that are usable, with diethyl ether beeing the best option considering explosive limits (equals propylene oxide) and energy release, although obtaining a few liters for an experiment would be both costly and difficult. Methanol has the same explosive limits in air as ether does, though would release substantial less energy on a weight basis due to the carbon beeing already partly oxidized. Ethanol would possibly be the only real OTC options for an FAE with one fuel compound, though this is rarely found without any water. Water having an extremely large specific heat would take up a lot of heat from the detonation, making the fuel cloud possibly much less sensitive then with anhydrous ethanol...

I've also read about additives like butyl nitrite and propyl nitrate beeing added to regular gasoline too make them usefull as a fuel, though it needed high percentages of them (10-20%) which would make things much more costly and laborous. Methanol or ethanol with 5-10% of nitromethane could work as well as a simple and easily made mixture. A real easy additive to sensitise hydrocarbon fuels would be nitric acid, though most of the fuels are either incompatible with that or do not dissolve. Some perchlorate and nitrate salts would make nice additives as well, as I know for sure that at least some of them can dissolve pretty good in ethanol or methanol...

[Edited on 13-2-2007 by nitro-genes]

mfilip62 - 13-2-2007 at 09:29

You theory sounds perfect butt it is still a teory!!!!
I understand that you want to help, butt posting souch theoretic science factscan only led us to confusion!
Firstly leave or ignore chemicals like ethylene oxide,Propylene oxide,extremly sensitive,poisonous and expensive materials alone becouse we mortals will never be able to eaven see one fo those! RIGHT!?
For example i never saw nitromethane or concetrated nitric acid in my life butt I still use a lott of explosives!
There is nowhere to buy NM in my country,and you cann only steal 30+ years old nitric acid in the school!

Butt you cann pretty easily make anhydrous ethanol!
Yust buy 94-96% ethanol or wery wery strong fire water we call
"prvina"(that is redestiled greape fire wather:D)
and putt some chunk of Calcium Oxyde(CaO) in it!
And that is that!

If you find some FAE mixtures with rates plase post them!

P.S:How do you make your homemade electric detonators!

[Edited on 13-2-2007 by mfilip62]

Zinc - 13-2-2007 at 11:38

Quote:
Originally posted by nitro-genes
Propylene oxide(l) is about 2-36% and ethylene oxide(g) is 3-100%, probably due to explosive polymerization, just like vinyl compounds can do.


Can then ethylene oxide be detonated in the liquid form (it would not really detonate but undergo an explosive polimerization)?

nitro-genes - 13-2-2007 at 16:16

Quote:
Originally posted by mfilip62
You theory sounds perfect butt it is still a teory!!!!
I understand that you want to help, butt posting souch theoretic science factscan only led us to confusion!
Firstly leave or ignore chemicals like ethylene oxide,Propylene oxide,extremly sensitive,poisonous and expensive materials alone becouse we mortals will never be able to eaven see one fo those! RIGHT!?
For example i never saw nitromethane or concetrated nitric acid in my life butt I still use a lott of explosives!
There is nowhere to buy NM in my country,and you cann only steal 30+ years old nitric acid in the school!


Maybe you can steal a couple of liters of ethylene or propylene oxide from your junior highschool, I'm sure they will have it stocked up by the gallons for FAE demonstrations to pupils and for making mustard gas...

I merely tried to give my thoughts about the possible fuels usable for FAE in the hope to get some meaningfull opinions of others and start a discussion about it on this discussionboard. If this is all too much for you, I'll stop discussing it and you can start experimenting with them right away without thinking about concequences, availability or possible flaws of your method...:P

Microtek - 14-2-2007 at 01:38

How about acetylene ? It has a very broad span from LEL to UEL, large energy content and is very brisant even if just ignited by flame. Acetylene tanks ( so dissolved in acetone under pressure ) have been used in terrorist attacks in the past although on a quite large scale.
I have been toying with the idea that maybe a brisant HE could be used to pulverize a block of CaC2 and mix it with water to release a cloud of acetylene, which would then be detonated. The time delay would need to be longer, and maybe it wouldn't work at all ( maybe the CaC2 isn't reduced to sufficiently fine dust ), but only a series of experiments will tell.
I won't be making the experiment myself due to the necessarily large scale, but if someone else could I would like to hear about it.

mfilip62 - 14-2-2007 at 07:25

Yeah,acetilene looks like good idea!
I have better one,butt it will be too expensive,too powerfool and will probably brought police to you door!

When You use Oxygen/acetilene burner optimal spending
ratio is around 2 bottles of acetilene(etin) per one bottle of oxygen!
So You buy 2 bottles of etine and 1 bottle of oxygen,put some plastic explosive betwen them and viola!!!
You probably dont even need second charge to acomplish full detonation!

Second idea is that you try with H2O!
Do the same thing with bottles of oxygen and hydrogen or to electrolyse H2O,
then,compress H2 and O2 in to the one bottle
with compressor,and then detonate that bottle!
Butt I probably think that compresing H2 and O2 together
is wery wery dangerous!

nitro-genes - 14-2-2007 at 07:38

Quote:
Originally posted by Zinc
Can then ethylene oxide be detonated in the liquid form (it would not really detonate but undergo an explosive polimerization)?


Polymerization reactions can be exothermic and fast enough to self ignite, it needs catalyst or so to become really violent though it will never resemble a real detonation. The epoxide bonds are very stressed, just like the short and electron crowded tripple bond of acetylene or the bonds from small cyclic alkanes like cylcopropane or butane. These bonds need less energy to be broken and can release a lot more energy when they form more stable bonds with oxygen or even another molecule like itself. That is why these fuels can violently polymerize and can detonate in higher concentrations in the air...

I thought about the calciumcarbide/water mixture as well. since acetylene is a gas and can make DDT in very small amounts with oxygen, the resulting gascloud probably wouldn't even need a second charge to detonate at all, like is needed for aerosolic fuels. One brisant charge to both pulverize the calciumcarbide and ignite the gascloud by adding some coarse aluminium powder would have the advantage that the delay provided by the calcium carbide to react with the water may provide a mixture with air that is able to make DDT. One of the downsides is that the reaction of calciumcarbide with water yields only a 25 weight percentage of acetylene as the other 75% is made up by the formed calcium hydroxide, what makes the energy yield from a weight perspective about as efficient as conventional explosives...

[Edited on 14-2-2007 by nitro-genes]

nitro-genes - 14-2-2007 at 08:16

Quote:
Originally posted by mfilip62
Yeah,acetilene looks like good idea!
I have better one,butt it will be too expensive,too powerfool and will probably brought police to you door!


Surely someone that has made enough ANFO to blow up a car will not worry about the police in front of his door over some gas explosion. Which have absolutely nothing to do with fuel/air explosions btw...

The more powerfool the better eh? :D

[Edited on 14-2-2007 by nitro-genes]

Microtek - 14-2-2007 at 10:19

When I looked over the numbers some time ago ( on the HE/carbide/water system ), I found like you did that it would be about as energetic on a weight basis as regular HEs. However, if it worked as envisioned, it would be a quite cheap method for generating large explosions if a high brisance wasn't needed.

mfilip62 - 14-2-2007 at 10:32

I agree with you nitro-genes butt when you buy
presurized gas here you actually just rent gas container!
If you destroy it or blow it up....you have wery long procedure to go trought,first you must have some personal ID to rent it,if you want to buy etine,you must have in writing proof that you are able to handle with that kind of material,(and allmoust for every kind of gas!),report the status of container
every 3-6 months(depending on the tipe of gas) to the company,and if you "lost" it, they report that to the police...
and then starts real problems!!!
You must know that lawsuits here endure for ages,
bureaucracy is insane,and coruption...
I dont want that kind of charade,that is for sure...

I know what I am talking about!!!!

It is probably becouse Al-Queda attack killing few persons
and destoying police station 1994.!
(Stupid moslems from Bosnia!)

Only potential hazardous chemical that is not restricted is KAN,
(AN/CaCO3/MgCO3)chamical fertilizer,and H2O2 which is semi restricted!

It is paradoxically that mine country is full of explosives left after war,and some stupid idiot put ban on chemicals!
(Butt you must agree that a lot of explosiwes left is not such bad thing:D)

Belive me that explosion of C2H2/O2 mixture is anything butt
ordinary gas explosion!I saw it once!
It actually erase EWERITHING on it way!

hinz - 14-2-2007 at 10:42

Does the carbide react fast enough with the water to build up a acetylene clowd? The carbide must be grind very well for this, but if you grind carbide in a ball mill, you have to use dry air in your container, if not the carbide dust will react with H2O. Maybe a better idea would be to solidify acetylene in a LN2 cold trap and place this acetylene "snow" around the booster charge. As it explodes, it will be finely distributed and the acetylene will take up the heat of the sourounding air and vaporise. This will happen much faster than the reaction between carbide and water, for this, the water and carbide need to be well mixed in the few milliseconds of explosion. If someone tries it with carbide, a good option would be to leave away the water around the chare and try it at a rainy day.

nitro-genes - 14-2-2007 at 12:03

Lol, just for fun calculated the optimum humidity of water vapour in the air to be stoichiometric with the amount of oxygen for the formed acetylene to combust with. Though even with a relative humidity of 100% at 20 deg. C. (20 grams of water per m3 of air) there is still a 7 fold excess of oxygen compared to the water, or 1.2% of acetylene in air, which is lower than it's l.e.l.. So unfortunately enough this is not going to work without any water added, air just can't hold enough water, even at higher temperatures...:)

I doubt that even a very brisant charge could pulverize a 100 times it's weight of rockhard CaC2 into a very fine powder anyway...

[Edited on 14-2-2007 by nitro-genes]

quicksilver - 14-2-2007 at 17:57

One of the best places to look for material of this sort is "Fire Science" text books for undergrad arson investigation...some of it is really indepth.

mfilip62 - 15-2-2007 at 10:39

If you try to grind carbide you will definitly spoil it!
I tried once to putt grinded carbide inside tea bags,
so I can have instant potato gun "powder",butt it reacted
with H2O in the air instantly and become CaO or something....
Weather was wery dry,and grinder was hermetically closed!

So there is no question that it will rapidly "become" acetilene,butt how fast it depends on;
afther explosion,how much of explosive pertially becomes hot steam and that definitely is some kind of catslyst and how wet weather is!
be carefull,Iwish You luck!

P.S.;What if you crush it under benzin or something and make organic solvent/carbide paste or slurry mixture! Interesting?!

KemiRockarFett - 8-3-2009 at 14:38

Why not try to put finely grinded carbide around an ordinary explosive? Two cans in each other, explosive in the center can, and fine carbide powder in the bigger can.
When the explosive goes off the water vapour from the detonation gas will go through the carbide and produce acetylene at the same time.
A lof of options...
But the result will be more thermobaric...if it works,,

grndpndr - 8-3-2009 at 21:02

This post may not belong if not my apologys.

Just a thought but has anyone looked at reports of coal dust explosions in mining accidents and grain dust explosions occuring in grain handling facilitys?

The requirements/conditions for detonation versus deflagration are very well documented with extensive testing
determining optimum concentrations/specific materials even specific type of coal which will detonate rather than simply deflagrate.As anyone who was alive back in the '70's will attest particularly us midwesterners is that a grain dust explosion can be extremely destructive,crushing reinforced concrete structures with impunity.I would suppose flour
with its large nitrogen content would work as well if not better than grain dust fines.Its been awhile since I read a few of the reports which I saved as they seemed a real possibility for a successful enclosed at least dust/FA explosive.
Therin lies the problem however these explosions require confinement as one of the 5 legs of a successful dust detonation.fine if your target is a cave or a relatively open building but likely useless out of doors.:(

Suprisingly enough there is also only one type of coal which will detonate. Unfortunately I cannot recall the variety that will detonate under proper conditions or which dust, coal or grain contains the most energy however i do recall that common corn starch IIRC had the most energy upon detonation of the grain dusts.To be honest so much information is contained in the accident reports and investigations they are virtual manuals for construction of a successful device:o
[Edited on 8-3-2009 by grndpndr]

[Edited on 8-3-2009 by grndpndr]

497 - 8-3-2009 at 22:31

Few particulate fuels can achieve a real detonation (expecially unconfined). A few can but even then, the detonation is fairly weak compared to a decent liquid fuel. A possible exception here is fine Al powder...

It doesn't take much to knock down a building from the inside. Even a whimpy deflagration will do it.

If you want a real FAE, chlorinate some propylene glycol, epoxidize it with NaOH, and presto, ready made FAE fuel..

grndpndr - 9-3-2009 at 05:26

All due respect 497 but those who have survived dust explosions havent called them whimpy.Nor would the results of a dust explosion where reinforced concrete grain handling facilitys have been reduced to rubble could be called insignificant.

Granted where not talking the power of an engineered FAE
but a great deal of death and destruction have been caused by dust explosions.Generally accepted as fact now is that mysterious old coal fired luxury liner sinkings have been destroyed by coal bunker dust explosions.
1in thick hulls split open again isnt insignificant.

While Ill say again engineered FAEs contain a great deal of power to dismiss out of hand the not insubstantial power of a dust explosion seems out of character 497 particularly IF the literature hasnt been read.It seems akin to saying gas leaks in buildings produce insignificant power.That may be true compared to a military multi million $ engineered devices but the occupants are still dead and the building and immediate surroundings destroyed.

Im well aware this site is largely theoretical and thats well and good and in fact quite interesting.But so are the ideas/materials that are within the ability of the average experimenter to obtain and fabricate and finally the power contained in the dusts when the requirements for detonation are met is far from insubstantial, 200mph plus explosion/deflagration fronts, 90psi shockwaves lasting .045 sec insubstantial? I believe 1/2 the shockwave value alone will kill a human being w/90psi shockwaves destroying all but underground purpose designed bunkers.However as far as a dust explosion is concerned atomized metals do seem to meet the severe explosion rating for dusts while coal and
grain dusts less so.If cost is a concern!?

Dust is very likely the grandaddy of the FAE Idea.

[Edited on 9-3-2009 by grndpndr]
Edited ad infinitum correcting figures, toning down tenor of post.

[Edited on 9-3-2009 by grndpndr]

[Edited on 10-3-2009 by grndpndr]

497 - 13-3-2009 at 00:07

It's amazing what things will do when confined...

Yes, I agree dust explosions can certainly do damage, quite a lot, for sure. But personally I'm not terribly interested in things that require containment... Far harder to experiment with, and much less versatile..

Quote:

200mph plus explosion/deflagration fronts, 90psi shockwaves lasting .045 sec insubstantial?


Depends on what you compare it to... Compared to 4000mph and thousands of psi, yes, I still say it is insubstantial.. For a deflagration/dust explosion to do you any harm, you basically have to be in it.

There's nothing hard about demolishing a building, if that's all you need to do. A propane tank and an igniter are all it takes, no mystery about it.

Microtek - 13-3-2009 at 00:38

Have any of you looked through US4463680, "Method of generating single-event, unconfined fuel-air detonation"?

It details using diesel fuel in a non-sophisticated FAE design with a single central HE dispersing charge, and no delayed second ignition charge. The novel aspect of the invention is to use ferrocene or one of a few other compounds as a catalyst (2-10 % based on the amount of fuel). The catalyst is either dissolved in the fuel, or arranged in an annulus between the bursting charge and the fuel.

They also talk about making proof-of-concept tests in the lab with sub-ml quantities (apparently using pneumatics instead of HEs to disperse the fuel). Anybody know of a good source for ferrocene?

chief - 13-3-2009 at 10:51

One could use a coffee-mill with a built-in spark-plug to test for dust-explosions: The mill will create a fine dust within it, out of every sort of powder, eg. charcoal ... (as confinement maybe a thin one-way plastique-drinking-cup instead of the usual lid, much less dangerous and lets the energy away, so the coffe-mill is preserved; anyhow: Do from safe distance, since the quickly moving mechanical parts of the mill are dangerous enough)

Besides this could have a technical use someday: Diesel originally wanted to invent a engine running on coal-dust, not oil ..., but the use of otherwise useless heavy-oil worked out just brilliantly ...

If coal-dust or any other stuff could be utilized for running a car: This would be very great, since many such substances grow on the fields of any country, and do not have to be ordered from the Saudis ...

And what about the following ignition method: Abusing a magnetron, powering it by capacitor-discharge ..., for a multi-kW pulse, creating ignition with a 3D-distribution ... (hereby not patentable any more !)

[Edited on 13-3-2009 by chief]

497 - 13-3-2009 at 12:22

@Microtech. Yes, I've seen that patent. All the catalysts are too exotic/expensive for my liking.. Also I'm skeptical it works as well as they say, from what I've seen in a few papers about single event/catalyzed FAEs the results were marginal. But it would be so easy to test.. Get your ferrocene here.

Personally, I don't think a two event type FAE would be that hard to pull off. A friend of mine is close.

@chief. Burning coal dust in engines has been investigated very thoroughly. It doesn't work, they get fouled by the ash too quickly.

chief - 13-3-2009 at 12:50

@497: Maybe then sugar could be used: It gives no ash, and can be simply crystallized to that purity ...

Also: On the world there can be produced any amount of sugar, it's only kept expensive by cartels ; in reality , by the production-cost, it is very cheap ..., and renewable. Crystal-sugar contains only C, H and O, so no ash ...

497 - 13-3-2009 at 17:44

You could cover the world with sugar plantations and there still wouldn't be enough to begin to fuel the worlds vehicles...

It might not make much ash, but it might be hard to get sugar to burn anywhere near cleanly... Also it is not known for it's fast burning characteristics. It would have to be some VERY fine powder, and even then I doubt you would be able to get a whole lot of power out of it in an internal combustion engine..

grndpndr - 13-3-2009 at 23:38

Just this evening a documentary about renewables and alcohol revealed it required nearly the same amount of fossil fuel to produce an equivalent amount of alcohol.
I would expect farming sugar cane/beets would be equally as expensive in terms of resources.Personally think corn or any foodstuff used to produce fuel is a very poor way to goAs well the resulting ash from direct injection of coal dust in a traditional piston engine would make for a very short lived powerplant as was pointed out.Perhaps some other design to take advantage of the overpressure /wind speed.
Turbine of some type, with a precombustion chamber?Coal fired anything is a very dirty device so a mechanism for pollution control just might make such an engine size impractical?

As far as FAEs 497 I guess it depends on ones intentions for his device.iirc figures like that rival the effects of nuclear devices at varying distances, I for one would avoid exposure to anything approaching 90psi overpressure and 200mph windspeeds.An individual needent be IN the explosion to be killed by the overpressure or windspeed of the dust explosion. respectfully:)

[Edited on 14-3-2009 by grndpndr]

[Edited on 14-3-2009 by grndpndr]

497 - 14-3-2009 at 00:20

^ I totally agree with the first paragraph. If one was intent on burning coal to push their fat ass around, I would suggest an external combustion engine such as a Stirling cycle.. The burner might crap up fast, but at least the engine would stay clean.
Quote:
I guess it depends on ones intentions for his device.


That sums it all up well... And yes the gov't has thought about (maybe gone through with?) using FAEs to simulate small nuclear detonations..

chief - 14-3-2009 at 15:05

The world _can_ produce way more than it does -- as seen from the EU: Everything agricultural is regulated in such a way as to produce little enough so the prices stay up. Farmers even get government-money in order to do nothing;
of course distilling the alcohol out of anything consumes much energy ...

But sugar can burn quickly, as those sugar+chlorate recipes show ...

Never listen to the oil-is-best- propaganda: It comes from the same people who made oil-prices quite high last year ... ; now they are only down to prevent investments into other energies ... can't let them up for too long .... ; but they are gonna milk out the optimum amount of money out of everybody also in the future ...

grndpndr - 16-3-2009 at 05:00

Im geting dangerously far afield and yes I am disturbed by ranchers/farmers the largest entitlement group I am aware of driving new 1ton duallys to town for grocerys.But factually land must rest.ergo paid for planting nothing or preventing overgrazing which is extremely devestating denuding mainly national grassland thats been leased not owned by the ranchers yet treated as personal property when it comes to hunting etc on our land.Sorry for the rant.

Dust explosions rock! Ask the dead.:(

grndpndr - 17-3-2009 at 14:25

Back to FAEs particularly dust explosions I was curios as to whats needed to destroy a house from overpressure alone.

Apparently a stick built home suffering overpressure of 7-14
KPA will be completely destroyed.A concrete wall built of co unreinforced concrete block 30cm
thick or cast unreinforced wall will be destroyed by 10.35-38
KPA exterior overpressure.The figures were borrowed from nuclear blast effects,FAEs obviously far less lethAL less the radiation and effects of intense light/burns the effects of overpressure remain the same not inconsequential and possibly not needing confinement.

Appreciate the patent Microtek have to check it.A single event
FAE particularly if a inexpensive dust or fuel and catalyst can be used it would be quite useful.All respect an indoor dust explosion strategically placed and timed...

[Edited on 17-3-2009 by grndpndr]

[Edited on 17-3-2009 by grndpndr]

497 - 17-3-2009 at 16:57

Buildings, expesially houses, require *very little* overpressure from the inside to flaten them. Those numbers look high to me. More reasonable for outside overpressure, but there is a big difference. I seem to remember seeing that less than 1 psi of internal overpressure is required to destroy stick buildings, and around 3-5 for concrete buildings IIRC. The numbers are around, maybe in a patent, I can't remember exactly.

There is no need to worry about attempting a single event catalyzed FAE for a contained dust type explosion. The only point of using a catalyst is to replace the precisely timed initiator charge required to get a full detonation out of a true FAE. With a dust explosion, there is no detonation, thus no need for a high explosive initiator. Any decent flame, flash powder, thermite, etc, would work to ignite a dust explosion. It could probably be made to be a single event setup if one added Al or Ti powder to the high explosive burster (if there is one).

grndpndr - 17-3-2009 at 19:57

Thanks again 497.In fact the figures were indeed for external pressures.I apparently was to vague in my explanation.Thanks again all advice /input is greatly appreciated.I had however some interest in a actual fuel air explosion rather than a simple dust explosion.As we agree a dust explosion has its time and place when conditions are right and I cant think of a less expensive way to demolish a home etc.We do have abandoned homes from farmstead days but that may be overly ambitious lol really!!

497 - 18-3-2009 at 00:16

I often wonder what an entire building filled with stoiciometric oxygen-acetylene would look like going off...

Anyway, here's my rough draft of a plan for a *real* FAE (which has never been documented in the amateur community to my knowledge):

-Fuel: Diesel Cetane Improver. Depending on the brand, some contain 20-35% octyl nitrate (ethylhexyl nitrate actually) with the balance being mostly naptha, etc. This would make an ideal fuel when used straight out of the bottle.. The octyl nitrate could possibly be concentrated by boiling off the light petroleum products to increase its concentration up to 40-60%, but I doubt you'd need to do that. Alternatively, if you were extra hardcore, you could synthesize your own ethylene/propylene/butylene oxide.. About two liters of fuel needed regardless of what type.

-Fuel container: Two liter PETE soda bottle. Ideally it would be raised off the ground a few feet.

-Bursting charge: 5-20g ETN or equivalent electrically initiated with primary of your choice. Exact sizing of the bursting charge seems to be relatively unimportant..

-Initiator charge: 100-300g ETN or equivalent (the more brisant the better) electrically initiated with primary of your choice. Hard to say the minimum amount without testing. Initiator charge should be placed about 4-6 feet away from the fuel container, and on the same horizontal plane.

-Electronics: Remote fireworks display unit found on eBay, etc. Long range remote control. Can be easily programed to fire one charge (burster) and then the other (initiator) 100 milliseconds later. This is a good timing delay. I know how these work because a friend has one.

Hope that helps a little.. If I'm lucky I'll get to watch a similar setup in action soon.

Keep in mind the overpressure delivered at a distance could be equivalent to somewhere between 4 and 0.5 kilograms of TNT, depending on the fuel and conditions.

PS. I just found the attached file. Have fun.

[Edited on 17-3-2009 by 497]

Attachment: solid fuel FAEs.pdf (593kB)
This file has been downloaded 1432 times

grndpndr - 18-3-2009 at 04:26

Years ago when i worked seismograph I had electronic delay detonators of various delays,shame they were essentially wasted.
as in reqular nondelay caps.I would want to be a substantial distance from the oxy acetylene explosion filled a few balloons while oxy
acetylene welding a few times cant imagine an entire home filled with a correct mix!Heck a guy could put plastic over the broke out windows use a little caulk and foam little ciphering for mixture and...
doubt a fire truck could be summoned in time or even the fire /explosion discovered until smoke rising in the horizon.
Not a good style if one wanted to keep his hobbys private even though it would be some time before the Unfortunate "lightning strike" discovered.;)
Appreciate the file 497

[Edited on 18-3-2009 by grndpndr]

497 - 18-3-2009 at 07:18

I don't think there would be anything very solid left for the fire department to put out. :P

I thing I'm safe, considering I don't have the means to test a design like that now or any time soon. People publish far more "dangerous" ideas/designs all the time over at RS with no repercussions. It's not anything extremely original, just an adaptation of designs that our own military and patent service have published.

[Edited on 18-3-2009 by 497]

grndpndr - 18-3-2009 at 10:28

Me either its just a fun topic of discussion that just happen to enjoy.To actually commit such an act is so far from my comfort zone or need for kicks the very idea is laughable but the actual disussion god help me I do enjoy.

A middle age adolescent in that respect.Could be worse,I could be the local deputy who patrols our small town a few hours a week under arrest for essentially being a sexual predator against the civilians he was sworn to serve and protect but charged with 3 counts of rape ,.1of giving false info to states CID.:o

chief - 18-3-2009 at 10:44

Those 300 g of ignition-charge are quite much -- it's not a clean fuel-air-explosive then, but a 300g-charge -fuel-air- explosive ... ; what about more smaller charges, instead of the big one: Would it still work ?

A wire-frame with a lot of electrical sparking-points might provide the ignition, maybe 1 spark each cubic foot ... ; but would the effect be the same ?
Maybe the principle is different: The fuel is not the explosive, but only provides a atmosphere within which the HE-pressure-wave can travel with less decay ... ... because of the potential energy of the fuel ...

The fuel-atmosphere reduces the necessary compression work for the "ignition"-charge, since it's capable of self-compression ; thereby the ignition-charge gets more range ...

Maybe the fuel alone couldn't do it (?) even if it would be ignited at numerous points at the same time ?

I just hope that everyone here knows the Feynman-physicsbook-explaination about shockwaves (in the 1st of the 3 thick books)

[Edited on 18-3-2009 by chief]

chief - 18-3-2009 at 10:52

If my above theory would be wrong and the fuel _could_ undergo detonation even from ignition by numerous mini-sparks:

Then shaped charges could be made, abusing the possibilities of 3D-arrangement of the sparks ; maybe 3D-microwave-ignition would be possible as well (with some fuel-components that give easy plasma) ...

this then could give quite some sort of rocket-engine ... !

Microtek - 18-3-2009 at 14:56

From that article on solid fuel FAEs, flake aluminum seems to be a very effective fuel. I wonder then, since a 1:1 magnalium alloy is so brittle, how about packing a brisant HE inside a magnalium cylinder? Maybe the detonation would produce (and disperse) magnalium particles of a sufficiently small particle size that it would be useable for FAE purposes...

497 - 18-3-2009 at 15:24

Quote:

Those 300 g of ignition-charge are quite much


Yes 300g would be more than enough, for sure. But it all depends on how sensitive your fuel is, and how reliable you want the device to be. When the military was testing propylene oxide detonation in old quarys they used a spherical 1/2 pound C4 charge IIRC, even though propylene oxide is a very sensitive fuel. If I was going to try it, I'd start with a charge around 100g and if it worked, then maybe try smaller ones, if it didn't then I'd try increasing it's size.

Using sparks, flames, etc, is a good way to get a pathetic deflagration out of a perfectly good FAE cloud.. Not saying it would never work, but it would be a hell of a lot harder to get working, compared to synthesizing a few hundred grams of HE. As I understand it, the powerful shockwave from the FAE passes through the cloud virtually instantly (compared to most things) and basically forces the entire cloud to ignite at the same time, which is what allows the powerful detonation. When only a parts of the cloud are ignited (eg, by sparks) the flame front travels through the cloud relatively slowly and results in a deflagration of weak detonation at best. And that 100g of ETN would be minor compared to the main shockwave that followed behind it.

grndpndr - 26-3-2009 at 22:57

Quote: Originally posted by Microtek  
From that article on solid fuel FAEs, flake aluminum seems to be a very effective fuel. I wonder then, since a 1:1 magnalium alloy is so brittle, how about packing a brisant HE inside a magnalium cylinder? Maybe the detonation would produce (and disperse) magnaluminum particles of a sufficiently small particle size that it would be useable for FAE purposes...

Using the magnalianium alloy as a container the resulting detonation/blinding fireball ignitingtoDDT the fuelSuch as a flake AL.How about titanium /al alloy?supposed long lived ignition source? surround over the device suspended off the ground.I dont recall that the article advised containment was a leg of the detonation of AL flake?I wonder if an actual container would be needed made from the magnaluminum or simply a plastic bag one with the magnaliminum surrounding the HE and another surrounding the magnaluminum fine mesh flaked AL?Unless contemplating a projectile of course

iirc magnesium is not an inexpensive metal so experiments w/o mag.would be in order,same with titanium.

Flake AL-Pottassium perchlorate! that should accomplish some type of dust explosion? found in the FAE article just a quick mention never the less even if used like the black book
inspired dust explosive I would expect some extreme fireballs at minimum hopefully detonation out of doors.Ratios would be needed but a very small scale experiment now with snow on the ground would be safe.And IIRC theres a small concrete guard shack on National grassland.To bad no balls no blue chips.:( by the wat besides the small guard shack theres hundreds of concrete munitions igloos complete with several ton doors intact about tyhe size of a tennis court some 13-14 miles from town. Outside locking of multiton door the trest of the bunker covered with afew feet of earth.Until a cleanup in the late 90s shells from 20mm-155mm pluis would wash out of the hillside regularly.By regs they were supposedly burned to deflagration or detonation but not carefully.Just as in riussian areas of intense ww2 combat they still unearth projectiles use a double boiler and salvage the military he filling from the projectiles selling it on the black mkt.Please excuse the excessive edits!
[Edited on 27-3-2009 by grndpndr]

[Edited on 27-3-2009 by grndpndr]

[Edited on 27-3-2009 by grndpndr]

[Edited on 27-3-2009 by grndpndr]

497 - 27-3-2009 at 09:05

Quote:

I wonder then, since a 1:1 magnalium alloy is so brittle, how about packing a brisant HE inside a magnalium cylinder? Maybe the detonation would produce (and disperse) magnalium particles of a sufficiently small particle size that it would be useable for FAE purposes...


I am doubtful that it would produce fragments small enough to burn effeciently. I could be wrong though.. It would be easy enough to try..

On a somewhat similar note, I know it is possible to get a lovely thermobaric effect by detonating cylinders of laminated layers of [plasticized RDX sheet -- teflon tape -- aluminum foil]. That's the warhead the "Hellfire" missiles contain, apparently it works well. Not quite an FAE though.. Still, it shows that it is possible to use metals in forms other than powder.. I'll post the patent if anyone wants..

grndpndr - 27-3-2009 at 13:20

Quote: Originally posted by 497  
Quote:

I wonder then, since a 1:1 magnalium alloy is so brittle, how about packing a brisant HE inside a magnalium cylinder? Maybe the detonation would produce (and disperse) magnalium particles of a sufficiently small particle size that it would be useable for FAE purposes...


I am doubtful that it would produce fragments small enough to burn effeciently. I could be wrong though.. It would be easy enough to try..

On a somewhat similar note, I know it is possible to get a lovely thermobaric effect by detonating cylinders of laminated layers of [plasticized RDX sheet -- teflon tape -- aluminum foil]. That's the warhead the "Hellfire" missiles contain, apparently it works well. Not quite an FAE though.. Still, it shows that it is possible to use metals in forms other than powder.. I'll post the patent if anyone wants..


Please! post the patent! i am most interested in tyhe effect of the easily available teflon tape or other forms in addition to the flake AL.Whats your take on the AL flake and pott perchlorate as a dust explosive as per the file above?
(solid fuel FAEs.PDF 593kb)Very interested in any patents /files
with teflon/al as the fuel perhaps including ratios etc.mainly an excess of teflon or aluminum degrade/negate any effects.
My hope is for a single event FAE with an actual high order detonation preferably in as varyed a weather as possible,unconfined of course. thanks.I ws under the assumption the hellfire used mainly CSCs sophisticated tandem warheads possibly but wasnt aware of what would the teflon/al/essentially detaflex warhead be called?enhanced blast?I would assume its targets to not be hard targets like armor, perhaps buildings,bunkers soft vehicles.

[Edited on 27-3-2009 by grndpndr]

[Edited on 27-3-2009 by grndpndr]

IrC - 29-3-2009 at 00:16

I imagine you all think too much and therefore miss the simple and often best answers. The best FAE I have yet seen is non dairy powdered coffee creamer. The largest and most powerful FAE detonations in human history have all so far been grain dust (usually initiated by static electricity) as was mentioned in a previous post. Mythbusters did a hell of a good job demoing the creamer FAE. For initiation all they did was stick a lit flare at the mouth of their dust cannon powered by compressed air.

While fireballs were the result little thought is needed to achieve power, as in study of an implosion type fission bomb. Logic indicates the FAE inside the spherical explosive blanket is going to expand in a superheated state while delaying detonation until the cloud has mixed with enough air to reach stoimetric proportions (since it would fail to burn until enough O2 was present). Whether a delayed initiator of compressed piezo design in the center or use of self initiation of the heated expanding cloud for initiation is utilized (which would still be hot enough for enough time near the center), it seems on the surface either way the desired result would be reached.

I have always found it safer to invent these things in thought and let the uncle fester idiots actually try them. We already know that if the idea is a good one somewhere someones military R&D labs has already toyed with the idea. Or have they?



[Edited on 3-29-2009 by IrC]

497 - 29-3-2009 at 14:55

Here it is. Also I took advantage of the lovely new multi-attach feature and attached another very interesting patent about a hybrid thermobaric warhead...

I believe the main reason the Hellfire missiles use the laminated type warhead, is because it is much less sensitive to mechanical shock than the normal charge containing Al powder. They have to be extra insensitive to be able to punch through tank armour and detonate on the inside... I remember seeing a little slow motion video of a Hellfire punching through about three feet of reinforced concrete and detonating on the other side...

While we may not want a charge to be extra extra insensitive, the laminated design is still interesting because it allows the use of totally ubiquitous materials like Al foil and telfon tape. It could be especially useful if/when the government decides to regulate reactive metal powders more heavily.. I think it would be especially interesting if it was possible to simply make a loose spiral of Al foil and fill the gaps with a high powered liquid (or castable) explosive to get a comparable thermobaric effect to Al powder... It would be both safer and simpler/easier/cheaper.

@IrC, I can pretty well guarantee that every accidental "fuel-air explosion" involving a particulate fuel was a deflagration.. Personally, I doubt that you're ever going to get more than a fireball out of nondairy creamer..

Quote:

I have always found it safer to invent these things in thought and let the uncle fester idiots actually try them.


For a given explosive yield, fuel-air detonations (the two event style) are far safer than the equivalent quantity of HE. Simply because the burster and initiator must both be detonated synchronously, which is almost impossible to do accidentally.


Attachment: layered EBX warhead.pdf (170kB)
This file has been downloaded 1381 times

Attachment: Hybrid_warhead.pdf (124kB)
This file has been downloaded 1234 times


[Edited on 29-3-2009 by 497]

IrC - 29-3-2009 at 15:48

I think both types of FAE fuels have use. The lower impulse fireball fuels can be used as decontamination devices for bio-hazards where the structural damage is minimum.

grndpndr - 29-3-2009 at 19:58

was it in good ol mexico that a gas line ruptured in a large sewer filling several square city blocks with natural gas/propane.Townspeople were annoyed when they began detonating destroying entire city blocks ,the affected area looked like a warzone.Many deaths/wounded IIRC actually took them some time to determine the cause as the destruction was so intense and widespread.The solution I would have though relatively obvious.I dont care deflagration or DDT. videotape of a fire dept waiting a bit to long to ignite what they thought was diesel fuel poured in a basement was in fact gasoline, gave it the time to disperse(practice)
to what must have been near ideal ratios and the house demolished with splinters remaining and fortunately the guy tossing the flare miracoulously unharmed as the video looked as if the entire side of the home took him with the flying debris which while slow Im sure by HE standards was to fast for the eye w/o slo mo assist and even then it wasnt clear what happened to the fireman.Unassisted dust/gas explosions arent something to sneeze at w/200mph wind speeds and the real killer 90psi overpressure.

I dont claim alotta knowledge about the hellfire missile but my belief was it was intended as a large very long range anti-tank missile armed with a variety of warheads like the TOW but with 2-3 x the range possibly fire and forget with
tandem warheads etc but penetrating 3ft reinforced concrete just by the effect of kinetic energy?I believe youve mistaken a hellfire for a bunkerbuster.Only an air drpped bunker buster from altitude of at least 500lbs will penetrate 3ft of concrete by kinetic energy alone.Only the 120mm abrams firing APFSDS long rod DU penetrators will penetrate 3 ft reinf concrete or the armor of a modern mbt but not a lightly built missile whose intented use is penetration/destruction by means of chemical energy.








[Edited on 30-3-2009 by grndpndr]

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497 - 29-3-2009 at 20:44

Well they do weigh 100 pounds... and move 1000 mph...

But really, they don't have to penetrate all the way through, just enough to direct the explosion mostly to the back side. The warhead is only ~10 kg. And now that I see that they also make shaped charge variants, it is certainly possible that the video I saw was a shaped charge in action.

Here's some good info. They call it an "FAE" a few times, which is false, but other than that, it seems like accurate. Here's a nice video of one in action.

[Edited on 30-3-2009 by 497]

grndpndr - 30-3-2009 at 13:44

Sounds more like a squash head SC. obsolete against modern composite armor,reactive armor and spaced armor.
like the name the thin walled warhead impacted the target material'squashing' the explosive charge into something like a pancake.When tightly compressed against the target the warhead detonated setting up shockwaves overstressing the material and causing spalling to the interior of the heaviest tanks and causing large chunks of concrete to spall from the interior of hardened buildings at several hundred MPH still devastating against bunkers/std armor w/o penetration.

You likely saw an advanced warhead design 497 that used chemical energy rather than kinetic.Regards

I sure like the teflon/al Idea ,sadly I dont indulge myself any...:(
Really think you should view some grain dust explosions that have occurred in concrete structures.The effects are devestating ,reinforced concrete shattered if you hadnt known better youd have swore it was a HE demolition.
They peaked around the 70s but still occur in many different situations were flammable dusts can become dispersed and ignited.90 PSI isnt a fireball! Regards
OK i looked at the link,its a thermobaric warheaad intended for use against enclosed buildings/caves.Its accuracy meant to hit tanks at IIRC 5kilometers allows it to go through windows/doors cave entrances. It is as you say an enhanced warhead using some sort of metals 'increasing pressure peaks for longer durations than normal explosives' similar effects to a dust explosion but with all that power (Heat/pressure) contained in a small package[Edited on 30-3-2009 by grndpndr] Pott perchlorate/AL dust?

[Edited on 31-3-2009 by grndpndr]

[Edited on 31-3-2009 by grndpndr]

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NameWithheld - 12-4-2009 at 17:18

http://www.youtube.com/watch?v=xquGETNoRms

2 liters fuel in a standard soda bottle, 23% Isopropyl Nitrite, 23% Diethyl Ether, 54% Heptane

Approx 1.2 meter standoff at 1 meter elevation over hard packed snow.

0.080 second delay between burster and initiator.

Captured at normal speed with sound, and 600fps.

497 - 12-4-2009 at 17:53

It was even more impressive seeing it in person.. The videos just don't do it justice. But the high speed footage is nice, I love the second frame after the initiator fires, it's just a perfect spherical orange detonation cloud (the second to last still frame shown in the video.)

It was surprising to me how much damage it did to the hard packed snow below it. You can't really see it in the videos, but the snow is substantially cratered and pulverized for several meters around the initiator stand.

As the video says, hopefully more to come.

nitro-genes - 15-4-2009 at 07:28

Congrats! I think you are the first amateur that actually made a working FAE! :D

Care to elaborate a little more on the timing of the two charges, the fuel weight/explosive weight ratio, confinement and composition of both the dispersal and detonation charge? :)

I'm surprised that the fuel cloud was able to make DDT with only 2 liters fuel! I guess that is why you used the relatively large amount of IPN? Are you planning the same ratio's for the 20 liter charge? Maybe 10 or even 5% IPN would suffice in this case...

What is your opinion about the possibility of using methylated spirits with a good deal of dissolved ammoniumnitrate as the fuel? This would have been my fuel of choice since both are cheap and easily obtainable around here. Energy output would be somewhat less on a weight basis compared to your mix. It would be a simple mix-and-fire option, although I've never read about the performance of ethanol/methanol as the fuel in the available patents concerning FAE's...

Nitro-genes



NameWithheld - 15-4-2009 at 16:07

"Care to elaborate a little more on the timing of the two charges"

Radio transmitter with multiple channels, receivers programmed to specific channels (1 and 2). Transmitter set to send out signal on channel 1 at time X, channel 2 at time Y.

"the fuel weight/explosive weight ratio"

Fuel weight roughly 1400 grams, explosive burster roughly 9 grams.

"confinement and composition of both the dispersal and detonation charge? :)"

Dispersal charge pure recrystallized Erythritol Tetranitrate (ETN) powder in 11mm OD vinyl tubing, inside 12.7mm ID PVC pipe, inserted in the center of the fuel. Initiating charge was a small plastic bag of cast ETN.

"I'm surprised that the fuel cloud was able to make DDT with only 2 liters fuel!"

As I understand it, DDT refers to deflagration-to-detonation transition, the general process by which a subsonic combustion wave becomes a supersonic detonation front. In this case it would be the exact opposite. The initiating charge gave the dispersed fuel a shock wave, detonating it. This detonation front traveled through the fuel until it made the transition to a deflagration. Additionally, the amount of fuel is largely unrelated to its ability to detonate, in fact larger charges would have more difficulty fully detonating than smaller tests.

"I guess that is why you used the relatively large amount of IPN?"

Isopropyl nitrite is added to increase volatility and sensitize the mixture.

"Are you planning the same ratio's for the 20 liter charge? Maybe 10 or even 5% IPN would suffice in this case..."

The 20 liter charge is tentatively planned to be a mixture of roughly 2.5 liters Isopropyl nitrite, 5 liters hexane, 12.5 liters heptane. These are rough estimates, actual content may vary.

"What is your opinion about the possibility of using methylated spirits with a good deal of dissolved ammoniumnitrate as the fuel?"

Sounds feasible, but defeats the purpose of an FAE in some ways. For me the entire idea of an FAE is to utilize non-explosive fuels and take advantage of atmospheric oxygen in creating an explosion. Using fuels with high amounts of molecular oxygen content would defeat this to some degree, not to mention using something that's already a high explosive.

[Edited on 4-16-2009 by NameWithheld]

497 - 15-4-2009 at 17:13

I don't think adding AN would help at all for the sensitivity of the fuel cloud. Its not a particularly strong or unstable oxidizer, and it is insensitive to shock waves. I doubt it would add much/any to the power of the FAE, since all the oxygen necessary is supplied by the air, the AN may well be wasted.

I have never seen any mention of alcohols as fuels in all the military FAE literature I've seen. I don't see why it wouldn't work, but testing is the only way to know anything for sure.. "Methanol is a high octane fuel that is extremely resistant to detonation." Yes I realize this is in the context of an internal combustion engine, but similar principles may apply to FAEs...

User - 16-4-2009 at 11:22

Great achievement.
What kind of hardware did you use for the FAE ?

nitro-genes - 16-4-2009 at 15:10


-"As I understand it, DDT refers to deflagration-to-detonation transition, the general process by which a subsonic combustion wave becomes a supersonic detonation front. In this case it would be the exact opposite. The initiating charge gave the dispersed fuel a shock wave, detonating it. This detonation front traveled through the fuel until it made the transition to a deflagration. Additionally, the amount of fuel is largely unrelated to its ability to detonate, in fact larger charges would have more difficulty fully detonating than smaller tests."

I see what you mean, but wouldn't this mean that the initiating charge needs to be upscaled linearly with the amount of fuel used?

Pressure drops exceedingly fast with increasing distance from the initiating explosive, so I can't really see how the shockwave could propagate al the way through the fuel/air cloud without the reaction of the fuel/air mix itself adding energy to the shockwave to sustain it. This would mean that given the fuel/air cloud is of large enough size and sensitivity it would eventually sustain detonation on it's own, independant of the amount of initiating explosive.

-"]I don't think adding AN would help at all for the sensitivity of the fuel cloud. Its not a particularly strong or unstable oxidizer, and it is insensitive to shock waves."

I can't imagine that there is a lot of volatilization in those 80 miliseconds, moreover is IPN also characterized as an insensitive explosive, used for improving combustion in diesel engines. Wouldn't the insensitivity, stability and ability to mix with alkanes make IPN just a logical choice? Decomposition temperature of the additive is probably important analogous to thermobaric explosives, but this does not exclude a range of other possible additives IMO...

Anyway, can't wait to see the big one!...:D

[Edited on 16-4-2009 by nitro-genes]

497 - 16-4-2009 at 18:44

Quote:
but wouldn't this mean that the initiating charge needs to be upscaled linearly with the amount of fuel used? Pressure drops exceedingly fast with increasing distance from the initiating explosive, so I can't really see how the shockwave could propagate al the way through the fuel/air cloud without the reaction of the fuel/air mix itself adding energy to the shockwave to sustain it. This would mean that given the fuel/air cloud is of large enough size and sensitivity it would eventually sustain detonation on it's own, independant of the amount of initiating explosive.


No initiators need not be scaled up. Even if the shock wave from the initiator is not strong enough to initiate detonation in the entire cloud at once, it will begin a detonation wave in the vicinity near the initiator, which will, with proper types of fuels and fuel/air ratios continue to propagate through the rest of the cloud until it hits the outer edges were the mixture is too lean. There should be no deflagration involved, at least until the main detonation wave runs into an minor areas of too lean or rich fuel/air ratios. And size seems to be unimportant for all be the most insensitive fuels. I've seen patents for 225ml FAE charges!
Quote:
I can't imagine that there is a lot of volatilization in those 80 miliseconds, moreover is IPN also characterized as an insensitive explosive, used for improving combustion in diesel engines.


Actually yes there is substantial volitilization, and actually 80ms is pretty short, we will be using a longer delay next time. It is known that hexane nearly completely evaporates in less the 200ms after dispersion. It is far harder to detonate a fuel (with the exception of the most sensitive ones such as pure nitrates/nitrites or epoxides) that is not substantially evaporated. And the IPN I'm talking about (Isopropyl nitrite) is not explosive at all, while Isopropyl nitrate is the difficultly detonated and fairly feeble explosive cousin. The main reason the IPN is added, is that upon being subjected to a shock wave, it splits into isopropoxyl radicals and nitrogen monoxide. The alkoxyl radicals are apperently responsible for the powerful sensitizing/catalyzing effect that alkyl nitrate/nitrites have on fuels. Since the N-O bond is weak in both nitrites and nitrates, both nitrite or nitrate esters seem to work similarly.

Adding NH4NO3 to a fuel would simply result in small particles of it floating around in the cloud. I have a hunch that the particles would not even take part in the fast free radical combustion reactions that occur near the detonation front (considering some particles of fuel don't even take part.)
Quote:
Wouldn't the insensitivity, stability and ability to mix with alkanes make IPN just a logical choice?


Yes.. though that was clear.

Bikemaster - 18-4-2009 at 17:40

What is your camcorder to film 600 fps??? high speed camera can film up to 25,000 fps easily but they cost a lot, and other camcorder can film at max 60 fps...

497 - 18-4-2009 at 18:32

http://www.dpreview.com/news/0801/08010601casiof1.asp

Bikemaster - 19-4-2009 at 13:31

Thanks a lot!!

it more seem to be a camera that a camcorder but if it can shoot a 1200 fps:o i think it will be ok for 1200$:D

Elawr - 20-4-2009 at 21:37

Quote: Originally posted by 497  
I often wonder what an entire building filled with stoiciometric oxygen-acetylene would look like going off...



Hell, why settle for oxygen? What I'd like to see would be the setting off of an acetylene - ozone binary mix. If held in liquid phase at low enough temperature, could pure ozone possibly be contained long enough to allow its dispersal with acetylene liquid (or snow). Probably the detonation would be spontaneous, requiring no primer.

...it would be glorious! ;)

KemiRockarFett - 23-4-2009 at 14:14

May test with two litres of ordinary heptan/gasoline to compare the time scedules with the mix you already tried.
To increase the velocity in the fuel/air mix it could be of interest to add for example 1 -2 % TATP to the fuel.
The best way may be to create some acetylene under the "spray process" How? Maybe its possible by reacting the hot water gas from the first explosion with some finely grinded CaC2 to get C2H2 inmixed with the gas and air.
Probably the C2H2 will make the combustion goes faster all over the cloud.
Suggestions?

497 - 23-4-2009 at 14:57

If it's a hot day, you have a large initiator, and you get the timing right, you might be able to pull off a detonation with straight gasoline... It'd be interesting to see at least.

About the TATP, I very much doubt you'd get a noticeable increase in velocity by adding it.. I know of no fuel besides possibly hydrogen that will detonate at over 2000m/s in air. TATP might increase the fuel sensitivity a little, but I remember reading somewhere that organic peroxides were found to be ineffective sensitizers for FAEs, but it would be easy enough to try.

I must say, I seriously doubt you could generate enough acetylene quickly enough from CaC2.. But go for it if you think it could work.. If I was going to try anything with acetylene, it would be a cold saturated solution of it in acetone..

[Edited on 23-4-2009 by 497]

KemiRockarFett - 23-4-2009 at 23:37

Quote: Originally posted by 497  
If it's a hot day, you have a large initiator, and you get the timing right, you might be able to pull off a detonation with straight gasoline... It'd be interesting to see at least.

About the TATP, I very much doubt you'd get a noticeable increase in velocity by adding it.. I know of no fuel besides possibly hydrogen that will detonate at over 2000m/s in air. TATP might increase the fuel sensitivity a little, but I remember reading somewhere that organic peroxides were found to be ineffective sensitizers for FAEs, but it would be easy enough to try.

I must say, I seriously doubt you could generate enough acetylene quickly enough from CaC2.. But go for it if you think it could work.. If I was going to try anything with acetylene, it would be a cold saturated solution of it in acetone..

[Edited on 23-4-2009 by 497]


The CaC2 might be mixed with an explosive giving H2O as detonation product. ( An explosive not reacting with the basic carbide-ion under storage) AND hopefully the formed acetylene will NOT detonate/decompose in the same time its formed.... or it does and when this is not working :)

497 - 24-4-2009 at 16:49

You could probably do it.. Explosively disperse water and CaC2 together. You'd have to have a long delay to wait for the acetylene to form and mix with the air. It depends on whether the CaC2 could react much before it blew away or settled to the ground.. hope you have a lot of CaC2.

KemiRockarFett - 24-4-2009 at 23:49

Quote: Originally posted by 497  
You could probably do it.. Explosively disperse water and CaC2 together. You'd have to have a long delay to wait for the acetylene to form and mix with the air. It depends on whether the CaC2 could react much before it blew away or settled to the ground.. hope you have a lot of CaC2.


Probably its better to use several initiation points instead of one as in the movie if using pure gasoline. A cricle of initiation charges connected with detcord, this to ensure a near simultaneous combustion of the entire cloude.

grndpndr - 27-4-2009 at 16:33

Quote: Originally posted by 497  
I often wonder what an entire building filled with stoiciometric oxygen-acetylene would look like going off"

[Edited on 17-3-2009 by 497]


I was looking at another thread with acetylene /oxygen as the mixed gas and deflagration or detonation velocity and whether by implication a detonator would be required.I found the results from a respected det vel. table dowloaded from this site and another i cant recall. Acetylene/oxygen @2/1 gas mixture det vel = 2660mps,2/3 ratio, 2720mps,3/1
ratio 2320mps VOD.Again whether by ignition or detonation initiated the chart doesnt mention.Safe wager would say very little left of a home let alone a reinforced bunker if detonated from the interior.Even if detonated from the exterior a large device retaining optimum overpressure would do substantial damage to a hard target and most likely kill all the occupants unless equipped with sealed compartments similar to bank vaults.:o JMHO

Leander - 30-4-2009 at 12:43

First of all, I'm Dutch. Please don't mind the misspelled crap. Im not an idiot.

I have some experience with thermobaric explosive charges based on a high explosive center charge with a surround of plastisized metal power.

Some successful test have been done by me and other members of a dutch forum called pyroforum.nl, with for example a 30 gram plastic bonded PETN centercharge along with a surround of 40 grams 70/20/10 Al/KClO3/PIB @> 1.7 gr/cc. This is all based on US patent 6.955.732.

This setup is capable of fully burning the aluminumpowder over a (relatively) extended period of time producing roughly 20 kBars of pressure. Since I don't own a high speed camera its hard to give any data on the exact time it takes for the charge to burn the completeness.

Would it be possible to use such a setup to ignite a FAE? If you can extend the burning time of your alumnium long enough for the cloud to mix with the air properly, it might be possible to use such a charge to spread the fuel, as well as igniting it at the same time.

Unfortunately the burning time of such scarges cannot be delayed by using for example coarser aluminumpowder, since from my video material the effective range of such charges seems to be limited to about 80 cm. @7000 m/s thats uuhhm, not really long. :D Further from the charge there is simply not enough pressure and heat.

As far as I know the burning time of a thermobaric charge cannot be extended much by the reason mentioned above. The time it takes to ignite the fuel cloud cannot be speed up either since, according to tests by other members here at SMDB, is takes at least 50 milliseconds to properly spread and vaporise the fuel with air.

If a design like this would work, it wouldn't take precise timing of seperate desperion and igniting charges. Also, there's a possibility to add more oxigen to the atmosphere by raising the oxidiser content of the earlier mentioned surround charge. This would result in a more evenly mixed cloud (oxygen from the inside out!), and therefore more effective combustion.

A possible drawback, or even failure of this idea would be that the surround charge is incapable of reaching enough atmosferic oxygen because of the 'blanket' of gasoline or whatever is in its way to burn.

Any idea's? Any data on the 'burning time' of thermobaric charges? According to US patent 6.955.732 the combustion takes from 10 to 50ms to complete.






[Edited on 30-4-2009 by Leander]

[Edited on 30-4-2009 by Leander]

[Edited on 30-4-2009 by Leander]

grndpndr - 10-5-2009 at 17:43

Maybe I misunderstand but the surround charge of a thermobaric warhead contains its own oxidizer/fuel so outside atmosphere isnt nesscessary in fact the attraction of thermobaric warheads is they work in low/no 02 enviroments.
So I do not understand how a gasoline fuel cloud surround of a thermobaric warhead would starve it(thermobaric warhead) of oxygen?

[Edited on 11-5-2009 by grndpndr]

[Edited on 11-5-2009 by grndpndr]

NameWithheld - 10-5-2009 at 19:57

Quote: Originally posted by grndpndr  
Maybe I misunderstand but the surround charge of a thermobaric warhead contains its own oxidizer/fuel so outside atmosphere isnt nesscessary in fact the attraction of thermobaric warheads is they work in low/no 02 enviroments.


Thermobarics, more or less by definition, utilize atmospheric oxygen.

"Thermobaric weapons distinguish themselves from conventional explosive weapons by using atmospheric oxygen, instead of carrying an oxidizer in their explosives."

"Volumetric weapons include thermobaric and fuel-air explosives (FAE). Both thermobaric and FAE operate on similar technical principles. In the case of FAE, when a shell or projectile containing a fuel in the form of gas, liquid or dustexplodes, the fuel or dust like material is introduced into the air to form acloud. This cloud is then detonated to create a shock wave of extended duration that produces overpressure and expands in all directions. In a thermobaric weapon, the fuel consists of a monopropellant and energetic particles. The monopropellant detonates in a manner simular to TNT while the particles burn rapidly in the surrounding air later in time, resulting an intense fireball and high blast overpressure."

Etc.

497 - 10-5-2009 at 22:41

Quote:
Would it be possible to use such a setup to ignite a FAE? If you can extend the burning time of your alumnium long enough for the cloud to mix with the air properly, it might be possible to use such a charge to spread the fuel, as well as igniting it at the same time.


Probably not. It's a great way to make a fireball though. Very similar to the sort of thing they use at the Boomershoot. There will not be enough time for the fuel to mix in the proper proportions with air before igniting. Even if it did mix in perfect proportions, the chances of achieving a detonation from a weak ignition source like burning Al would be slim.
Quote:
the surround charge of a thermobaric warhead contains its own oxidizer/fuel so outside atmosphere isnt nesscessary


There is never enough oxidizer added to fully burn the metallic fuel. It is simply added to increase the ease/reliability of ignition of the metallic fuel. Probably 75-90% of the oxygen needed comes from the air.

The reason metalized thermobarics are popular for enclosed oxygen poor spaces is not because they carry their own oxygen, it's because they use a metallic fuel that can effectively pull oxygen from almost anything that contains it (such as CO, CO2, H2O, SiO2, etc). On the other hand, hydrocarbon fuels used in FAEs cannot do that, so they must be used in the open with sufficient air.

grndpndr - 10-5-2009 at 23:41

Are you saying to me name withheld that thermobarics do not contain an oxidizer?

If so I think your more confused than I.
patent 6955732 and many other related patents describe oxidizers such as AP,AN,
etc etc. In amounts up to 36% in combination with various reactive metals.AL,MG,Boron Titanium. Often with binders that contribute to the detonation like nitrocellulose

497,your maintaining FAEs do not contain reactive metals in your last paragraph?

With all due respect Im not exactly sure whos the most confused here?

Namewithheld flatly states no oxidizers are used in thermobarics all patents to the contrary and your convoluted explanation doesnt hold water either regards the reactive metal claim,Im well aware FAEs must be used in the open or 02 rich enviroments, weather permitting,another reason for thermobarics but FAES use reactive metals as well as thermobarics.You yourself when we discussed dust explosions explained that AL dust was the only dust IIRC that would make a detonateable FAE.All due respect gents but theres holes here a man could walk through. Why not just dispense altogether with oxidizers /explosive in thermobaric surrounds and rely on residual / chemically scavenged 02 in all cases assuming reactive metals are so efficient in scavenging oxygen from any source?Mood?Dubious!
However it is late perhaps Ill dream of solid rocket fuel components that detonate w/o 02 and SFAE.


[Edited on 11-5-2009 by grndpndr]

[Edited on 11-5-2009 by grndpndr]

[Edited on 11-5-2009 by grndpndr]

Leander - 11-5-2009 at 01:04

The amount of oxidizer available in such burst surround setups is by far not enough to reach oxygen balance.

When talking about aluminized explosives, there´s simply no such thing as oxygen balance! As 497 already mentions, reactive metals can rip off oxygen from most combustion products produced by the detonation. Magnesium and alloys can even react with nitrogen. In theory, if the total amount of oxygen present in the charge compared to the amount of aluminum powder is 2 : 3, you can get full combustion. This is only limited by the fact that above 30% inerts charges become more difficult to detonate. Also, to make the metals react you need a sufficient temperature and pressure, than practically cannot be reached this way.

In real life you can really see a significant difference in composition of thermobaric charges. In for example torpedo´s, where charges detonate under water away from any atmospheric oxygen, they can contain up to 60% AP. The only reason this is not done in above ground situations, is because apparently the metals can react with atmospheric oxygen quite effectively.

grndpndr - 11-5-2009 at 02:13

Clearly Im behind the times.Ive never heard of a thermobaric torpedo. I am also still skeptical of AL having the ability to scavenge as it were 02 from any oxygen containing materials.
Admittedly Im a rank amateur here having read few papers or patents concerning the properties of AL in SFAE/thermobaric devices and never seeing the properties attributed to AL mentioned in any I cant argue a point Im unsure of.So,I appreciate your kind responses,thanks.:D
The AL reaction,basically'stealing' oxygen, o is this akin to what happens in a thermite reaction to the iron oxide?
[Edited on 11-5-2009 by grndpndr

[Edited on 11-5-2009 by grndpndr][Edited on 11-5-2009 by grndpndr]

[Edited on 11-5-2009 by grndpndr]

497 - 11-5-2009 at 15:40

Quote:
497,your maintaining FAEs do not contain reactive metals in your last paragraph?


True, an FAE could contain a metallic fuel.. But AFAIK there has never been one used in practice that contained much more than some kind of hydrocarbon mixture. I didn't say FAE's can't contain metal powders, just that they rarely if ever do in practice.

NameWithheald never said they couldn't contain oxidizers, just that they never contain a very significant amount of the oxygen needs of the metallic fuel.

Yes its kinda like a thermite reaction. Basically Al is a very strong reducing agent, strong enough to reduce most any common oxygen containing compounds, and even release a good amount of energy too (not quite as much as it would if reacting with O2, but its not a bit difference usually).

markgollum - 11-5-2009 at 16:09

If you are wondering if one metal or other fuel can "strip" the oxygen from another, an Ellingham diagram is very useful. Basically it plots the thermodynamic equilibrium vapour pressure of oxygen above the fuel/metal as a function of temperature. The substance with the lowest oxygen partial pressure at the temperature of interest is the "winner" in the fight for oxygen. You can use the data to quantitatively determine equilibrium constant assuming that the activities of the solids are 1 (not always the case, there things you can do to affect the activities, reducing them or even increasing them beyond one, but this is (to me) a complex topic).
An important note, Ellingham diagrams give thermodynamic solutions and do not consider kinetics, so it is possible that if the reaction conditions are not maintained for a sufficient time, then the equilibrium constant may be far from realized. However, metal powders typically have rapid kinetics which become exponentially more rapid as both temperature increases or particle size decreases. Also, I beleive that in thermobaric/enhanced blast devices, appreciable metallic fuel is likely in the gas phase, making for exceedingly fast kinetics.

A simple google search for "Ellingham diagram" brings up some excellent diagrams along with a tutorial.

grndpndr - 11-5-2009 at 21:29

Thank for all the informative replies.Its very much appreciated
particularly the collective patience shown.:)

[Edited on 12-5-2009 by grndpndr]

[Edited on 12-5-2009 by grndpndr]

497 - 12-5-2009 at 23:56

Here is a very useful document. I've been looking for it for a while now, finally got it. Thought I'd share it..

"Of the more than 25 different homogeneous additives tested, the strongest ignition promoters, by far, were found to be the alkyl nitrates and nitrites..."

"The ignition delay at 1000*K, of Shelldyne-H or H-HCPD was reduced from 180 and 110 milliseconds to 3.5 and 5.3 milliseconds respectively, upon the addition of 25 volume percent n-propyl nitrate."

"Other additives such as H2O, N2O, CO, H2 or peroxides, esters, polyethers and alcohols had little or no effect on
promoting the autoignition of various hydrocarbons..."

EDIT: The damn file is slightly too big to attach. I'll post a link as soon as I can.

[Edited on 13-5-2009 by 497]


Here's the file I mentioned above. It's worth a read.

http://savefile.com/files/2104562

[Edited on 17-3-2011 by quicksilver]

Bikemaster - 27-1-2010 at 12:16

Do it append any probleme to you, because your youtube account have been shout down???

-=HeX=- - 23-2-2010 at 11:21

497: Check your U2U's.

I reckon AL powder MAY make an alright FAE. I tested a bunch of single step FAE's as per the patent - Kudos to Carbonfiend who found the optimal ratio to be 6% Ferrocene, 47% Diesel, 47% Ether. No second charge, and they went to full detonation

simply RED - 1-3-2010 at 01:08

Hex, this is extremely interesting. May you provide more information on the actual experiments with this one-event FAE.

How powerful is it, does it really detonat and not just burn?

-=HeX=- - 12-3-2010 at 14:37

IN our experiments, also done by Carbonfiend, we found, in long grass, the thing blasts away 15cm radius with a mere 15ml, set off with 0.75g AgN3. However, I got a radius of 19cm using 0.70g RDX, 200mg DPNA primary.

Philou Zrealone reckons it may be ineffivient, but hey, it works especially in 1 litre amount set off by 100g RDX. That made a HUGE BANG but it was in the open. I felt a pressure wave, and I was about 600m away.

I personally think at least SOME makes the DDT. Soon I will build a plywood 'house' (i.e. box) and see can I blast that to shreds

Lord Emrone - 17-3-2011 at 07:46

I have the idea to make a fireball with gasoline. 1 liter of it on top of a 200 gr ANFO charge by example. I could use BP or FP but I'm used to detonations, so I'll use that.

I was thinking to use several grams of red phosphorus tightly packed in tape and place that on top of the gaz bottle. The shock will cause the RP to burn and burst out of the tape and light the gaz cloud.

Anyone other ideas or suggestions ?

Jimbo Jones - 17-3-2011 at 09:58

Yeah. Shredded to pieces, dusted with fine aluminum powder Teflon tape. You will also need heavily aluminized booster, but that’s ok. The main problem will be the choice of good fuel. A charcoals and liquid oxygen are supposed to be nice and spectacular mixture.

quicksilver - 18-3-2011 at 07:46

Exceptional book that deals with ancient examples of fuel/air concepts from beginning of recorded history: "GREEK FIRE, Chemical Warfare In The Ancient World" {A. Mayor, 2003}ISBN-158567-348. One of the better historical accounts of chemical-bio usage in antiquity. Was one of the best [bibliographic-notation & researched] books of it's genre' I have read in a damn long time.
Points to ancient period of air-fuel usage testing from natural occurring (naphtha & lower hydrocarbons) dispersal mechanisms.

Rosco Bodine - 18-3-2011 at 08:24

Quote: Originally posted by Lord Emrone  
I have the idea to make a fireball with gasoline. 1 liter of it on top of a 200 gr ANFO charge by example. I could use BP or FP but I'm used to detonations, so I'll use that.

I was thinking to use several grams of red phosphorus tightly packed in tape and place that on top of the gaz bottle. The shock will cause the RP to burn and burst out of the tape and light the gaz cloud.

Anyone other ideas or suggestions ?


Titanium coarse powder granules or magnesium turnings in a baggie on top of the charge and underneath the gasoline should ignite and remain burning long enough to make a good igniter for the dispersed vapor cloud of gasoline which otherwise will probably not be ignited by the charge alone.
Coarse graulated magnalium might work also.

[Edited on 18-3-2011 by Rosco Bodine]

Lord Emrone - 19-3-2011 at 09:39

@Jimbo Jones : pieces of Teflon tape dusted with fine aluminum powder ? Is that tape an oxidizer ?

@Rosco : I only have fine Al and magnesium powder. I'll try with RP.

Jimbo Jones - 20-3-2011 at 02:31

Quote: Originally posted by Lord Emrone  
@Jimbo Jones : pieces of Teflon tape dusted with fine aluminum powder ? Is that tape an oxidizer ?


It’s just more exotic form of thermite.

White Yeti - 2-8-2011 at 06:56

This is probably a stupid question, but how do you ignite the cloud of explosive vapour when the first charge blows up the container and everything in its proximity? This means that the second igniter has to be far away from the conventional charge, somewhere inside the cloud. Could you use something similar to an electric arc (not a spark gap) to ignite the cloud? Since the mix will not ignite when it is fuel rich, the arc would only ignite the mix when the right fuel air ratio is established. Also, wouldn't the heat of the initial explosion be enough to also ignite the fuel air mix?

hiperion42 - 1-7-2012 at 10:41

Quote: Originally posted by White Yeti  
This is probably a stupid question, but how do you ignite the cloud of explosive vapour when the first charge blows up the container and everything in its proximity?


The energy of the dispersal charge is almost completely absorbed and converted
into the outward movement of the fuel. It is therefore possible to
have the initiating charge located very close to the fuel.


46848644.jpg - 66kB


[Edited on 1-7-2012 by hiperion42]

matheusfredrich13 - 23-7-2012 at 21:01

A Fuel Air Explosion is achieved by using a blast to disperse the 'Fuel' into the air and then igniting the fuel cloud allowing all the 'fuel' to burn within a few milliseconds.

Fuel Air Explosive's rely on the oxygen in the surrounding air, rather then self oxidizing. The fuel is dispersed into the air to forming a cloud of very small droplets, and exposing a large amount of the 'Fuels' surface area. When the fuel cloud is ignited the 'Fuel' is able to burn almost instantly due to the fact that its in very small droplets. The smaller the droplets are the faster the fuel cloud will burn, this is the same as with Flash Powders or Black Powder.

Common fuels like gasoline, kerosine and diesel will not be able to achieve the Fuel Air Effect. To achieve the Fuel Air Effect you will need to use faster burning fuels such as Isopropyl Nitrite, Diethyl Ether or Heptane. Their are many other fuels that are suitable for use in a FAE but i don't want to mention them all. :P

Here is a great video of a True Fuel Air Explosion uploaded by AnonymousUploads (who sadly had to shut down his account due to a explosives related injury) :(
Here is the link: http://www.youtube.com/watch?v=7dW1qkBg8sM

I hope you find this useful and if you have any questions please ask :D

hiperion42 - 24-7-2012 at 06:41

Quote: Originally posted by matheusfredrich13  


Here is a great video of a True Fuel Air Explosion uploaded by AnonymousUploads (who sadly had to shut down his account due to a explosives related injury) :(
Here is the link: http://www.youtube.com/watch?v=7dW1qkBg8sM

I hope you find this useful and if you have any questions please ask :D


Maby you should go study a little bit extra before giving more advise.

While namewithheld's test was admirable it was not a full detonation.
The camera was running at 600fps and is played back at 30p which
means every second watching the movie is seeing 50ms elapse.
A fuel air cloud detonates in less than 10ms.
The cloud in the movie deflagrates for more than 200ms.
I recall he used a bag of cast etn of unknown quantity to initate the cloud.
Maby it was to little i don't know.

Again i respect the testing he did alot.

http://www.youtube.com/watch?v=j9xCgNdZPKk

[Edited on 24-7-2012 by hiperion42]

matheusfredrich13 - 24-7-2012 at 19:10

Yes, the FAE in the video i linked to did burn slower than the Fuel Air Cloud in the video you linked to. This could be because the fuels used in the videos were different. Or because the dispersion charges were different sizes. Either way the Fuel Air Cloud in the video i linked to still burnt at a abnormally fast rate, and you can clearly see the increase in blast pressure. The fuel might not have detonated as fast as in the video by Discovery Channel but it still did detonate.

[Edited on 25-7-2012 by matheusfredrich13]
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