C4 or
Composition C4 is a common variety of the
plastic explosivePlastic explosive is a specialised form of explosive material. It is a soft and hand moldable solid material. Plastic explosives are properly known as putty explosives within the field of explosives engineering....
known as
Composition CThe Composition C family is a family of related US-specified plastic explosives consisting primarily of RDX. All can be moulded by hand for use in demolition work and packed by hand into shaped charge devices. Variants have different proportions and plasticisers and include C-2, C-3, and C-4.The...
.
Composition and manufacture
C4 is made up of explosives, plastic binder,
plasticizerPlasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...
and usually marker or odorizing
taggantA taggant can mean a radio frequency microchip used in automated identification and data capture . In such cases, electronic devices use radio waves to track and identify items, such as pharmaceutical products, by assigning individual serial numbers to the containers holding each product...
chemicals such as 2,3-dimethyl-2,3-dinitrobutane (
DMDNBDMDNB, or also DMNB, chemically 2,3-dimethyl-2,3-dinitrobutane, is a volatile organic compound used as a detection taggant for explosives, mostly in the United States where it is virtually the only such taggant in use. Dogs are very sensitive to it and can detect as little as 0.5 parts per billion...
) to help detect the explosive and identify its source.
The explosive in C4 is
RDXRDX, an initialism for Research Department Explosive, is an explosive nitroamine widely used in military and industrial applications. It was developed as an explosive which was more powerful than TNT, and it saw wide use in WWII. RDX is also known as cyclonite, hexogen , and T4...
(cyclonite or cyclotrimethylene trinitramine), which makes up around 91% of C4 by mass. The plasticizer is diethylhexyl (5.3%) or
dioctyl sebacateDioctyl sebacate 82, or di sebacate, is an organic compound which is the diester of sebacic acid and 2-ethylhexanol. It is an oily colorless liquid and is used as a plasticizer. Most commonly in C4. It has also found use in Dot 5 brake fluid.-Physical properties:Relative vapour density :...
and the binder is usually polyisobutylene (2.1%).
Another plasticizer used is
dioctyl adipateDioctyl adipate or DOA is a plasticizer. DOA is a diester of adipic acid and two equivalents of n-octanol. Its chemical formula is 22424.DEHA is sometimes incorrectly called 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 clayYou can use modelling clay to create items with it. The material compositions and production processes vary considerably. -Ceramic clay:...
.
Advantages
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 chargeA shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
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 than detonated with a primary explosive, C4 burns slowly, so soldiers during the
Vietnam WarThe Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
era would sometimes use small amounts of it as a
fuelFuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
for heating rations. Burning C4 produces poisonous fumes and should be avoided.
Michael HerrMichael Herr is a writer and former war correspondent, best known as the author of Dispatches , a memoir of his time as a correspondent for Esquire magazine during the Vietnam War...
in
DispatchesDispatches is a New Journalism book by Michael Herr that describes the author's experiences in Vietnam as a war correspondent for Esquire magazine. First published in 1977, Dispatches was one of the first pieces of American literature that allowed Americans to understand the experiences of soldiers...
, his book about the Vietnam War, relates that a soldier would occasionally ingest C4 from a Claymore mine in order to cause temporary illness so that he would be sent on sick leave. Although the ruse might work with an inexperienced commander, experienced officers were usually aware of the trick and would keep the man on board.
Similar compounds
The British military uses a plastic explosive referred to as PE4. Like C4, it is an off-white colored solid and its explosive characteristics are nearly identical to C-4. The type and proportion of plasticizer used differs, and PE4 has a slightly greater velocity of detonation, 8210 m/s (26,935.7 ft/s).
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