C4 is composed of explosives, plastic binder, plasticizer and usually a marker or odorizing taggant chemical such as 2,3-dimethyl-2,3-dinitrobutane (DMDNB) to help detect the explosive and identify its source.
The explosive in C4 is RDX (cyclonite or cyclotrimethylene trinitramine), which makes up around 91% of C4 by mass. The plasticizer is diethylhexyl (5.3%) or dioctyl sebacate and the binder is usually 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. C4 is manufactured by combining the noted ingredients 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 texture similar to modelling clay.
Characteristics and uses
A major advantage of C4 is that it can easily be molded into any desired shape. C4 can be pressed into gaps, cracks, holes and voids in buildings, bridges, equipment or machinery. Similarly, it can easily be inserted into empty shaped charge cases of the type used by military engineers.
C4 is very stable and insensitive to most physical shocks. C4 cannot be detonated by a gunshot or by dropping it onto a hard surface. It does not explode when set on fire or exposed to microwave radiation. Detonation can only be initiated by a combination of extreme heat and a shockwave, such as when a detonator inserted into it is fired.
Use in the Vietnam War
When ignited with a flame rather, C4 simply burns, and sometimes American soldiers allegedly would use small amounts to heat C-rations. However, this seems unlikely, since C-rations were already warmed by the semi-tropical climate, and soldiers were warned against burning C4, as it gives off poisonous fumes.
Michael Herr in Vietnam War book Dispatches, claims that a soldier might occasionally ingest C4 to cause temporary illness and be sent on sick leave. However, experienced officers were usually aware of the ruse.
The British military uses a very similar plastic explosive known as PE4. Like C4, it is an off-white colored solid and its explosive characteristics are nearly identical to C4. The type and proportion of plasticizer used differs, and PE4 has a slightly greater velocity of detonation, 8,210 m/s (26,900 ft/s). Semtex is a somewhat similar plastic explosive.
- "Explosives – Compounds". Global Security.
- "C4 product page". Ribbands Explosives.
- MythBusters, Season 9, Episode 17: "C4 Cook-Off"
- MythBusters, Season 7, Episode 15: "Microwave Mayhem"
- US Army Field Manual 5–250, Explosives and Demolitions includes this bold print, block warning: "WARNING Composition C4 explosive is poisonous and dangerous if chewed or ingested; its detonation or burning produces poisonous fumes."
- Michael Herr, (1977). Dispatches. Knopf. ISBN 0679735259.
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