Plastic explosive

Plastic explosives contain one or more of the explosives listed above, moulded in an inert, flexible binder. Because powders do not readily hold a shape and TNT is the only common melt-castable explosive, most of the explosive powders (RDX, HMX, PETN, 1,3,5-triamino-2,4,6-trinitrobenzene (TATB)) are plasticized to make a mouldable material, for example, C-4, Semtex H, PE4, sheet explosive. A variety of plasticizers are added, but the maximum level is usually 10-15% because most plasticizers are inert and would degrade explosive output. Plastic explosives were originally developed for convenient use in military demolitions but have since been widely used in terrorist bombs. For detection techniques that rely on vapour signatures, such as canine olfaction, it is worth considering that the plasticizer is much more volatile than the explosive component. 

Plastic explosives, such as dynamites, are explosives rich in a liquid constituent, e.g. nitroglycerine, usually with dissolved high viscosity polymers. Guhr dynamite (no more in use) composed of 75% nitroglycerine and 25% kieselguhr, the first explosive to have a plastic consistency, owed this property to the high proportion of liquid it contained. 

Blasting gelatine and dynamites are now used only for civil purposes. Originally, they were suggested as military explosives, particularly for filling shells with a low muzzle velocity, until it was shown that fillings made with nitroglycerine explosives may cause premature explosions inside the barrel. 

The Russian air force used bombs filled with a material resembling blasting gelatine during World War I. 

Dynamites were retained for military purposes for some time for use in demolition charges. The disadvantage of these explosives lies in their limited chemical stability. Ultimately, therefore they were replaced by explosives that remain unchanged during storage (aromatic nitro compounds such as TNT, picric acid, and more recently TNT with cyclonite or PETN). 

The plasticity in an explosive can be put to practical use, e.g. for demolition purposes. Thus, to sever an iron bar or to blow up a wall or a rock the easiest way is to use a plastic explosive, moulded to fit the shape of the object to be destroyed. Since blasting gelatine is not entirely safe to handle, being elastic, i.e. difficult to shape as required, attention was directed to the development of plastic materials based on other constituents. Thus, mixtures comprising a solution of collodion cotton in liquid aromatic compounds as plasticizers were suggested. Such were Plastrotyl, recommended by Bichel [88] with a composition  

Individual chemicals may be so prepared or mixed to be suitable for use as either deflagrating or detonating explosives. Explosives find wide use as mining and constmction to blast ore, coal, and rock in petroleum prospecting and oil well production in manufacturing to bond metals and manufacture diamonds as pyrotechnics and in the aerospace Industry. Military explosives are used in demolition, ammunition, pyrotechnics, signals, and the like. 

In transportation terms, explosives are divided into six divisions (1.1 to 1.6) based on the (1) speed with which they react (2) sensitivity and modes of initiation (3) explosive power and (4) effects of the packaging or article to contain the explosive. 

Explosives are further assigned to one of thirteen compatibility groups (A through H, J, K, L, N, S) which identify the explosive article or substance and allow identification of other compatible explosives. 

A large number of chemicals, usually organic compounds of carbon, hydrogen, nitrogen, and oxygen, exhibit explosive properties  

Smokeless powders, solid low explosives, are virtually smokeless in comparison to black powder. They are also less susceptible to damp, store better, are more powerful, and bum at a more easily controlled rate. These benefits come with the disadvantage that they bum hotter and cause greater damage to the barrels of weapons in which they are used extensively as ammunition propellants. The length of a weapon s barrel and other ballistic requirements result in smokeless powder for pistol ammunition being in flakes, which bums quickly, while slower burning balls, cylinders, or tubes are used for rifle ammunition riflepowder). There are three types of smokeless powder  

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Voigt et al, Development of Plastic Explosives For HEP - Shell Filler , PATR 2176 (1955)... 

Examination of British Plastic Explosive, PE-3 A , PATR 2095 (1955) (Conf) 3) J. Cogan, Comparative Testing of United Kingdom Explosive PE4 and Composition C-4 , TechRept 1850-TR, Engineer Res Dev Labs, Ft Belvoir, Va (1960) (For Official Use Only)... 

Alicyclic amines are used as pesticides, plasticizers, explosives, inhibitors of metal corrosion and sweetening agents as well as having uses in the pharmaceuticals industry. Aniline hydrogenation has been studied in the literature with the main reaction products cyclohexylamine, dicyclohexylamine, A-phenylcyclohexylamine, diphenylamine, ammonia, benzene, cyclohexane, cyclohexanol and cyclohexanone [1-9], The products formed depend on the catalyst used, reaction temperature, solvent and whether the reaction is performed in gas or liquid phase. For example high temperature, gas-phase aniline hydrogenation over Rh/Al203 produced cyclohexylamine and dicyclohexylamine as the main products [1],... 

RDX may be used alone in pressed charges, although for this purpose tetryl is a more general choice. For shell and bomb fillings it is too sensitive alone to initiation by impact and friction and is either desensitised with wax, or else used like PETN in admixture with TNT. RDX may also be compounded with mineral jelly and similar materials to give a useful plastic explosive. 

A recent alternative to shaped charges is known as the squashhead projectile. As the name implies, this contains a plastic explosive which spreads on impact so as to make contact with the largest possible area of the tank before detonating. When the explosive detonates, reflection of the shock wave causes a scab of metal to be displaced from the inside surface of the armour plate (see p. 135). The effect inside the tank can therefore be greater than is the case with a shaped charge which may do little more than penetrate the armour. The amount of scabbing is approximately proportional to the area of contact of the explosive at the moment of detonation. 

Commercial and military explosives of one sort or another are in use around the globe. By far the most desirable ones for sabotage purposes are the military plastic explosives and TNT. 

Plastic explosives vary in composition and go by different names. The U.S. military has two versions C-3 and C-4. The British call theirs PE-2 and the Italians T-4. Other names used are RDX and, especially in Europe, Hexagen and Cyclonite. 

Both plastic explosives and TNT have the advantage of being very powerful while at the same time insensitive and quite safe to handle. Both also will retain their explosive properties after prolonged submersion and thus are excellent for underwater use. 

Since the shock of a single strand of primacord is not powerful enough to detonate most explosives, a knot must be tied at the end to concentrate explosive force within the charge to be detonated. A properly tied knot, securely buried, is sufficient to detonate plastic explosives. 

In priming plastic explosives with primacord, the triple roll knot (see Figure 5) is a good one to use. Three turns of the cord are concentrated in one tight knot, insuring detonation of the charge. 

Many of the more critical target structures in sabotage operations are made of steel. Plastic explosives are the best for steel cutting. They are easier to place and permit the use of a simple rule of thumb for determining the amount of explosive needed rather than working out a complicated mathematical formula. Also, if the proper techniques are used much less explosive is required to do the job than demolitions formulas call for. 

A strip of plastic explosive as thick as the steel to be cut, and as wide as it is thick, will cut through mild steel. This ribbon charge should be prepared in such a manner that it can be quickly placed and held in good contact against the steel where the cut is desired. See Figure 23. 

MATERIALS Wood scraps or tin strips, rags, string, blasting cap, plastic explosive. 

Slice layers of plastic explosive Vz to % inch thick with a sharp knife. Make the slices as even in thickness as possible, being careful not to destroy the density of the explosive. 

Split a half block of plastic explosive lengthwise and lay it open. Place the primacord lines and the two sliding knots between the two halves and adjust the knots so that one is just inside each end of the explosive. See Figure 27. 

MATERIALS Cord, string or rags, tape, prima-cord, plastic explosive, blasting caps, firing device. 

MATERIALS Martini or wine glass, beer can or other tubular container or cardboard from which to fashion one, sticks, tape or string, plastic explosive. 

PLASTIC EXPLOSIVE PACKED INTO CONTAINER FIRMLY, AROUND AND BEHIND MARTINI GLASS... 

MATERIALS Wine bottle with a cavity base, tubular container, sticks, tape or string, mop string, fiber cord or shoelace, gasoline, bucket of cold water, plastic explosive. 

Pack plastic explosive densely against one side of the plate, completely covering it. Use about the same amount of explosive as the weight of the plate. 

The main value of the counterforce technique is that it requires only half the explosive needed to accomplish the same result using standard formulas and placement. For example, a 14 inch diameter timber which requires 3% pounds of plastic explosive to cut conventionally can be sheared in two with counterforce charges of % pound each. Reinforced concrete piers 2 feet by 2 feet which can be broken conventionally by 17 pounds of explosive can be broken by counterforce charges of 4 pounds each. 

MATERIALS Tape, cord, containers for explosive, primacord, blasting caps, plastic explosive. 

Pack plastic explosive densely into two identical containers—such as jar lids with an adequate lip or the bottom portions of tin cans. The size of the containers and the amount of explosive will depend upon the type and size of the target. Po-... 

MATERIALS Paper or cloth, tape, blasting caps, primacord, plastic explosive. 

SLICE PLASTIC EXPLOSIVE INTO THIN STRIPS AND LAY ON DIAMOND. TRIM TO SHAPE... 

MATERIALS Tin can or bottle, sand, stones, strong cord, TNT or plastic explosive, nonelectric blasting cap, delay firing device (time pencil or time fuse). 

Prepare a charge of TNT or plastic explosive % to 1 pound in weight. 

MATERIALS Metal fragments (nails, washers, bolts, nuts, etc.), rags, wire, tape, or string, container, primacord and/or blasting caps, plastic explosive or dynamite. 

Many types of mortar shells are packed unassembled in separate containers. In such cases one need only fill the fuse well with plastic explosive and prime it with a primacord triple roll knot. Others, including U.S. shells, are packed fully assembled. Following are the steps to be taken to prepare a fully assembled shell for use as an ambush charge ... 

Tie a triple roll knot in the end of primacord of whatever length is needed for- a branch line. Insert the knot into the open fuse well of the mortar shell, and pack plastic explosive around it. Fasten the explosive and knot in place with tape, wire, or string. See Figure 49. 

Another way of priming the charge is to use the booster which is present in the fuse assembly instead of plastic explosive. To do this, leave the wrench on the fuse after it is removed from the shell, grip the booster cup with pliers and unscrew the booster from the fuse. 

Any number of mortar shells may be prepared either with the plastic explosive technique or by using the booster and attached by their primacord branch lines to a main primacord line for simultaneous firing. Or they may be interspersed along a road or trail with frag grenades or other improvised charges. 

If the booster is not used, the warhead may be primed by filling the cavity in the top with plastic explosive, into which is embedded and fastened a blasting cap or a primacord knot. 

Mix equal parts of explosive and thermate incendiary. A powdered explosive is easiest to use, and TNT may be safely crushed with a wooden implement in a wooden container. Plastic explosive or dynamite also may be used, although in this case the explosive should be placed under the thermate so that the thermate will be directed upward. The thermate can be obtained from the AN M-14 incendiary grenade or homemade as described in the section on improvised incendiaries. ... 

MATERIALS Fuel-tight container (approximately 2 gallon volume), plastic explosive, ther-mate, primacord, nonelectric blasting cap, delay device. 

Pack about 2 pounds of plastic explosive tightly into the bottom of the container and imbed the triple roll knot in it. 

Add another layer of plastic explosive equal to the bottom layer and be sure the girth hitch knot is imbedded in this layer. The sandwiched layers of explosive and thermate should occupy no more than the bottom two-thirds of the container, the rest being open air space to provide buoyancy when the container is sealed. It is advisable to test the buoyancy of the charge (in fuel oil or gasoline, not water) prior to placement in the target. If additional buoyancy is needed, a block of wood can be added in the top of the container. 

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