C4

Composition-4, often shortened to "C-4", is a common variety of military plastic explosive.

The term composition is used for any stable explosive, and "Composition A" and "Composition B" are other known variants. Composition-4 is 1.34 times as explosive as trinitrotoluene, which is more known as "TNT". It has gained public notoriety due to exposure in media including films and video games.

C-4 is made up of explosive, plastic binder, plasticizer and, usually, marker or taggant chemicals such as 2,3-dimethyl-2,3-dinitrobutane (DMDNB) to help detect the explosive and identify its source.

As with many plastic explosives, the explosive material in C-4 is RDX (cyclonite or cyclotrimethylene trinitramine) which makes up around 91% of the C-4 by weight. The plasticizer is diethylhexyl or dioctyl sebacate (5.3%) and the binder usually is polyisobutylene (2.1%). Another plasticizer used is dioctyl adipate (DOA). A small amount of SAE 10 non-detergent motor oil (1.6%) is also added. C-4 detonates with a pressure wave of about 8,040 meters per second (26,400 ft/s) equaling 28,900 km/h (18,000 mph).

C-4 is manufactured by combining RDX slurry with binder dissolved in a solvent. The solvent is then evaporated and the mixture dried and filtered. The final material is an off-white solid with a feel similar to modeling clay.