Question for people trained in explosives

[miguelencanarias]

Lacking any understanding of how these things work, let me ask you a couple of (probably very stupid) questions:

If movies are to be believed, you arm a plastic bomb simply by inserting a detonator in the plastic brick.

My first question is: wouldn't I disarm the bomb simply by removing the detonator from the plastic?
My second question is: if for some reason you cannot remove the detonator, couldn't you reduce the explosion simply by cutting off the explosive around the detonator?

As I said, I don't have the faintest idea of how these things work, it is just that my common sense cannot accept the Hollywood image of a bad guy driving a detonator inside a plastic explosive, followed a scene later by a good guy sweating with some pliers in his hand, wondering if he should cut the red wire or the blue wire. It just doesn't seem right.

[JUNKHO]

I am not trained in it - but here is some info:



Just as with other explosives, you need to apply some energy to C-4 to kick off the chemical reaction. Because of the stabilizer elements, it takes a considerable shock to set off this reaction; lighting the C-4 with a match will just make it burn slowly, like a piece of wood (in Vietnam, soldiers actually burned C-4 as an improvised cooking fire). Even shooting the explosive with a rifle won't trigger the reaction. Only a detonator, or blasting cap will do the job properly.

More at:
http://science.howstuffworks.com/c-42.htm

and this:
http://en.wikipedia.org/wiki/C-4_%28explosive%29

[Othree52]

My first question is: wouldn't I disarm the bomb simply by removing the detonator from the plastic?

Yes. 1234567890

[KillerBD]

You must have watched the movie Hurt Locker... Many of the same logical questions popped into my head as well... Kinda like the guy with the bomb vest pad-locked onto him... Why the **** didn't they just remove the detonator/timer controlling the bombs? I guess it just makes for a better theatrical show to have some Mcguyver like fellow trying his damndest to remove it like some dumb cave-man with bolt cutters rather than use his brain...

[MadOnionSix]

#1 with an electrical detonator the wires would have to be long enough so that the detonator isn't close to the explosives, a pyrotechnical detonator would have to be even further away from the explosives. If I made a " bomb " they would be veeeeeeeeeeeery short !

#2 yes, but be careful for static sparks

I would love to see this on Mythbusters :lol:

[flanker7]

let me ask you a couple of (probably very stupid)

As a person who has trained in explosives I can tell you this, if you have a question about explosives ASK it! :-)

The answer to your questions is yes, but there are varius methods of ****ytraping(only imagination is the limit) an explosive device and maybe the apparent solution to disarming it is just a trap. For example, by pulling the obvius detonator out you close a cirquit which triggers a hidden detonator

[highdiver_2000]

Cutting off one detonator, might trigger off another. Pulling them out might work. You still need a decent air gap to the charge. I may be talking out of my ass.

[pekka elo]

You must have watched the movie Hurt Locker... Many of the same logical questions popped into my head as well... Kinda like the guy with the bomb vest pad-locked onto him... Why the **** didn't they just remove the detonator/timer controlling the bombs? I guess it just makes for a better theatrical show to have some Mcguyver like fellow trying his damndest to remove it like some dumb cave-man with bolt cutters rather than use his brain...

Man, I was thinking exactly the same although my knowledge of explosives is limited to making simple charges with pyrotechnic fuzes. One of the many reasons I hated the film.

On the matter of cutting a wire causing another detonator to explode, I don't think it's so easy to rig. Seeing as an electric detonator explodes with a tiny current, there can't realisically be any "carrier" current in it to sense if it's cut off, can there? If there's no current in the wires, it's an open circuit and can be cut off, no matter if it's the red or black wire.
Any combat engineers here to know better?

[Marsuitor]

An electric detonator works much the same way as a lightbulb. Only instead of a vacuum inside a glass casing you (mostly, if you're not using NPED-detonators that is) have primary explosives inside a metal casing. Power added to the circuit will cause the thin filament inside the detonator to generate enough heat to cause a detonation in the primary explosives (usually around 0.2g leadazide and 0.8g tetryl). This is the start of the explosive chain.
It goes without saying that removing the detonator entirely will sever the contact with the secondary explosives (in your example a block of plastic explosives). Cutting wires removes the power source from the setup, and could render the object safe enough for moving, but you still need to remove the detonator(s) for it to be considered proper safe, as well as some other factors that usually come to play.
What people are referring to when talking about "cutting the red or blue wire" would most likely be what's called a collapsing circuit. That is, if circuit A is broken, then this would cause circuit B to complete, power added, and thus setting the charge off. Said in simple terms...

Hurt Locker is an atrocious piece of shyt film with so many failures in logic and common military sense in a big part because 1) it wouldn't be interesting enough for the general audience if it were to be realistic (a real life IED case can take many, many hours to solve) and 2) it's not possible to make a film like this realistic due to the fact that showing real-world RSPs and our TTPs on IEDs would give the badguys a very good idea of how to make their IEDs more effective in the future.
Result? Alot of people buy what they see in this film as "realistic", while the folks who deal with this stuff for real writes it off as total cack.

Guy pulls the detcord to reveal many daisy-chained artillery shells. Instead of cutting each and every branch as he does in the film, why not just cut the main cord leading off somewhere else to the initiation point? First that is, so you've atleast severed the portion of the IED between main charge and triggerman before you start working on rendering the rest of the IED safe. Just saying...:roll:

[miguelencanarias]

Fun fact: no, I haven't seen The Hurt Locker, but I ordered it via amazon.co.uk a couple of days ago and now reading you guys I feel I have wasted my money, and I haven't received it yet. That will teach me to make questions...

[highdiver_2000]

On a related topic, the initiator for the car air bag has a trickle current. If for some reason the circuit broken, bad wire or initiator the air bag light on the dash will turn on. To blow the air bag a higher current is pumped.

[Pandemonium]

Fun fact: no, I haven't seen The Hurt Locker, but I ordered it via amazon.co.uk a couple of days ago and now reading you guys I feel I have wasted my money, and I haven't received it yet. That will teach me to make questions...

just make sure you're slightly wasted, so you can't think to much, and you might enjoy the movie.

I have just one question, are pyrotechnical detonators still commonly used for IED's?

[miguelencanarias]

just make sure you're slightly wasted, so you can't think to much, and you might enjoy the movie.

I am a teetotaler, so basically I am pretty much fvcked now.

[flanker7]

Take a good look at your new camo and then watch the movie! It can't be worse...

:-) just jocking man...

[miguelencanarias]

Take a good look at your new camo and then watch the movie! It can't be worse...

You owe me for a keyboard ruined by spilled coffee. Good one!

[Marsuitor]

I have just one question, are pyrotechnical detonators still commonly used for IED's?
If in pyrotechnical you mean standard older type detonators with a gunpowder fuse stuck in it then no, most of the stuff the badguys use is electric in some form or the other (due to quite obvious issues in timing a gunpowder fuse correctly vs. using instant electricity, esp if using a command-wire). We call these mechanical detonators btw, so it could be i'm thinking of something else from you here.
If you're thinking of those CAD/PAD-type units commonly found around pyrotechnics on fighter jets and helicopters (flare launchers, charges on bomb-lugs to seperate these from hard-points, ejection seats etc.) then i wouldn't really know - i haven't heard of it atleast. These, in most cases, have an internal composition that would present certain obstacles for a would-be terrorist to overcome to make them set off an IED correctly.

[LineDoggie]

http://i65.photobucket.com/albums/h222/linedoggie/cs_349.jpg Just remember to watch out for Mister Squirrel........

[miguelencanarias]

Linedoggie, I don't follow...

[tommyflatline]

Linedoggie, I don't follow...


its a classic u.s. movie called caddyshack. the guy in the picture is holding a plastic explosive shaped like a squirrel...somehow the real squirrel (a puppet) knows its an explosive..i wont spoil the rest of the movie.

[miguelencanarias]

Coming to think about IEDs, specifically those activated by a cellphone call, how difficult would it be to use signal inhibitors so cellphones don't work in the proximity of a convoy? Didn't the Brits use something like that during The Troubles in Northern Ireland?

[dangerdan87]

We came across 3 155 shells that were laid inside a wall of a house rigged to blow...we neutralized the explosives with a JDAM - it worked like a charm and 1 less building to search later.

[Beowulf]

We came across 3 155 shells that were laid inside a wall of a house rigged to blow...we neutralized the explosives with a JDAM - it worked like a charm and 1 less building to search later.

Interesting, we had a similar discovery, weapons cache in the walls of a house in the korengal. We were foot mobile so...we just reduced the house.

worked really well.

[Connaught Ranger]

Coming to think about IEDs, specifically those activated by a cellphone call, how difficult would it be to use signal inhibitors so cellphones don't work in the proximity of a convoy? Didn't the Brits use something like that during The Troubles in Northern Ireland?

As I recall, the B.A. developed a computer system capable of randomly ringing mobile phone numbers which in turn had the effect of detonating devices, so tough sh*t if you were a P.I.R.A. techie just completing setting up a live bomb, the ding a ling was probably the last sound you heard before going out with a bang.

[martinexsquaddie]

also had ecm gear allegedly could interfear with heart pacemakers would certainly mess up TV signals
important cup final footy match time to do a mobile patrol near popular pira pubs oops

hurt locker I want my £4 on demand back

[miguelencanarias]

hurt locker I want my £4 on demand back

Oooooooh shiiiiiiiiit....

[miguelencanarias]

mobile patrol near popular pira pubs oops

I gather pira means pro-IRA?

And you messed with their TV reception during a football match? A FOOTBALL MATCH? Is there no decency in this world?? There are a few things sacred in this world and protected by the Geneva Convention, and football is one of them!! LOL

[Connaught Ranger]

I gather pira means pro-IRA?

And you messed with their TV reception during a football match? A FOOTBALL MATCH? Is there no decency in this world?? There are a few things sacred in this world and protected by the Geneva Convention, and football is one of them!! LOL

G.A.A. All Ireland Finals of Irish Football & Hurling!

[miguelencanarias]

ROFL

That's mean, man. It's mean.

[junglejim]

I gather pira means pro-IRA?




I think they get paid more and get RAP video deals

[flanker7]

I gather pira means pro-IRA?


It means Provisional(spelling?) IRA if I remember correctly

[panzerwerk]

Just finished reading "Eight Lives Down" By Maj Chris Hunter , he was British EOD in Iraq and talks in detail about everything being asked here , it was a great read , I recommend it , he also touches on Northern Ireland and work he did in South America , would have been a better movie then Hurt Locker although I enjoyed Hurt Locker , it was not for realism , I enjoyed as I did Star Wars or Lord of the rings .

[Corrupt]

Just finished reading "Eight Lives Down" By Maj Chris Hunter , he was British EOD in Iraq and talks in detail about everything being asked here , it was a great read , I recommend it , he also touches on Northern Ireland and work he did in South America , would have been a better movie then Hurt Locker although I enjoyed Hurt Locker , it was not for realism , I enjoyed as I did Star Wars or Lord of the rings .


Eight Lives Down was an epic book!!


It means Provisional(spelling?) IRA if I remember correctly
Aye Provisional IRA, who took over from the IRA when they declared a ceasefire in 74
Then the RIRA (real IRA) formed when PIRA declared a ceasefire in 97
Then the CIRA (Continuity IRA) When RIRA declared a ceasefire in 98

[BMF_EOD]

A lot of crap in this thread that may just get you killed. Call the pros and they will deal with it. Combat Engineers are the equivalent of a paramedic- might save your life but do you want them doing your heart surgery? EOD Techs are the surgeons of the explosive world. Choose wisely, no disrespect intended.


We play the game everyday for real and win often...... but sometimes loose seasoned operators to seasoned bad guys. The game is far more interesting and dangerous than any movie can make it. If you can think of an a tricky move, I guarantee the enemy already has.... The obvious is never what it seems. Routine is deadly.
http://www.youtube.com/watch?v=JfXRXNakvl8

[digrar]

On that note, I think this has run its course, those who know aren't going to be telling stories on a forum, knowledge is power in this game.