C-4 or Composition 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. C-4 is 1.34 times as explosive as trinitrotoluene (TNT).
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 (also known as cyclonite or cyclotrimethylene trinitramine) which makes up around 91% of the C-4 by weight. The plasticizer is di(2-ethylhexyl) or dioctyl sebacate (5.3%), and the binder 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 at about 26,400 ft/s (8,040 meters per second or 18,000 mph or 28,900 km/h).
C-4 is made by combining RDX slurry with binder dissolved in a solvent. The solvent is then evaporated away and the mixture is dried and filtered. The final material is an off-white solid with a feel similar to modelling clay.
A major advantage of C-4 is that it can easily be moulded into any desired shape. C-4 can be pressed into gaps/voids in buildings, bridges, equipment or machinery. Similarly, it can easily be inserted into empty shaped-charge cases of the type used by special forces. C-4 is also well known for its durability, reliability, and safety. It will not explode even if hit by a bullet, punched, cut, or thrown into a fire. The only reliable method for detonation is via both heat and pressure, e.g. a detonator or blasting cap.
The remote C4 is effective against vehicles and buildings and has a tendency to stick to targets. The C4 explosives and it's derivatives were commonly used by all factions since it's development. Tanya Adams and other Allied commandos preferred it's small size yet high yield, as did special service engineers, commandos, the Ghostalker and similar. The C4 was phased out in favour of a more compact, yet even more high yield detonation packs after the First Tiberium War.