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February 26, 2008
I'd love to get details on this:
A television documentary team said it had made a bomb by mixing a series of odourless and colourless chemicals that could be brought into an aircraft by passengers.
The liquids that were mixed to make the explosive cocktail were all contained in bottles of less than 100ml, which is the limit enforced at most airports around the world at present and was introduced shortly after British authorities thwarted an alleged attempt to blow up transatlantic aircraft in August 2006.
It blew a gaping hole in a decommissioned aircraft, snapping the ribs of the fuselage.
EDITED TO ADD (3/8): More info.
EDITED TO ADD (3/13): Here's the Channel 4 documentary. And this is well worth reading.
Posted on February 26, 2008 at 3:16 PM
• 66 Comments
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I also wold like to know the chemicals used and how they where mixed.
If you assume a fuel and an oxidizer I do not now of any truly oderless fuels that are comanly available.
Also I would like to know wher they put the resulting explosive and how to get the effect they claim.
To be blunt I think there is a lot they have not said that is not going to close the credibility gap.
So I am at best speculative untill a respected scientist conferms the "practical" not the "ideal" results. Just mixing in a bottle or cup is not close to lab let alone ideal standard.
I saw the documentary last night.
The guy was an explosives expert and didn't give details of the chemicals used. I can't recall him saying they were odourless but they were certainly clear and in 100ml bottles.
They were mixed together and placed near the inside skin of an old plane. The hole was pretty substantial.
Enough lies get published to support the 'war on terror' that I'm not going to believe a word of this unless the methodology is published and widely verified. Until that happens, the whole thing has about as much credibility as claims that Iraq had a nuclear weapons program.
It's easy to see that they left a lot of steps out in the report. Bad, irresponsible journalism. Sad, the general public will probably just accept it as fact, if only because they saw it the television. -d
Robert, Thanks for the link.
They didn't seem to show how it was detonated, but it looks to me like they probably used a stick of dynamite.
I find it interesting that the bottom half of the article ham-handedly pushes for passenger profiling, as if that has anything to do with the specific threat discussed in the first part.
I'm also interested in the mention of “a commercial detonator.��? That could mean that the actual threat scenario is more like “all you need are these easily available chemicals you can easily smuggle aboard – and this obviously dangerous piece of restricted electronics that you couldn't possibly get past even the dumbest airport screener on Earth.��?
This is not a software vulnerability. It cannot be fixed by patching the laws of chemistry and physics.
I agree that details should be made available and tested, but certainly not via the telegraph website.
The Iraq nuclear weapons program could be investigated without providing civilians the ability to construct nuclear weapons.
There is a major difference here.
I'd be curious - are there any norms for this sort of demonstration? How credible is it, without test data?
It's too bad the law requires you to use those clear, plastic bottles in your toiletry kit. It's too darn easy to confuse your bomb components with your aftershave.
Wait a minute:
"Researchers for Channel 4's Dispatches programme used a commercial detonator to explode their "bomb" at Lasham airfield, Hants."
Leaving aside issues relating to getting a detonator on-board undetected, what are they mixing on the plane that requires a detonator to set it off? The chemicals that have been discussed in the past result in highly-unstable compounds that go off if you give them a dirty look. They certainly don't need a "commercial detonator" to do their thing. If you can get a goddamn detonator on the plane, why not just bring a brick of C4 in a hollow book, or something?
I should think it would be easy to obtain expert corroboration of this demonstration if it is true. The size of the detonation suggests to me that if this really is possible that there are chemistry experts (to say nothing of demolitions experts) all over the world who would look at that explosion and say "Oh, right, that's an XYZ/ABC explosion."
I am not willing to trust a single televised demonstration of capability, although I perfectly willing to allow it to begin a dialog about such feasibility. Once the feasibility is agreed upon, then specific screening policies could be discussed - to leap from a single televised example to "...and so we should begin profiling" is a long enough jump that it starts to make me suspect the motives and therefore the authenticity of the demonstration itself.
The article notes, "You would need as few as five people...." Assuming the US limits (3 oz per bottle, all bottles in a 1 quart bag; not quite the European ones, but close), you can take less than 30 oz per person, in practice probably closer to 15. So they needed somewhere between 75 and 150 oz. I find that interesting.
Of course, it should be noted that you may need 5 people to get the liquid past security, but you only need 1 willing to die. The exact amount of liquid is irrelevant. Have the non-suicide bombers booked for other flights that leave near the time of the flight you're going to bomb. Discretely pass the components to the suicide bomber once you're past security. Under bathroom stalls would be the most obvious location. If you're worried about having too many people bumping into each other in this way, you can have people make lots of trips and do the transfers at layovers so the contact at any given airport is minimal, all within the secure area. With a bit of schedule juggling, some sort of collapsible container, and a lot of money for plane tickets, you should be able to get two or so gallons of liquid in a single container onto a plane with a single person.
Perhaps in the documentary the expert used a commercial detonator so that he could set it off remotely.
While it would make even more spectacular TV if the expert had set it off manually, perhaps by whacking it with a hammer, the expert might have declined to perform the experiment in that fashion.
Here's a patent on liquid explosives:
For those without the time to read it, it basically says high test hydrogen peroxide mixed with just about any flammable organic liquid in stoichiometric proportions can be used to make a mixture that will detonate.
The idea here is to produce a stable mixture, though, obviously optional for a terrorist.
Could be a weak and unpure version of Astrolite G. With ammonium nitrate dissolved in water and hydrazine as an acqueous solution. It'll be mostly water like. Hydrazine is particularly toxic and very corrosive. Both chemicals are somewhat unstable...
Anyone remember NBC's work on the Chevy Blazer?
I saw it too: before the segment on the explosive, they mentioned a test in which a lady smuggled the components of a detonator on to a plane, concealed in her underwear. A pat-down test failed to locate them, they said.
I thought that the general tone of the programme wasn't exactly supportive of the "war on terror", and critical of "security theater" (they used that term repeatedly). In short, I think the writers have been reading this site, since they avoided discredited ideas such as racial profiling or "more security". One interviewee described airport security as having deterrent effects, but the interviewer didn't seem convinced.
I trust this about as much as that famous US TV News program where they were demonstrating the explosive nature of Chevy truck fuel tanks and added fireworks to get the necessary visual effects.
Seems it's "factual" just like the "Brainiac" show. Kinda, sorta, like reality - but we stuffed few pounds of dynamite for dramatic effect...
While I understand their reluctance to publish the details, it should be examined by experts before actions are taken.
Assuming that this was the same old TATP fraud rehashed yet again, then the one thing they didn't say is that TATP was publicly debunked as a viable binary explosive in 2006. The Register got to the bottom of it here:
There are many effective ways to blow up an aircraft in flight. TATP smuggled as liquid is not one of them.
I rarely see debate (outside these circles) on the question of blowing up a plane compared to taking over a plane. Blowing up a plane is scary and tragic, and a moderately effective way of killing a moderate number of innocent victims, but it's not the only way to do that, nor the easiest, nor the most deadly. I don't want to be on board a plane with a bomb, but nor do I want to be in a long security line with one, or on a train with one or in a crowded mall, nightclub or any other packed collection of people.
We are especially afraid of planes being blown up. It's horrible, of course, and triggers our fear of a nasty death with factors beyond our control. Disable the plane and there is no way to survive. Very frightening. And in a self-referential way, we also would then shut down aviation if there were major fear of an attack, causing even more collateral problems.
But stopping a suicide bomber from finding a crowd is very hard, I would dare say impossible -- especially if we create crowds in inherently unscreened areas in the name of security. So as scary as plane bombs are, we have to question how crazy we should go in stopping them over other things.
Stopping people from using planes as weapons I understand.
We could move to developing more robust planes -- fly by wire aircraft with redundant data and power channels. Bomb resistant panels over central structural elements. Bombproof luggage containers in the hold. (These already exist.) Some cost of weight here, but affordable.
Secure cockpits and other measures are enough to stop people getting control of planes. Can we really stop suicide bombers?
I do not quite get this. If they need a *commercial* detonator why not just go with the plastic explosive C4? Then who cares about the hassle with the liquids at all? This bullsh!t is worse than the infamous "24" ...
So I end up thinking about the liquids ban every time I fly, and my latest thought is this: the metal detector (that you walk through) can't detect liquids. So if there really is such a thing as liquid bomb, all you have to do is carry it through on your person rather than putting it into your luggage. Just get a bunch of skinny terrorists wearing "fat suits" full of bomb juice underneath their oversized American clothes. Boom.
Alan - wrt: "With a bit of schedule juggling, some sort of collapsible container, and a lot of money for plane tickets [...]"
If all you're trying to do is get the non-bomber carriers through security - not actually onto the plane - you don't even need a lot of money for plane tickets. The bomber is the only one booked on the flight; he checks in online, screen-captures his printable boarding passes to an image file, makes four additional copies, and cut-n-pastes in each of the carriers' names.
It's not like TSA compares the boarding pass to a passenger manifest for any given flight - they're just checking that the name matches your ID and the date is correct...
Those darn Mexicans... They should all be sent back to Mexico. No exceptions.
The explosives demonstration was just one segment in an hour-long documentary which also drew attention to the fact that BAA, the company which runs most of Britain's major airports (including Heathrow), has failed to invest adequately in security screening.
BAA was acquired in 2006 by Ferrovial, which had to borrow around $20 billion to make the acquisition. Ferrovial now requires BAA to maximise income and minimise expenditure at Heathrow and its other airports in order to pay off the loan.
That's why the new Terminal 5 at Heathrow is effectively a shopping mall where you can also catch a plane. When it opens next month, we'll find out whether BAA have provided adequate security screening. My bet is that there will be long lines for security screening at Terminal 5, just as there are at the other terminals.
If all a terrorist wants to do is blow something up, the security waiting line is a far better target than any plane: more people, and you don't need any fancy plan to smuggle expolosives past security. How is this liquid bomb not a movie-plot threat? It's absurd.
I continue to be more afraid of the TSA than of any terrorist act involving airplanes.
@Len, re patent 3808062:
Actually you cannot mix hydrogen peroxide with "just about any flammable organic liquid" because they won't mix (like oil and water). The key idea of patent 3808062 is to use a sulfonic acid as the organic liquid. These are miscible with water, and hence also with aqueous hydrogen peroxide. Organic sulfonic acids (several are listed in the patent) tend to be odorless viscous liquids or odorless crystalline solids. Sulfonic acids are relatively easy to make and are also components of some detergents. I hate to say it, but this whole scenario could be realistic.
Not that this justifies the huge inconvenience of passenger screening. If a few airplanes get blown up occasionally, air travel will still be safer than going to the airport by car.
Well... hheeemmm, we won't have enough time to explain in this transmission, but I can repeat it with the FEAR VOICE and the FEAR MUSIC.
You see ? Any liquid and solids are dangerous. The TSA will soon forbidding people traveling by plane.
They used a standard detonator, though, which would be pretty difficult to get past a proper security check (not that one of those exists...)
One mix that is mentioned in the patent is H2O2 and methanol. Maybe you could even use high purity ethanol from the duty free so you have more room for oxidizer smuggling.
Furthermore, based on what is mentioned in that patent (interesting how several pages have been removed in the pdf) [b], maybe acetone and 90% H2O2 would blow up just fine with, maybe even without, a detonator. [/b] This puts a damper on the register's criticism about how hard it is to make TATP on a plane - if the H2O2 is concentrated enough, they could just mix and detonate. Maybe it would even get hot enough to go off by itself? In any case, detonators aren't too hard to make. I think you can use lead (shudder) azide, the primer in gun cartridges. Or a high energy spark, as from a shorted camera flash cap.
The bottle used in the demo is PET, which melts at 70 degrees and softens before that. So, presumably the liquids he's mixing don't produce a whole lot of heat when mixed. In the patent, it says most fuels do, but not the sulfonic acids mentioned.
I would think there are numerous other mixes it could be (another was mentioned in the comments), but it's hard to see anything could be easier to obtain than this.
The only problem is concentration of the H2O2.... maybe boil it off under low pressure? Or al queda's recipe with the starch?
I too watched this programme. The segment on the liquid explosive was quite convincing.
It did note that a commercial detonator was used, but added a caveat that a homebrew detonator smuggled aboard in components and assembled onboard, would also be viable. The explosives expert additionally noted that the liquid explosive would either produce a large explosion, or not go off at all -- there would be no "damp squib" partial detonation, to coin a phrase.
All in all, it looked like they'd done their research, and read this blog and the famous _Register_ article -- so they knew what to expect in terms of criticism, and dealt with it.
(By the way, I would reserve equal amounts of salt for anything printed at _The Register_...)
It's interesting that reports on this have mostly taken one of two tones:
"This is a detestable attempt at fear-mongering, and the attack isn't plausible"
"This is a detestable attempt to undermine the liquid ban, and the attack isn't plausible".
It can't be both, even if the attack isn't plausible. Personally I think it looks close, and attacks get better, not worse. I don't think that using a commercial detonator means that this technique (whatever it is) is negligible, regardless of whether you think the demonstration implies there should be more checks, or less.
Personally I think it should result in less checks - it looks as though we can't stop people mixing a liquid explosive on the ground airside of the security checks, and taking it onto a plane together with a detonator or the parts to make one.
We've all suspected that was the case, ever since the ban was introduced, especially if you assume that three or four attackers will co-operate to get the bits through separately. That being the case, there's no significant benefit in banning water from planes.
If the ban had been a temporary measure sufficient to prevent a specific known plot, where there was a concern that the plotters might have unidentified accomplices already prepared to carry out the same attack, then fair enough. But as a permanent security measure it sucks, and multiple demonstrations like this will eventually prove that it's also next to worthless.
@len - concentration of the H2O2:
You can get up to nearly 50% H2O2 by freezing the H2O2 solution; pure water ice crystallizes first, leaving the H2O2 in solution. Unfortunately (or perhaps fortunately ...), once the concentration is up to a little under 50%, a dihydrate of H2O2 will crystallize at about -50 degrees C.
People say that you can concentrate the solution further by heating it (water has a lower boiling point than H2O2), but I expect that to be a great deal more difficult than it sounds. H2O2 decomposes faster when you heat it, and if you try to distil off the water under reduced pressure (to keep the temperature down) that's a tricky technique. There are textbooks that explain how to do it, but it's a lot harder than just mixing solutions in the kitchen, especially when dealing with something like H2O2 that is not very stable anyway.
I have done both. Chilling is easy, you can get to ~60% or so before the ice contains the same amount of h2o2. Heating is pretty tricky. I kept getting thermal runaway.
Evaporation works really well. Got to +80% that way. But its not really all that stable at the level.
For 50%, well thats what i got from the store. 25kg was about 40euro.
I was under the assumption that the liquid ban was stupid because a bad guy could get explosive on the plane *anyway*. So we are no safer for a lot of inconvenience.
So what does this change? I already knew this could be done as does most chemistry majors.
You don't need explosives either. What about just starting a fire?
Personally I prefer shopping malls to security screening.
Pay attention, we ain't getting any real security with the security screening.
Why would a terrorist go to all the trouble to bring this crap on as a passenger when he can easily get a job as ground crew emptying the toilet for $7 per hour, put 200 pounds of something 'easy' to get, like ANFO; in a pressure wave generating/charge shaping container with extra shrapnel, in the cargo hold facing critical control structures like hydraulic lines and use whatever detonating mechanism he would like.
"If all a terrorist wants to do is blow something up, the security waiting line is a far better target than any plane: more people, and you don't need any fancy plan to smuggle expolosives past security. How is this liquid bomb not a movie-plot threat? It's absurd."
Ah, but are not the queues at the checkpoints are a direct manifestation of the fear of the population? Why would a terrorist attack his own handiwork?
But suppose we did start to see attacks from "Q Bombaz R Us(TM)". It's not impossible that the authorities would quickly dispense with choke-points like this and begin to implement stuff that would make the job of the Big Bad T more difficult. So I think it would probably make more sense to continue to penetrate the seive and blow stuff up on the inside of the perimeter, and to defer attacking the surface until you have little other choice.
At least that is what I tell myself (as well as recalling the extreme rarity of any kind of attack) as I stand in line, awaiting the Official Indignity, and practicing the smile you must wear while enduring it.
"Personally I prefer shopping malls to security screening."
Suppose instead of paying them for their current "work", we send the entire TSA work-force to university. Upon graduation we fire them so they can get either get or create better paying, more valuable jobs.
Question: would we be wealthier in the end doing this, even factoring in whatever extra losses because they weren't removing water bottles from airplane passengers?
After going though LAX, it clear that the only requirement for employment is that you can't speak English.
We were even ushered into a restricted area, at which point slightly more "official" looking personal starting getting very angry with the ushering! We almost had to get re screened.
And how many people are employed at LAX. It would be easy to get one through. Get a bigger enough group of sleepers to get critical jobs in infrastructure.
@Alan De Smet - ah ha!
That scenario explains why the cops are hiding out in washrooms looking for people signaling from stalls! The whole gay sex thing was for plausible deniability.
@Anonymous: interesting concept, but I dont think it would work - the average person I have seen as a screener would have had a diffcult time graduating high school; my late shetland sheepdog would probably do better in college (maybe not after he died). He'd almost certainly make a better screener. And he (was) definitely friendlier, cuter and more polite.
Ok, from my US Army experience, I would think that means a blasting cap. Now, that was a while ago, but it seems to me that an electric cap would be fairly easy to smuggle onto a plane either on your person or in your carryon.
They're also somewhat easy to detonate (I suspect a modified iPod would have enough juice).
So... that part is possible... however unlikely.
"Under bathroom stalls would be the most obvious location."
Thanks to Freedom-loving Senator Larry Craig, Minneapolis will not be a party to such perfidy.
how are you all complaining they didn't list out each chemical and how to do it? That would have been reckless! Hey terrorists, here's a way around our security measures, now hurry hurry!
Security must be realistic at times and cost effective.
Terrorists probably go for the low hanging fruit.
Plane security has reduced a lot of the low hanging fruit, 80 20 rule. Life.
Smoke and mirrors has been the game of congess / government for a while. They and others in the USA are the biggest threat to us all.
We have all been had, and its getting worse. Oh well. I love my country, but I fear the powers more than the terrorists.
I watched the entire program. The explosive was just a hook to hang the actual story - airport security is mostly theatre and what security is in place is trivially worked around.
The second part of the program pointed out that the huge delays at Heathrow and other BAA airports are not down to the new security measures. Other non-BAA airports, such as Luton, restored order and reduced airport transit time to roughly the same as before the "binary liquid explosive" panic.
It was suggested that BAA are taking advantage of "security" to increase airport transit time and hence maximise the income from airport shops.
Don't get too worked up about the practicality of the binary liquid explosives. If you can get them past security, you can get other stuff through that could cause casualties.
None of this is new to anybody who reads this blog. If fact, Andrew, if you are lurking, give Bruce a mention next time :-)
Anyone seen the film 'Kenny' and what happened to the side of the portaloo? I think they are just using a really strong curry, though that does involve some powder it could be 'smuggled' onboard as a paste ...
High test peroxide? Where are you going to mix it, in the sink of the lav?
What bottle are you going to carry it in? I suggest polystyrene for all you proto-terrorists out there. Of course, I suggest that proto-terrorists try to make nitrogylcerin and TATP as well, makes them easy to find.
Anything involving smuggling and mixing 50% and greater concentrations of H2O2 in non passivated containers is a non threat to the airplane.
The art of explosive mixtures is to make a mix that is safe to carry, *and mix*, and then, after that reaction completes -- but not before -- is able to be detonated. Almost anything involving H202 and a wet metal or plastic sink fails that test badly.
If you require a lab to be setup in the plane, it is not a threat.
I am always perplexed that the security mechanisms in place seem to deal with very short term immediate threats - it only takes two minutes to go through airport screening (that is once you have finished queuing) and that is where all the focus is.
The dedicated terrorist is prepared to establish his attack over a very much longer period of time.
Remember the first attack on the world trade centre was the bomb in 1993. It took them a further 8 years to prepare and complete that job.
In that kind of time frame, you could have an entire team working for you in an airport, in security and even airside shops (do they really check all the goods coming into airport shops?)
@Erik V. Olson
Having worked with 50% h2o2 a lot I can tell you its quite stable. Any clean plastic container is fine. Even quite dirty ones only result in a bit of bubbling. Metal containers need passivation.
The level of stabilizer can affect the chemistry quite a bit however.
You can mix quite a lot of organics (like CH3OH) to levels where they will detonate but are stable.
I saw the broadcast and it seemed to be an odd documentary encompassing a number of disparate airport related issues not just security.
The liquid explosive bit seemed on the surface to be pure tabloid-bait but did expose the security theatre nature of the rules on carrying liquids and the arbitrariness of the 100ml per container limit. It was set off using a commercial detonator purely for reasons of safety I would imagine as Dr Sidney Alford did mention that the explosive could be set off by an amateur using simple ignition methods.
But also mentioned by Philip Baum in the documentary was that in a test of 24 airports carried out for a government that personnel at every single one failed to detect bomb components carried by a woman through the security gates. So perhaps smuggling through a commercial detonator wouldn't be out of the question in any case.
Yep, and my cursory knowledge of inorganic chemistry (and a couple of national prizes in chemistry scholarship competitions) say that some dynamite was very helpful in producing the dramatic effect.
I find it very amusing that apparently sane and intelligent people would believe anything they say or show on TV.
I can tell you that I could do that demonstration without any "dynamite". I don't need to believe the TV when i have my own experience to go by.
Have you ever done some real demolision work or seen real explosives? (high speed ones, not Hollywood flame wonders)
Secure cockpits and other measures are enough to stop people getting control of planes. Can we really stop suicide bombers?
Posted by: Brad Templeton at February 26, 2008 08:39 PM
Here is my question; why have any way to get from the cabin to the cockpit? Why not have a separate boarding entrance for the cockpit crew, and everybody else boards the regular way? How many times do the cockpit and cabin crew need face to face communication during a flight?
Fact is that we don't need to do anything. We are already safe enough. Its far far greater risk to drive than fly. And even then you are far more likely to die from a "normal" plan crash than a attack.
How many flights since 11/9 ? how many deaths from flying? from Terrorists?
The 100 ml limit on the amount of a single "bottle" of liquid has nothing to do with security, it is about MONEY.
Scenario: Leave home to catch international flight from London to New Zealand. Oh forgot my toilet gear. Call into local supermarket. 250 ml Toothpaste $12.00, 300 ml Deodorant $15.00, 250 ml Shampoo $8.00. Total $35.00. Good on our way
Arrive at London airport -- can't take that liquid?? Throw away
Get into shopping mall inside security.
Can now buy toilet gear again: 250 ml Toothpaste $22.00, 300 ml Deodorant $35.00, 250 ml Shampoo $18.00. Total $75.00
Now fly to Sydney (stop over on way to NZ). Catch plane to NZ -- can't take that liquid?? Even though you have reciepts from London Duty Free.
What has that go to do with Security?
There have been two pieces missing from the public discussion, and I have been reluctant to post them. You said you wanted the details, so here is what I think the pieces are:
The first finally came out in the comments above, so it is no longer so missing: use a deflagrating mixture of 90% H2O2 (made by fractional crystallization of grocery store 3% solution, done in your home freezer) and a clear liquid reducing agent (an alcohol, for instance). It's a simple mixture and needs no fancy lab in the air, makes no fumes, and so on. High school chemistry teaches how to calculate the correct proportions.
The dodgy issue there is stability for handling. One post asserts experience with a substantial fraction of methyl alcohol in concentrated H2O2, and claims that it is stable enough to handle. (I had first thought of using glycerine.) So maybe you can even mix on the ground, and only have to pool the small bottles in the air. I routinely carry an empty large bottle through the screening station to fill with drinking water once I'm inside. Of course a baggie would do for a container if it had to. The essential requirement is an inert inner surface, like polyethylene or polypropylene.
The second missing piece is to avoid needing a blasting cap. One way would be to make a catalytic initiator instead of a shock initiator that you have to buy from a suspicious vendor and that would have a recognizable shape. To do that, put a small portion of the explosive mixture in a confining structure (may be needed to make the deflagration turn into a detonation - I have not done the experiment to see), then to set it off introduce a vigorous catalyst for decomposition of peroxide. Manganese dioxide has been used for that purpose to decompose H2O2 fuel in spacecraft thrustors. That is the black stuff in all 1.5V alkaline cells and in all 3V (as opposed to the less common 3.6V) lithium primary cells.
Another possibility is a cartridge primer from a suppler of reloading supplies. That would also be expected to light off the confined material, and is designed to provide the seal you would need to complete the confinement. Dent the outer surface to set it off. Again the blast from the confined stuff breaking out through a deliberately weak side and into the rest of the mixture sets the rest off.
Actually, my reticence to post is probably silly. As with nuclear weapons, the crucial secret is that it really can be done. Here the scale of expertise needed to go from that assurance to a working bomb is pretty small, and as we are learning, engineers are over-represented among terrorists. Still, we probably don't want eager high school kids playing with this stuff.
Fractional crystallization in general won't get much above IIRC 67% h2o2. At this point the newly formed ice will have the same concentration of h2o2. Also you going to need a *HUGE* amount of 3% h2o2 to get there as there will always be a little h2o2 in the ice even at low concentrations.
As for the disclosure comments, there is no security gained by keeping this sort of thing secret.
I was a high school kid who did this stuff. It was a lot of work and study, and I was safe.
Idiots will hurt them selfs lighting BBQs with gasoline and do not need to be protected from there own stupidity.
Has anyone ever heard of the "Bojinka" plot that was carried out my the first attacker on the WTC, Ramzi Yusuf and his uncle Khalid Shaikh Mohammed?
He was able to construct a liquid bomb on a flight and set it with a timer from a modified Casio watch. He was able to go the the lavatory on the jet, construct the bomb, put it back in his small travel bag. He then went back to a seat above what he thought was the position of the fuel tank. The only thing that saved the passengers on the jet when the explosive was that I believe it was a 747 and not a 727, where the bomb would have made contact with the fuel tank. Being it was a different series of jet, it missed the fuel tank but was not a lucky flight for one passenger, Haruki Ikegami, a Japanese businessman who was sitting in the seat where Ramzi Yousef planted the bomb.
The arrangement claimed by patent 6780206 looks too demanding for ad-hoc use, but one could replace it with a classic refinery cascade as used in the Oak Ridge isotope separation plant. The text says there is a 2% difference in H2O2 concentration between ice and melt (conditions unspecified...), and that would be enough to make a reasonable sized cascade work - a few dozen stages fed by 3% stock. The cascade could take the form of bottles arranged at least conceptually in a line in order of concentration. All the bottles get half frozen, then the liquid from each is poured off into a bottle one place down, the ice is melted and goes one place up and joins the liquid poured off from one place higher yet to freeze again. Once the concentrations stabilize, the ice from the top bottle is your product from each freezing cycle, and the liquid poured off the bottom is discarded. Our putative bomber could measure density to see how well he was doing and to get the number of bottles and feed point right.
I think we have to assume that a pretty ordinary chemist could make H2O2 to specification without leaving tracks if he bought his 3% peroxide cautiously. And taken together with the rest of this thread I think that means that a) liquid bombs are a real possibility and b) current or likely airport precautions against them could be evaded.
BTW, I also played with deflagrating mixtures in high school and learned a lot of chemistry. I thought I was being careful and indeed got away with it, but did have one very close call. What I was using was lots better behaved than concentrated peroxide.
A less careful acquaintance got killed in an unrelated incident. I do worry about high school kids, even ones just like I was.
According to my manuals, purchased from the U.S. Government, consider these two:
PLX (Picatinny Liquid eXplosive)
The last, when properly made (seldom is) is 50% more potent than C-4. 100 ml of either will do some serious damage.
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