from..http://news.softpedia.com/news/How-C-4-C4-Explosive-Works-51224.shtml

How C-4 (C4) Explosive Works


Adjust text size:

April 4th, 2007, 14:52 GMT| By Lucian Dorneanu

Terrorist C4 pack from the game
Enlarge picture
Twenty years ago, most people didn't have any idea what C-4 was. Recently, it has become an all-too-familiar term, popping up in newspapers and on television all the time.

C-4, is one of the many varieties of plastic explosives. The basic functioning principle of all plastic explosives, also called plastic bonded explosives (PBX), is to combine explosive chemicals with a plastic binder material, which fulfills two major roles. It coats the explosive material, so it becomes less sensitive to shock and heat, and that is what makes it relatively safe to handle the explosive, and it makes the explosive material highly malleable, so that you can mold it into different shapes to change the direction of the explosion.

The explosive material in C-4 is cyclotrimethylene-trinitramine (C3H6N6O6), commonly called RDX (which stands for "royal demolition explosive"
or "research development explosive"). The additive material is made up of polyisobutylene, the binder, and di(2-ethylhexyl) sebacate, the plasticizer (the element that makes the material malleable). It also contains a small amount of motor oil and some 2, 3-dimethyl-2, 3-dinitrobutane (DMDNB), which functions as a chemical marker for security forces.

To make C-4 blocks, explosives manufacturers take RDX in powder form and mix it with water to form slurry. They then add the binder material, dissolved in a solvent, and mix the materials with an agitator. They remove the solvent through distillation, and remove the water through drying and filtering. The result is a relatively stable, solid explosive with a consistency similar to modeling clay.

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.

A detonator is just a smaller explosive that's relatively easy to set off. An electrical detonator, for example, uses a brief charge to set off a small amount of explosive material. When somebody triggers the detonator (by transmitting the charge through the detonator cord to a blasting cap, for example), the explosion applies a powerful shock that triggers the C-4 explosive material.

When the chemical reaction begins, the C-4 decomposes to release a variety of gases (notably, nitrogen and carbon oxides). The gases initially expand at about 26,400 feet per second (8,050 meters per second), applying a huge amount of force to everything in the surrounding area.

At this expansion rate, it is totally impossible to outrun the explosion like they do in dozens of action movies.

To the observer, the explosion is nearly instantaneous - one second, everything's normal, and the next it's totally destroyed.

Less than a pound of C-4 could potentially kill several people, and several military issued M112 blocks of C-4, weighing about 1.25 pounds (half a kilogram) each, could potentially demolish a truck.

Because of its stability and sheer destructive power, C-4 has attracted the attention of terrorists and guerilla fighters all over the world, and as long as it is readily accessible, C-4 will continue to be a primary weapon in the terrorist arsenal.
Copyright © 2001-2010 Softpedia. Contact/Tip us at

TAGS:
explosive | counterstrike | demolition | detonation
Read by 7,405 user(s) | Link to this article