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the freshmaker
February 24th, 2001, 03:03 PM
In the "favour flashpowder" discussion someone said that flashpowder would only deflagrate from a fuse, but detonate from shock - a HE.
(please don't discuss if flash will det from fuse, again!)
If I use a detonater/booster will it then detonate more powerfull than from fuse?
How powerfull is it then?
Will all kinds of falshpowders detonate?

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You can't survive the life!

Jumala
February 24th, 2001, 08:26 PM
I“ve seen a TV science show where they lit 0,2 g of a aluminum and perchlorate mix (silver colored Al powder) with a match.
It sounds like a pistol shot wich means its burn rate must be higher than 1000m/s = detonation. The same effect was shown with a 100g quantity. It was a strong detonation.

When you use sulfur additional in the mix the burnrate will be slowed down very much.

BoB-
February 25th, 2001, 05:03 AM
Any Chlorate or Chlorate distant cousin could potentially detonate, and some are unstable enough to detonate from deflegration.

the freshmaker
February 25th, 2001, 05:46 AM
Is Permanganate-flash unstable enough to detonate from shock. I will try it today. maybe I will take some pics of it.

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You can't survive the life!

the freshmaker
February 25th, 2001, 06:53 AM
Hmmmmm! I have just tried to detonate 20gr. Permanganate flashpowder. I filled a papertube with one open end with 20gr. flash and placed a small but very powerfull firecracker/bomb in the middle and then covered the open end with tape.

I'm not sure if it detonated but it was VERY loud and VERY powerfull. I firered it about 250m from our house, and only 5sec. after it blew up I could hear my mum yelling my name.
(my mum is used to some big booms comming from the forest, but this time she was totally fucked) She said the windows and the floor were shacking!!! http://theforum.virtualave.net/ubb/smile.gif

sorry I didn't get any pics this time, but maybe later.


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You can't survive the life!

blackadder
February 25th, 2001, 10:02 AM
How could you hear your mum calling your name if you were 250m away? You're mum must have shouted really loud!

Oh yeah, and what was the permanganate flash composed of? was it just KMnO4 with Al?

the freshmaker
February 25th, 2001, 12:34 PM
well I think the wind was blowing from the house down to me.......or else there wasn't 250m...but something near that.

I was using 12g KMno4 3gr. sulfur and 5gr. Al

Anthony
February 25th, 2001, 04:03 PM
A firecracker is not a detonator.

the freshmaker
February 25th, 2001, 04:18 PM
NO shit Sherlock! http://theforum.virtualave.net/ubb/smile.gif
It worked as a booster charge.

Anthony
February 25th, 2001, 07:44 PM
You said:

"Is Permanganate-flash unstable enough to detonate from shock"

You were trying to detonate a secondry high explosive by shock - using a firecracker - sounds like the role of a detonator to me.

How are you even sure the KMNO4 flash detonated? The heat from the burtsing firecracker would have been enough to ignite it.

J
February 25th, 2001, 08:40 PM
Don't know why I bother really, but just a safety warning: KMnO4 is such a strong oxidizer that mixtures made with it can go off by themselves. Try mixing some with Glycerine if you don't believe me.

Also, it is definitely shock sensitive. Try shooting a SMALL quantity of Permanganate flash (mixed onsite, you don't want it going off when you're carrying it) with an air rifle...

J

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"If the aquarium water has to be drunk don't waste the fish. In fact they'll probably be the easiest to eat even if you don't need the water. The cat is next in the pot." - John 'Lofty' Wiseman

the freshmaker
March 1st, 2001, 01:23 PM
Is Permanganate flash a secondary HE Anthony??
I DIDN'T say it detonated -but it was a very powerfull explosion. My point was if i gave the flashpowder a powerfull shock it would maybee detonate and as J said it is very shock-sensitive! and if it is VERY shock sensitive then a firecraker would be enough

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You can't survive the life!

Anthony
March 2nd, 2001, 04:13 PM
Off the top of my head I don't know, but it wouldn't suprise me if it is. I thought that by the fact that you were trying to detonate it that you already knew it was a HE?

Mr Cool
March 2nd, 2001, 05:33 PM
Not technically a secondary high explosive, just a shock-sensitive low explosive.

the freshmaker
March 2nd, 2001, 07:51 PM
When used with a fuse= Low explosive

When used with a detonator= (Weak) HE

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You can't survive the life!

Jumala
March 2nd, 2001, 10:14 PM
In my military time we have had training hand grenades (DM 12) made from cardboard and styrofoam. They were filled with a type of flashpowder(only a small amount).
When such a device goes off near you, you can“t use your ears for a hour or more.
You hear only a continuos "beeeep"

DM 12 devices have no detonators! Only a chemical delay ignitor.

A pistol shot isn“t as loud as a DM 12 so it is a detonation (< 1000 m/s).

sadsakjoel
March 4th, 2001, 01:46 AM
Today I have had sucess detonating flashpowder: One commercial firecracker was place on the ground and lit, soft, quiet noise. When we sticky-taped more smaller fireckrackers to it and shoved it under a bin, It was fucking loud! there wasn't much left of the smaller one's except 1 or 2 of the 9 didn't go off. I was surprised to find them into powered cardboard and not much else. Yes I am pretty sure of detonation.

J
March 4th, 2001, 08:03 AM
I don't think you can conclusively prove that it was a detonation, merely the composition is shock sensitive.

J

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"If the aquarium water has to be drunk don't waste the fish. In fact they'll probably be the easiest to eat even if you don't need the water. The cat is next in the pot." - John 'Lofty' Wiseman

outsider
March 4th, 2001, 01:42 PM
You should read the thread "flashpowder used as detonator" as well. Flashpowders consisting of (per)chlorate and aluminium detonate when confined. And they don't need a shock to detonate just a fuse. And I think permanganate flashpowder has the same properties: it detonates when confined and initiated with a fuse. And this would make it a primary high explosive (but not a very good one: sensitive,low VoD, low power).
Just put it on a piece of metal (steel, copper, aluminium), lite it: if it produces a dent it detonated.

Anthony
March 4th, 2001, 02:22 PM
"Flashpowders consisting of (per)chlorate and aluminium detonate when confined"

That may possibly be true of some flash powders but not most. Commercial flash is potassium chlorate/Al and it does not detonate. If lit unconfined it goes "poof" as does permanganate flash.

A pyrotechnics forum is the best place to ask about flash detonating. They spend loads of time argueing about it.

Sadsakjoel, it was louder because you used 9 crackers instead of 1 http://theforum.virtualave.net/ubb/wink.gif

firebreether
March 4th, 2001, 09:32 PM
Chlorate mixes are much more unstable than perchlorates, so I think they could potentially be detonated. Either way guys, whether flash can detonate or not, it still goes ka fuckin boom and thats all there is to it.

sadsakjoel
March 5th, 2001, 05:57 AM
Anthony- yes we did use 9 but only 1 had a fuse, and I thought maybe they detonated. i don't really know much about flash powders

outsider
March 5th, 2001, 12:23 PM
Just put 'em on some thin metal sheet (preferrably copper) and see what happens! And that you can detonate 9 at one time by just lighting one is also proof they detonate! The first one produced a shock that set they other ones off.

Mr Cool
March 5th, 2001, 12:44 PM
That's not a proof of detonation - it merely proves that flash is shock sensitive.

Mr Cool
March 6th, 2001, 03:49 PM
Oh, J already said that. Sorry.

outsider
March 7th, 2001, 08:07 AM
And how the hell is the shockwave produced that set the other 9 off ?
I just take a wild guess, but I think it must be the one that was ignited. And when you ignite a firecracker and a shockwave is produced that detonates all the others it was attached to (all in one time), it must have detonated, don't you think?
Just put one of those firecrackers on a copper plate and see what happens! The shockwave(!) will produce a dent! And you can try to produce such a dent with firecrackers filled with blackpowder (or some other mixture that doesn't produce a shockwave) and the result will be zero! Not even a kilo of blackpowder will produce a dent. So you can test it or take it from me: flashpowder made of (per)chlorate/aluminium and permanganate mixtures detonate when confined and ignited by fuse (but they are low power, low VoD (1000-1500 m/s), unstable and sensitive).

[This message has been edited by outsider (edited March 07, 2001).]

firebreether
March 7th, 2001, 03:52 PM
In KIPE it describes the Na or KClO3 + Vaseline mix. It also say you can substitute Al powder for some of the vaseline. I think this is kind of like flash. but it is very oxidizer rich so not exactly. It says you can get a Det. Vel. of around 3000 m/s. I assume this mix must be detonated with a cap. So If flash can change from deflagration to detonation of detonate period a small salute or firecracker should detonate the KClO3 + Vaseline mix. If it doesn't detonate I don't think it could.

Mr Cool
March 7th, 2001, 05:47 PM
Just because flash dented the plate DOES NOT mean it detonated! It just means it produced a large pressure, not necessarily from a detonation. Normal firecrackers don't do it because gunpowder is shit.

The KClO3 / Vaseline mix operates completely differently, because it is set off by a detonator which detonates the KClO3. If you used a detonator on normal flash it might very well detonate the KClO3 in it, but it will not detonate from flame. Thinking about it, the shock from the first one burning might have been enough to detonate the other 9, but it's morte likely that it just caused them to ignite and explode.

outsider
March 8th, 2001, 10:41 AM
Yes, KCLO3/vaseline is a different story. That mixture detonates when a blasting cap is used. And you can't even ignited with a flame: it won't even burn. And adding aluminium powder doesn't make it a flashpowder. By the way did any of you think about why it's called a flash powder? That's because when ignited by flame and unconfined it burns very quickly (in one flash) and produces a flash of bright light. So even unconfined it has a high burning rate. And when confined the reaction is even faster and deflagration becomes a detonation. See the similarities with AP? Unconfined: burns quickly, confined: detonation. Of course this does not proof firecrackers filled with flashpowder detonate when ignited by fuse, but I'm just trying to convince you people that they do. By the way, that they do produce a (clear/sharp) dent IS proof they detonate because it proofs that a shockwave was produced (pressurewaves of non detonating explosives don't have the power to produce a dent. Only detonating explosives produce such a dent. And with high enough VoD the metal will not only be dented but shattered as well). And that you can set a pack of firecrackers off all at one time(!) IS proof also of detonation. Believe it or not. By the way if you still don't believe it I would suggest reading a book about explosives.

outsider
March 8th, 2001, 02:56 PM
I recommend "The chemistry of powders and explosives" by T.L. Lewis: "mixtures of potassiumchlorate and red phosphorous and various other substances" are listed as primary explosives.

[This message has been edited by outsider (edited March 08, 2001).]

firebreether
March 8th, 2001, 03:42 PM
So is the concensus that it does detonate or it doesn't. I cast a vote for it detonating. What does everyone else say? How about deflagration to detonation. I cast a vote that it can because it is so unstable. I know voting won't give us the true answer but lets see how it turns out.

PS Outsider. Just because when confined doesn't mean it's like AP and will detonate. Almost any explosives burn rate is increased with higher pressures, some more than others. flash might be very sensitive to pressure yet still burn fast unconfined. (I don't think this is very likely or I don't even know if it is possible)so maybe this is what is happening. Though I think you're right when you say this. but don't jump to conclusions, let people decide for themselves whether or not to accept flash detonates. But do it after all things are considered.

Oh an also, someone said that because the firecracker produced a shockwave that ignited the other 9(or detonated depending on what you believe)it mustve detonated. That is NOT at all proof that the original one detonated from fuse. It proves that the firecracker exploded. Whupdedoo. When an explosive ignites it builds up very high pressures in its chamber. When pressure is enough it breaks the containers walls and the pressure is neuralized by the extremely fast release of gas to the outside. This gas is moving fast away from the source. Kind of like a wave. It hits something and pushes it in the direction that the wave is going. When the wave hits it it produces a shock. SHOCKWAVE. A weak one but none the less a shockwave. BP does this too. But BP doesn't burn fast enough to create a strong shochwvae from exploding it container. Maybe flash burns very fast and the shockwave that set the others off was from the crackers walls rupturing not the flash detonating. But I still think it detonates because of the extreme sensitivity of Chlorates mainly. I just want to represent both sides in the matter.

[This message has been edited by firebreether (edited March 08, 2001).]

Mr Cool
March 8th, 2001, 05:04 PM
Denting a metal plate IS NOT PROOF OF DETONATION!!! It is merely proof of a high pressure released in a short time. OK, the flash MIGHT have detonated, but nothing you've said so far proves it. And the fact that it set the others off is also NOT PROOF OF DETONATION. The flash in the tube burns, creating pressure. This ruptures the casing, creating a shock wave which pushes on the walls of the other firecrackers. This squashes the powder inside, raising the temperature and causing them to ignite and burst their containers.

firebreether
March 8th, 2001, 10:51 PM
Oh and one last thing. I think it can detonate, maybe even from a fuse although this might not be what happened or happens all the time I don't know. BUT when a low explosive ruptures a container it can only build up the pressure that bursts the container. When a HE detonates it creates many many times that. This is why it can blow bigger. That is also why it creates a real shockwave. I guess I'd agree that is why it will dent the Cu plate.

Anthony
March 9th, 2001, 07:26 PM
"Not even a kilo of blackpowder will produce a dent"

I promise that a kilo of BP in a cardboard tube would blow the fuck out of a bit of sheet metal. If it can rip it to pieces, it can dent it.

I think there is a very simple way of settling this: How are firecrackers classed? Is it 1.4G or as a HE???

outsider
March 10th, 2001, 08:06 AM
I cannot go explaining it again. Read a book. Some people seem to lack even a basic knowledge of explosives (the rupture of a container by high pressure produces NO shockwave!) And firecrackers filled with flashpowder are classed 1.1 (mass explosive) (read other thread about flashpowders used as detonator)

Mr Cool
March 10th, 2001, 09:09 AM
Of course it creates a shock wave. If it didn't you wouldn't hear a bang. A shock wave is just a wave of pressure, which is the same as sound waves.
Get an education.

Microtek
March 10th, 2001, 10:13 AM
Well there is a lot of faulty logic in this thread. I won't comment any further on that though, but simply say in response to outsider that while detonating explosives create a shockwave, so do gunshots or clapping your hands sharply.
Also there is nothing to say that a low explosive can't be shock sensitive so, the experiment with the nine firecrackers is inconclusive as well.
As for the plate dent test, you need to use very light confinement and not too large amounts of explosive to be able to conclude anything useful.
Just so everything is crystal clear:
None of this proves that flash does NOT detonate, it only points out that the question of detonation has not been settled.

PS. I know others have said all this earlier in this thread, I just want to add my support to the argument.

outsider
March 10th, 2001, 12:31 PM
I don't have to prove anything. Scientist have done that a long time ago. I was just letting you people know what those scientist found out. But you people are a little hard to convince so I suggested you to read some books about explosives.
And that's very necessary because some of you don't know some basic fundamentals about explosives. A shockwave is not a pressurewave for instance. And about education: I have had some. But maybe this the wrong forum for serious scientific discussions. Maybe here we should just talk about "loud fuckin' kaboom explosions" and "very loud fuckin' explosions".

10fingers
March 10th, 2001, 04:53 PM
Yea, who cares if it detonates or deflagrates as long as you get a big KA-BOOM. It seems that this topic has been done more times than necessary. Never definitively.
I have a suggestion. Take two equal amounts of flash powder and test them on a thin metal plate, one lit by fuse and the other with a detonator. They should be lightly confined, paper tube or similar to prevent scattering of the powder. The detonator should be small in relation to the amount of powder so as not to effect the results.
If the flash powder detonates then I would think that the dent would be larger than the sample lit by fuse.

Anthony
March 10th, 2001, 08:38 PM
Outsider, in practically every post you've made today, you have said that people lack a basic understanding of chemistry and should read some books.

I may not be an expert when it comes to explosives, but I know that both LE's and HE's produce a shock wave, just one of them is super sonic and the other is not.

This is the place for serious scientific discussion, but you seem to be getting stroppy just because people won't take your word. The subject of whether flash detonates is a common one amoung pyros and many hours get wasted argueing over it. So I suggest you get that stick out of your arse.

J
March 11th, 2001, 08:12 AM
This forum IS a place for serious scientific discussion. Outsider, if you have any sources for your information please state them, 'books' isn't very helpful.

As Anthony said, this discussion has arrisen before many times on various pyro discussion boards, I've never seen a conclusion.

J


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"If the aquarium water has to be drunk don't waste the fish. In fact they'll probably be the easiest to eat even if you don't need the water. The cat is next in the pot." - John 'Lofty' Wiseman

outsider
March 11th, 2001, 08:22 AM
You don't have to take my word. But you should take the word of serious scientific evidence and theories. But you people don't, that's why the discussion is going on and on. But it's a useless discussion because it's already clear which flashpowders detonate under what circumstances. And the discussion becomes very unclear when people start talking about things they don't have any knowledge of (some don't have a clue what they are talking about and should stick to "wow, that was a loud fuckin' kaboom" and shut up) or use all sorts of terms that they don't know the meaning of. One example of many is the word "shockwave". It's used for a lot for different things in this forum. Even clapping your hands would produce a shockwave (why not clapping your hands then, for initiating an explosive, it would be much easier). You can't discus about explosives when people don't even know the difference between sound, explosion, pressurewave and shockwave.

Microtek
March 11th, 2001, 08:55 AM
There you go again with your faulty logic;
just because A and B share one characteristic does not mean they will share another.
Let's make it real clear: Just saying that clapping hands and detonating explosives both produce shockwaves does not imply that they are both capable of initiating secondary explosives; it was exactly the point of my argument that they don't.
And YOU think that WE are thick-headed?

outsider
March 11th, 2001, 09:13 AM
(I Just cant admit I'm wrong instead I'll waste space here)

[This message has been edited by PYRO500 (edited March 12, 2001).]

the freshmaker
March 11th, 2001, 11:13 AM
I actully heard that ammonia triiodide can detonate if you claps your hands near ithttp://theforum.virtualave.net/ubb/smilies/smile.gifhttp://theforum.virtualave.net/ubb/smilies/smile.gif

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You can't survive the life!

Mr Cool
March 11th, 2001, 11:27 AM
Clapping hands produces a shock wave.
A sharp sound like a clap is a sudden rise in air pressure. A sudden rise in pressure is a shock.
Maybe you'd like to educate me, and explain what the difference is between the shock wave from a detonator or explosive and the clap from clapping your hands, except the magnitude?

Anthony
March 11th, 2001, 02:24 PM
"But you should take the word of serious scientific evidence and theories" - you have failed to quote or link to any of this "serious scientific evidence" so for all we know you're making it up or could have miss understood it.

"some don't have a clue what they are talking about and should stick to "wow, that was a loud fuckin' kaboom" and shut up"

If you want to insult someone, do it properly and use their name.

blackadder
March 11th, 2001, 06:39 PM
This is getting a bit annoying. We should be wasting hours of time arguing over whether flash detonates, not arguing over who has the more knowledge.

Enough, until outsider can prove that clapping your hands DOESN'T produce a shockwave, and until outsider can show us his "books", then what he is saying is rubbish.

I/we don't want outsider to be hated, he possesses valuable knowledge about explosives, and that's the whole point of this forum. We don't want to lose him. After he's proved that what he's saying is true, or admitted he's talking bullshit, all these "arguing" posts should be deleted.

Correct me if I'm wrong, but isn't sound itself a mini-shockwave? The shockwave reverbarates through the air, and your eardrums percept these vibrations, and send them to your brain which decodes them.

Mr Cool
March 12th, 2001, 02:30 PM
That's exactly what I think.
Well, I'm not going to argue anymore, but if Outsider comes up with some proof I'll gladly admit that I'm wrong, I just don't think I am.
It is a common misbelief that just because something makes a bang when unconfined, it detonates. This is not entirely true. It often is, but not always.

outsider
March 14th, 2001, 08:57 AM
OK, let's begin with the definition of a shockwave: the term shockwave is used to describe the physical effect that takes place in a high explosive when it detonates. A shockwave travels through the explosive material and delivers the energy for the material to react. By this reaction a lot of heat and gases are produced that expand with a lot of speed and force. This produces the PRESSUREwave. So it's the shock that makes the explosive material react. And a pressurewave is produced as a result (by the end products of the reaction). A shockwave is sort of like a blow of a hammer on a hard object that travels through the object with a certain speed.
A shockwave is also only for 1-2 inches effective: by this I mean it cannot cross an air gap and the (shattering!)effect of this (high power, high velocity) shockwave is only noticed to about 1-2 inches around the explosive. The pressurewave has no shattering effect but produces very high pressure which force can push/destroy objects near the explosive (or around the explosive). Now sound, explosion and pressurewaves have some similarities but it has clearly nothing to do with a shockwave. A shockwave is something completely different and should not be confused with pressurewave.
Clear definitions are a must for a discussion.
Now, I did(!) recommend a book for some to read: "the chemistry of powders and explosives" by T.L. Lewis. In there "mixtures of potassiumchlorate and red phosphorous and a lot of various other substances" are classed as primary explosives(!). The conclusion that firecrakers filled with flashpowder consisting of (per)chlorate and aluminiumpowder detonate when ignited by flame and confined is based upon a lot of arguments.
1. It detonates unconfined when iniated with a cap
2. It produces a shockwave(!) that dents a metal plate
3. It detonates other firecrackers taped to it (mass-explosive)
4. M-80's can be used to initiate high explosives (see other thread)
5. They're illegal in some countries because they detonate and are thus listed 1.1 (mass-explosive).
6. All the other arguments I told you.

So it's not MY faulty logic or bullshit.
I can be wrong and I am stubborn but if I'm wrong I'll admit it. But I think I came to the right conclusion, considering all the arguments in favour.

firebreether
March 14th, 2001, 03:36 PM
I think a shockwave can go more than a few inches, it just depends how much power is behind it. If you Det. 20 g RDX compared to 200 g of it than the 200 g det will produce a shockwave that is effective much further.

Microtek
March 16th, 2001, 04:40 AM
You're still doing it. If we are going to get anywhere with this argueing, we must both use proper logic. You aren't so we can't.

No further comments from me before there is some kind of development in this thread.

the freshmaker
March 16th, 2001, 08:57 AM
The following text is taken directly from the book: A Professional's Guide to Pyrotechnics - Understanding and Making Exploding Fireworks. (good book)

"One research paper indicates a velocity of propagation in the neighbourhood of 1,300 m/s for a p.perchlorate/aluminium flash mixture. Compare this velocity to with the figure of 4,450 m/s reported for TNT in THE CHIMISTRY OF POWDER AND EXPLOSIVES. The 1,300 m/s figure should be taken as an approximate velocity for flash explosion arrived at under certain, specific conditions rather than as an exact characteristic for all flash mixtures. Furthermore, the velocity of the detonation is only one criterion used to to classify explosive materials; it is not an accurate representation of the total power of an explosive material, but is a good criterion with wich to begin an examination of any explosive......"


1,300 m/s ......thats a detonation, right?

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You can't survive the life!

10fingers
March 16th, 2001, 10:28 AM
Oh Good! That settles it!

outsider
March 16th, 2001, 01:07 PM
Yes, velocity of detonation is only one property of an explosive. BUT a very important one! But first of all let me say that we were discussing if flashpowder detonated (flashpowder consisting of (per)chlorate and aluminium powder; used confined and ignited by flame). I am glad you found the information. I didn't know where I read it but all the other arguments made me conclude the same anyway. But now we can stop argueing (about this subject anyway).
Now about your remark. The velocity of detonation is very important because the higher the velocity the faster the energy of the explosive is released. And that makes a lot of difference in the effect or power: when all energy is released in a short time the power is very high. When released slow (low VoD, or with an explosive that doesn't detonate but deflagrate (="burning" :without producing a shockwave: the reaction is going by the heat transmitted through the explosive material. And you speak of "burning rate" to say something of the velocity of the reaction (blackpowder confined has a burning rate of about 300 m/s) . And this is NO shockwave. You must NOT confuse "burning rate" with "VoD". "Burning rate" is used for low explosives. "VoD"is for primary or secundary high explosives that detonate. So to be clear: BP has a burning rate of 300 m/s. And flashpowder has a VoD of 1,300 m/s.)
The difference in power is clearly illustrated by the following example: NC can detonate as well as deflagrate. And 1 kg of NC that detonates has the same energy as 1kg that deflagrates. But you can tell the difference in power! All the energy is released in one time when NC detonates AND a shockwave is produced. So it doesn't have only greater power (of the pressurewave), it also has the shattering effect of the shockwave. So it's fair to say that with increasing VoD (not burning rate) the power increases, because the difference in energy(!) of different explosives material isn't so great: the energy of a kg of BP can be compared with a kilo of flashpowder or even TNT. The power(!) and effect depends merely on the kind of reaction (detonation or deflagration) and the speed of the reaction (VoD and Burning rate respectively).

Mr Cool
March 16th, 2001, 04:59 PM
Doesn't flash have a BURNING RATE of 1.3 km/s, not a VoD of 1.3 km/s? Are you saying that if something burns at greater than 1 km/s, then it detonates?
I thought that even if it burnt at, for example, 2 km/s, it was still just a deflagrating low explosive (although a bloody good one!), such as BP (but obviously faster). I thought a detonation had to have certain specific features: a shock wave, immediately followed by a decomposition zone, then a reaction zone, then the detonation products. This is why I think flash initiated by a fuse burns, and by a detonator detonates, because if it is ignited by a fuse there is no shock wave. I know primary explosives ignited by fuses can detonate, but this is because the sudden rise in temperature breaks down some of the explosive, creating a sudden release of gas and a shock wave which detonates the rest. A sudden rise in temperature, in my opinion, would not cause enough of the flash to decompose quickly enough to create the shock wave required for detonation, because it takes a significant amount of time to warm up the components enough for them to react. The oxidiser would need to melt before it could get hot enough to decompose and oxidise the Al, and this would hold the temperature at this point for a certain amount of time, before the temperature could increase enough for the Al to burn. This makes the reaction sluggish compared to that of a primary explosive ignited by flame, where a sudden rise in temperature to about 200*C can decompose it.
It would be nice if someone had a high-speed photograph of flash detonating/burning, to settle this once and for all. Then we could see the waves travelling through it if it detonated, and this would be absolute proof. On a different topic, does anyone know how those high speed photographs of detonations are produced? High-speed X-ray spark photography? They look like X-rays, not normal photographs.

Also, it can be generally said that in detonating explosives, the detonation products flow in the opposite direction to the propogation of the reaction, whereas in deflagrating explosives the products flow in the same direction as the propogation of the reaction, so if anyone knows which way the gases flow this would be useful.

zaibatsu
March 16th, 2001, 06:22 PM
How fast would you need the shutter to open? In my camera (not particularly expensive) you can set the shutter to 1/6400th of a second, i'll try and get a catalogue and look at the top-end Nikons.

(just looked, the Minolta Dynax 9 (about £1149.90 (?!? quite cheap)) takes photos at a speed of up to 1/12,000th of a second, but only at a rate of 5.5fps)

Anthony
March 16th, 2001, 07:07 PM
I'm sorry but I do not consider that conclusive proof.

"One research paper indicates" - most or all research papers need to agree for it to be accepted as truth. I could write a paper on how flash doesn't detonate, it might not be true but I could still make the above statement.

"arrived at under certain, specific conditions" - "specific conditions" could be a blasting cap. The reference does not state how the flash was initiated, be it fuse or cap.

"1 kg of NC that detonates has the same energy as 1kg that deflagrates. But you can tell the difference in power!" - if they release the same amount of energy then they have the same power since "power" is energy.

How about if two firecrackers where taken and pushed into soft clay, one is ignited by fuse and the other initiated by a blasting cap. Obviously the effect of the cap would have to be taken into account. It would be like a lead block test, the charges could be tried in holes drilled into a concrete block (concrete should be more consistant than natural rock).

I think that test would produce fairly conclusive results, anyone agree?

c0deblue
March 17th, 2001, 02:34 AM
I don't know whether any sort of flash will detonate, but how about an objective test to determine the answer (the following is only an idea - I'm not sure of its validity in these circumstances).

Proposed Test:

1. Fill a fairly long piece of tubing (perhaps as long as 8 feet) with the flash mixture in question.

2. Place an electric detonating device at one end of the tube, and in the other end an electric ignitor identical to the one used in the detonator. Insure that both are in intimate contact with the material under test, but mount the detonator in such a way that it will only ignite or detonate the flashpowder without (itself) pressurizing the tube from the detonator end. For example, place the detonator in a position parallel to the tube with a section of the tube cut away, rather than in an axial position (with the detonator inserted in the tube end).

3. Stake the tubing so it's straight and mark the end points on the supporting surface for later reference.

4. Simultaneously fire the detonator and the ignitor using a series circuit (to insure simultaneous initiation).

5. In the same manner used when measuring the VoD of high explosives, observe the line created at the convergence of the two propagation fronts and note the position of this line relative to the original starting points.

Assuming that in the same material under the same conditions the velocity of a detonation wave would be much faster than simple flame front propagation, then if the line is equidistant from the ends it may be concluded that the material only deflagrates, whereas a line further in distance from the detonator end would indicate detonation from that end and deflagration from the other. Additionally, knowing the standard burn-rate for the tested composition (as determined independently) would allow detonation velocity (if applicable) to be calculated.

Are there any reasons a test such as this wouldn't at least yield ballpark data?

Any thoughts?

[This message has been edited by c0deblue (edited March 17, 2001).]

J
March 17th, 2001, 08:19 AM
Anthony: Power is not the same as energy. Power is a function of time and energy.

I don't know much about commercial detonators/igniters, but wouldn't it be very difficult to get them to initiate at exactly the same time? I can see that two detonators of the same make and from the same batch would, but surely there would be a slight time difference between a detonator and an ignitor? I'm assuming a wire being heated by a current is the method of initiation in each case. Or wouldn't the small time difference matter?

What if the flash detonated at both ends?

J

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"If the aquarium water has to be drunk don't waste the fish. In fact they'll probably be the easiest to eat even if you don't need the water. The cat is next in the pot." - John 'Lofty' Wiseman

[This message has been edited by J (edited March 17, 2001).]

outsider
March 17th, 2001, 10:23 AM
Why test it? It is already tested. The results are known. The flashpowder mentioned has a VoD (!) of 1.3 km/s. Not a burning rate because a shockwave is produced(!) And I don't think that the burning rate can reach a 1000 m/s or even higher (and if it can, it would still be a deflagration if the proces is continuated by heat and not by shock. It's the proces that takes place that defines the character of the explosive (detonating/deflagrating) not the speed!). I thought I explained it clear enough.
By the way there's a simple test: a shockwave has certain properties. E.g. it has a shattering power. You can see if a shockwave is produced by setting explosives off on(!) (not tamped) a metal plate. When a dent is produced or the metal is shattered you know a shockwave was created (with a low VoD and high VoD respectively).

Anthony
March 17th, 2001, 11:06 AM
It has already been tested? What? Where are the results? A COMPARITAVE test is needed to prove anything.

Unless you can conclusively prove that it does detonate by heat ignition then we will conclude that it doen't detonate.

Mr Cool
March 17th, 2001, 11:23 AM
I think the photographs used something like a high power X-ray machine, and X-ray film. The shutter of the camera was open all the time, but the film was insensitive to normal light. Then the X-ray machine was operated by a spark gap allowing a sudden pulse of HV, which caused an X-ray flash that was very short (0.5 nS. In that amount of time, light can only travel 6". Pretty bloody fast.) but very intense to darken the film. The X-rays passed through the explosive, and hit the film, showing differences in pressure due to refraction. X-rays were used because you can get much shorter bursts than with normal light, from a flash bulb, because of the way they are made.
I don't think that a normal camera could do it well. It would be blurred, and also I have no idea how you'd open the shutter at the right moment.

c0deblue
March 17th, 2001, 01:48 PM
J: I don't think the small time difference (if any) should matter in a test line of this length, since the distance "handicap" couldn't be more than the length of the detonator anyway (or its diameter in the case of the parallel orientation assumed for the test). Since both bridge-wire ignitors are identical and energized in series, both will reach initiating temperature at the same time. The only difference might be the time it takes for the detonator to initiate a shock wave response in the material under test.

If the material were to detonate from both ends then the test wouldn't reveal anything, but I'm assuming for the sake of argument that a bridge wire ignitor wouldn't produce detonation.

You're correct to point out the distinction between power and energy, but didn't you mean to say that *energy* is a function of time and power? E.g. Watts = Power, whereas Watt/Seconds = Energy.

J
March 18th, 2001, 08:43 AM
You're quite right! I suppose since the two main equations for KE and PE involve velocity/acceleration I should have realised.

I don't think the flash will detonate from plain ignition either, but I'd like to be proved wrong.

J

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"If the aquarium water has to be drunk don't waste the fish. In fact they'll probably be the easiest to eat even if you don't need the water. The cat is next in the pot." - John 'Lofty' Wiseman

outsider
March 18th, 2001, 09:12 AM
How much prove do you guys need?!

Microtek
March 18th, 2001, 01:09 PM
Mr Cool: I'm sure you're aware of this since you point out the distinction, but I'll just have to point it out anyway:

In a detonating explosive the products travel in the direction of propagation. Opposite for deflagrating. Which is why you must place your cap in the side of the
high)explosive that is furthest away from the target.

Anthony
March 18th, 2001, 03:38 PM
Well, the conclusive results of some comparitive tests would be proof enough.

PHILOU Zrealone
April 4th, 2001, 11:50 AM
A detonation is a shockwave but of a certain kind.... as mentionned a clap in the hands is a shock wave but the difference is not only the intensity but the speed of it.
So when speaking of a detonating explosive, usually we speak of a explosive with a shock wave produced and sustained by itself (eventually with the help of a detonator) but at a rate superior to the speed of sound trough the solid (in a gas like the air the velocity of sound is like 350m/s but in a solid like glass or granit it can be 3000m/s and in metals as high as 5000m/s).
Usually everything happens in the shock wave regio as soon as it has passed all products have reacted. It is almost like one end of the explosive don't know that a shock wave is traveling in its direction.
Now when we talk about low detonating explosives it is a little bit tricky since it is the speed of sound accross the solid that produce the friction wave igniting the stuff; the time of reaction and the reaction layer is much larger than in a fast detonating explosive.Thus the frontier is not clear except that we consider that over 2km/s is a detonation!

Here is what happens to a fast detonating explosive taken in ultra fast photography; one end is unreacted while the other is making a cone of fumes like < and dissipating very fast the products of reaction
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII-
IIIIIIIIIIIIIIIIIII<O
IIIIIIIIIII<O
III<O
I<O
O
Here is what happens in a deflagrating or low detonating explosive:
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII-
IIIIIIIIIIIIIIIIIII<<OOOOOOOOO
IIIIIIIIII<<OOOOOOOOOO
III<<OOOOOOOOOO
I<<OOOOOOOO
OOOOOOOO
Products have not yet finished their reaction when the wave is passed and react further without a fast dissipation of the products.

One thing I wanted to say also is that the oxydiser in your flash powder can influence the VOD or the BR; You can't expect
Hydrazine nitrate or perchlorate/Al mix to behave similarly to NH4NO3 or NH4ClO4/Al mix or to KNO3 or KClO4/Al mix since in the last one KClO4/KNO3 aren't detonating explosive while NH4NO3/NH4ClO4/NH2NH3NO3 and NH2NH3ClO4 are.
HN/Al mix should reach the 8km/s while AN/Al only the 3-4km/s and KClO4/Al 2-1km/s....

------------------
"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"

PHILOU Zrealone
April 4th, 2001, 11:57 AM
Shit those < give me troubles when I forgot a space.
IIIIIIIIIIIIIIIIIIII-
IIIIIIIIIIIII < O
IIIIIIII < O
III < O
I < O
O
IIIIIIIIIIIIIIIIIIIIII-
IIIIIIIIIIII < < OOOOO
IIIIII < < OOOOOOOOO
III < < OOOOOOOOO
I < < OOOOOOOO
OOOOOOO

J
April 4th, 2001, 03:30 PM
I can purchase NH4NO3 easily and cheaply, and I was thinking about whether it could be used in flash. I've consulted the PFP database and another formula collection, and can't find it used for flash. I seem to remember reading somewhere that it is dangerous to mix it with Al. Is this due to the fact that NO3/Al will produce heat when mixed, or is this yet another incompatibility of NH4NO3? I know it is incompatible with some other metals (Cu).

I've read that Al is a sensitizer of NH4NO3. Does this mean it makes it easier to detonate (requiring less primary explosive) or is it sensitizing to the extent that the mixture is unstable?

J

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"If the aquarium water has to be drunk don't waste the fish. In fact they'll probably be the easiest to eat even if you don't need the water. The cat is next in the pot." - John 'Lofty' Wiseman

Anthony
April 4th, 2001, 06:13 PM
Yeah, NO3s + Al in general are "to be avoided". I don't think it's a serious reaction though (like ClO3/S) a bit or boric acid would probably cure it - but don't quote me on that!

zaibatsu
April 6th, 2001, 09:18 PM
J, although I am not experienced in this field, I believe it sensitizes it, requiring less primary explosive, like Al in KClO3/Vaseline does.

------------------
Handguns don't kill people... Half as well as full-auto
Visit me at www.surf.to/eliteforum (http://www.surf.to/eliteforum)

JB
April 8th, 2001, 11:46 AM
I attempted to detonate NaClO3 + sugar + petrolium jelly last night with a detonator I made using a copper pipe filled with a mix of flash powder and about 180 paper caps because one article I have reads : "Mercury fulminate can be found in toy paper caps for use in a cap pistol. The quantity in a paper cap is about 1/10 of a grain. There are 15.4 grains in a gram so approximately 154 of them contain one gram".
When I inserted the det. unto the plastique and put this into a strong container, then set this off on a field. The report was a sound like a pop rather than a bang, but the visul effect was quite spectacular from the small amount used. Later my parents told me that it was quite loud, and even my neighbours came to the door. What I am enquiring about here is - did the chlorate plastique detonate or did it just ignite from the detonator? And though I only heard a pop/crack sound, was there a shockwave sent through the ground that would have been heard louder to those in houses than where I was stood out side? Also did the flash powder possibly detonate from the paper caps? I am quite intrigued by this result, and could anybody be able to explain this. I will have pictures shortly of the detonator setup and my method of the plastique manufacture if anyone is interested.

J
April 8th, 2001, 01:25 PM
I'd say a detonation was extremely unlikely. For a start, paper caps contain Armstrongs mix, not Fulminate. Unless the article was extremely old, you've been mis-informed. Either that, or the author was confusing caps with 'throw downs', which contain a TINY amount of primary explosive. Even if you took a thousand of these, you'd have to somehow extract the primary before they could be used to initiate anything.

I suspect that if you had left out the sugar, it wouldn't have even burnt.

J

------------------
"If the aquarium water has to be drunk don't waste the fish. In fact they'll probably be the easiest to eat even if you don't need the water. The cat is next in the pot." - John 'Lofty' Wiseman

Anthony
April 8th, 2001, 02:05 PM
We cannot tell you whether it detonated! You have to look at it and see, if there is no trace of the NaCLO3 plastique, a large crater and only tiny pieces of the casing left then it probably detonated. But it is extremely unlikely that it did because the blast would have been deafening.

The pop would have been the flash powder bursting the detonator casing.

JB
April 8th, 2001, 03:13 PM
Ok cheers, I'll try detonating it with acetone peroxide instead. It did look good though, heh. I usually get a terrific blast from ignition of the chlorate in metal containers, so I'll try it with a 'real' det. cap and let you know the results

PHILOU Zrealone
April 10th, 2001, 06:14 AM
NH4NO3/Al powder mix can be boosted up by nitroglycerin, nitroglycol, TNT, DNT, NM (always cap sensitive).
Alone, NH4NO3/Al mix is more sensitive than single AN... if the Al is very fine, it can be cap sensitive.Use very dry AN with some hydrophobic substance like an oil, stearate,...

------------------
"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"

Demolition
June 24th, 2001, 05:46 AM
I'm sorry to bring up such an old subject but it wouldn't be worth posting a new topic on what I have to say.

To see weather certain flash powders detonate couldn't you just place a small amount of flash on the ground and hit it with a hammer.It would ignite from the shock but if it ignited and went crack(such as AP)then wouldn't it suggest that the flash powder detonated???
Demolition

kingspaz
June 24th, 2001, 08:23 AM
i think flash could detonate if it was set off with a cap. it is similar to a chlorate/vaseline mix but with Al instead of vaseline. i don't think it could make the d-d transition though.

PHILOU Zrealone
June 25th, 2001, 08:22 AM
A sharp crack doesn't mean a detonation; it just mean a fast burning over 350m/s!!!1-2km/s is stil a deflagration! And it is hard to tell the difference between a deflagrating substance and a detonating one especially in the limit regio between 1.5 and 3 km/s.

------------------
"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"

Demolition
June 25th, 2001, 09:02 AM
That rules out my testing theory then.
Demolition

Demolition
June 27th, 2001, 09:55 AM
http://www.sonic.net/~brucel/videos.html
Download the car bomb video.They reckon that half a box full of M-80's can do that to a car,I think their having themselves on.Maybe someone slipped in a couple of sticks of Dynamite.http://theforum.virtualave.net/ubb/smilies/biggrin.gif
But if the test is true then maybe it can help out with the discussion.
Demolition

[This message has been edited by Demolition (edited June 27, 2001).]

DarkAngel
June 27th, 2001, 11:01 AM
I already saw that movie it's cool.

A bit of topic butt here is also a link on it to the Enschede (Holland) disaster those video's don't work for me but it's about a big firework warehouse in the middle of an neighbourhood that exploded and destroyed the whole place

and the other movie big bang is also awesome i need to dream about colored explosions soon!

------------------
DarkAngel

For explosives and stuff go to Section1 http://www.section1.f2s.com And http://run.to/section1 (http://www.run.to/section1)
sendtosection1@hotmail.com

TylerDurden
June 30th, 2001, 09:43 AM
The disaster with the fireworks company in Enschede is a good example of what flashpowder can do.
What happened was basicly that they had stored a lot of fireworks (filled with a flashpowder like mixture: I think perchlorate with titanium powder) and a fire caused one to go off and that one detonated the rest. These flashpowder bombs are mass-explosive when stored too close together. And they detonate.

Tony Montana
June 30th, 2001, 12:53 PM
Outsider:
When trying to detonate flashpowder, I would recommend using something else than flashpowder! Although a novel idea, and actually used/ C-4|RDX.
You sir, should stick to fireworks, and leave the real jobs to the real men, my opinion of you is low.

DarkAngel
June 30th, 2001, 08:04 PM
Last year when the Enschede disaster happend,you saw that a shockwave
destroyed all the roof tiles like it
whas moving water.
Pretty inpressive


------------------
ŠarkAngel

For explosives and stuff go to Section1 http://www.section1.f2s.com And http://run.to/section1 (http://www.run.to/section1)
sendtosection1@hotmail.com

Cricket
July 15th, 2001, 12:25 AM
In the exploding car video, it said "illegal fireworks", but not the active ingredients. So it could be flash or dynamite, no one knows that was even the box exploding in there. But is this whole thing really worth arguing about? I think we should concentrate or how to make it and new mixtures. Does it really matter if it detonate, yea, is it worth getting pissed off at people? I would just call the BATF and ask, but specify exactly what flash, if you are that worried about it. I would never use it as a filler anyway, just a detonator if I'm in a pinch.

Ericm115
August 21st, 2001, 03:30 PM
ok, I know nothing.. at all about this stuff. I may be totally mixed up, but to find out if it detonates or not, couldnt you use it as a detonator for something like ANFO, and light the flash powder. If it detonates the ANFO if would have to detonate right? Again, Im going on (probally mixed up) logic alone and just trying to contribute so please dont flame me.

Anthony
August 21st, 2001, 04:46 PM
No, that wouldn't prove it detonates as man secondary high explosives (i.e PETN) can be detonated with a hammer blow.

Fingerless
August 26th, 2001, 10:22 AM
LOL, I wonder how many people think that a few M-80's actually did that to the car? Misleading bastards....

<font face="Verdana, Arial" size="2">Originally posted by Cricket:
In the exploding car video, it said "illegal fireworks", but not the active ingredients. So it could be flash or dynamite, no one knows that was even the box exploding in there. But is this whole thing really worth arguing about? I think we should concentrate or how to make it and new mixtures. Does it really matter if it detonate, yea, is it worth getting pissed off at people? I would just call the BATF and ask, but specify exactly what flash, if you are that worried about it. I would never use it as a filler anyway, just a detonator if I'm in a pinch. </font>

mark
August 26th, 2001, 08:03 PM
I have no real scientific information, but explosions from impact are usualy louder than explosions from fuse. This is just my experience, though, and a very limited one at that.