Question about plastic explosives

[Alone]

I'm hoping this is just a movie thing.

Every movie I see with plastic explosives involved as a trap or a planted bomb seems to involve a couple people sitting around trying to figure out how to disable it. They're always cutting wires and crap, but my question is simple:

...why don't they just pull the blasting caps out?

 

[Jeeebus]

...why don't they just pull the blasting caps out?

The red cap or the blue cap?

 

[Powermoloch]

The red cap or the blue cap?

What if you're color blind !?

 

[BoomerD]

If it was only that simple...

Obviously, for the sake of movies, they MAKE it look that easy, but in reality, disarming plastique is much more difficult...you might have to not only remove the blasting cap, but.......cut the wires as well. (to prevent the primer from going off)

Dangerous bizness...do NOT try this at home.

 

[Alone]

If it was only that simple...

Obviously, for the sake of movies, they MAKE it look that easy, but in reality, disarming plastique is much more difficult...you might have to not only remove the blasting cap, but.......cut the wires as well. (to prevent the primer from going off)

Dangerous bizness...do NOT try this at home.

Why not remove the blasting caps from the explosives and then cut them off? I really don't understand how this could be any more complicated.

 

[Glitchny]

Why not remove the blasting caps from the explosives and then cut them off? I really don't understand how this could be any more complicated.

I imagine there is a way to make the bomb somewhat more complicated to disarm than just unplugging it.

What if you're color blind !?

You pull them all!

 

[Alone]

I imagine there is a way to make the bomb somewhat more complicated to disarm than just unplugging it.

That's why I'm asking. Removing the charges from the explosive can't cause anything to detonate. So assuming they're exposed...what complications could there be?

 

[BoomerD]

Because it makes movies and television more exciting...

Why the fuck to the geeks here always try to overthink simple shit?

If it was as simple as removing the blasting cap, (detonator) then cutting the wires to the detonator to prevent it from being detonated...movies would have less drama...

Hell, C-4 is pretty damned stable. We used to cut off small pieces and burn it to heat our C-rations...but you had to be careful...burning C-4 puts off poisonous fumes...and can make you sick as hell....or dead.

 

[DrPizza]

If you have multiple charges, then you could create a circuit such that any change in resistance or capacitance results in all the blasting caps being triggered. (or, all but one.)

 

[Alone]

That's mostly what I expected. Just wanted to make sure I wasn't missing anything critically important in case I ever have to disarm a bomb.

If you have multiple charges, then you could create a circuit such that any change in resistance or capacitance results in all the blasting caps being triggered. (or, all but one.)

If you pulled them all out first you wouldn't have any change in resistance.

 

[lxskllr]

Motion sensors can be easily field improvised also. Pulling a blasting cap could set it off. There's a lot of reasons outside of plot devices that make bomb disarming more difficult than it initially appears.

 

[BoomerD]

Motion sensors can be easily field improvised also. Pulling a blasting cap could set it off. There's a lot of reasons outside of plot devices that make bomb disarming more difficult than it initially appears.

Yes, sophisticated bombs can indeed be built with lots of "fail-safes," traps, and triggers that make disarming them VERY difficult...but from the way the OP was written, it sounded like he was just talking about simple explosive devices.

Truly sophisticated devices can have proximity fuses, motion-sensing fuses, temperature-change fuses, resistance-sensing fuses, and many other things...all designed to prevent someone from tampering with the device with the intent of disarming it.

OP, just watch the damned movie and enjoy it...just pretend that everything you see makes sense...or is truly realistic. It's easier that way.

 

[lxskllr]

OP, just watch the damned movie and enjoy it...just pretend that everything you see makes sense...or is truly realistic. It's easier that way.

^^^
Best advice. I don't watch a lot of video, so I wasn't sure where the OP was coming from. I see a lot of people bitch about stuff, especially in the science fiction genre, but I seldom have a problem with it. It's supposed to be entertainment. It's best to just shut your brain down, and be entertained. The only inaccuracies that bother me are chronological problems, eg music from the wrong period, items from the wrong time, etc. That's rare seeing things blown that badly.

 

[Alone]

I don't recall bitching about anything. I asked a question and got my answer:

Yes, sophisticated bombs can indeed be built with lots of "fail-safes," traps, and triggers that make disarming them VERY difficult...but from the way the OP was written, it sounded like he was just talking about simple explosive devices.

Truly sophisticated devices can have proximity fuses, motion-sensing fuses, temperature-change fuses, resistance-sensing fuses, and many other things...all designed to prevent someone from tampering with the device with the intent of disarming it.

 

[DrPizza]

If you pulled them all out first you wouldn't have any change in resistance.

The plastic explosive itself could be used as a portion of the circuit once the detonators were inserted. I haven't a clue what the resistivity of C-4 is, but consider a wire on the detonator, and a 2nd wire embedded in the plastic explosive. i.e. consider the C-4 itself to be a resistor. Once the detonator were even half pulled out, I'd think that the change in resistance would be sufficient to trigger the detonator being set off. If you google it, I'm sure there's no shortage of circuits where some alarm is triggered by a slight change in resistance of some component.

 

[sandorski]

Plastic=Oil=Supporting Terrorists

 

[DrPizza]

Plastic=Oil=Supporting Terrorists

But C4 is made by the nitration of hexamethylenetetramine (sp?). Hexamethylenetetramine and hexamethylenediamine are complexes formed by the dehydration of ammonia and formaldehyde. No oil there!

edit: ooops, that makes RDX or T4; C4 is made from RDX

 

[Jaepheth]

What I don't understand is why they, the bomber(s), don't just put the bomb in a pressurized, opaque box with a barometer trigger, a light sensor trigger, and an accelerometer trigger.

Or just set it to detonate when the timer reads 1 hr remaining.

 

[sandorski]

But C4 is made by the nitration of hexamethylenetetramine (sp?). Hexamethylenetetramine and hexamethylenediamine are complexes formed by the dehydration of ammonia and formaldehyde. No oil there!

edit: ooops, that makes RDX or T4; C4 is made from RDX

Details details...

 

[SMOGZINN]

I don't know, all I know is that if I ever become a villain I’m going to have all my bombs go off when the large digital countdown hits 1:00 instead of zero, that way I catch the hero mid-speech while his procrastinating ass is still hem-hawing over which color wire to cut.

 

[SooperDave]

http://en.wikipedia.org/wiki/Harvey%27s_Resort_Hotel_bombing