Explosives And Demolitions

■ 45. The Job of Destruction.—a. As an engineer soldier, one of your most important jobs is the handling of explosives and demolition tools. It takes training to become an expert demolition man. There is a great deal to learn. In this chapter you will flnd enough fundamentals to give you a good start. With these essentials and with experience you can gradually become an expert.

b. You must learn this job thoroughly. It is a great responsibility. When you are given the Job of blowing up a bridge, a road, or a building, that bridge, or road, or building must be destroyed at the specified time. There can be no mistakes. Demolitions are usually ordered at critical times; and the failure of a single demolition may cost the lives of hundreds of men. You must not fail.

■ 45. Equipment.—Demolition sets are issued to all general engineer units and many special engineer units. Each set includes a supply of explosives and the necessary tools and equipment for preparing, priming, and firing demolition charges. Earth-drilling tools, wood augers, and rock drills required for placing chargcs arc available in pioneer and carpenter sets.

oft. In small quantities it can be burned without danger of detonation, but in large quantities the heat generated will raise the temperature to the detonating point. TNT will nol dissolve in water and hence is suitable for underwater demolition work.

b. Nitrostarc)i.—Nitrostarch is issued in \'2 -pound, cardboard-covered blocks of the same size and shape as TNT. and In l-pouhd paper-wrapped packages. Each of the 1-pound packages is made up of four VV-pound packages, which, in turn, are made up of three 1 u-pound blocks. Each of these blocks has a cap hole extending all the way through it. Nitrostarch is similar in many respects to TNT.

c. Dynamite.—Dynamite is issued in approximately impound sticks, approximately lft inches in diameter and 8 Inches in length. Fifty pprrent straight dynamite Sa equal in strength (pound for pound) to TNT. It is much mor* sensitive than TNT and may bo detonated by a blow with a metal instrument, or by flying sparks struck from metiw striking metal. When frozen it is especially dangerous an' must be handled with extreme care.

d. Ammonium nitrate crateiiuy explosive (Jiff. U4).—Am monium nitrate cratering explosive is issued in 40-pouncf

■ 47. Explosives.—a. TNT.—(1) TNT (trinitrotoluene) is the standard explosive for Army use. It 1s issued In Vz•» pound blocks encased in a cardboard container closed at both ends with lacquered tin (flg. 81). One end of each block has a cylindrical hole, approximately inch in diameter and 2*4 Inches long, for receiving the cap.

(2) TNT is one of the safest explosives to handle, if you know how to use it. It is insensitive to shock and will not detonate even under strong pressure or severe blows. It requires the special issue cap or detonating cord to set it

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charges, each packed in a cylindrical container of tin or other moistureproof material of equal strength. The metal container is about 8V4 Inches in diameter and 17 inches in height; another type of container, made of waterproofed cardboard, is 7 inches in diameter and about 21 inches high Two tubes arc secured to the outside wall of each container,

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one for receiving the detonating cord, and the other the special cap. If exposed to air, ammonium nitrate explasiVe absorbs moisture rapidly; consequently, it must never be removed f rom the container. It is used principally in making crater obstacles for tanks and other motorized vehicles.

■ 40. Bangalore Torpedo.—a. The bangalore torpedo is a metal tube or pipe filled with explosives. Its primary uses are to cut gaps in barbed wire obstacles and to cause detonation of mines. The standard bangalore torpedo, about 2 inches in diameter, is issued in 5-foot watertight sections already filled with explosives. Sleeves are provided for connecting sections to extend torpedoes to any desired length. By fastening the rounded nose on the forward end, you can push the torpedo through a band oi barbed wire without getting it caught on the wires.

b. To explode the torpedo, an electric or nonelectric cap, or primacord. is inserted in the cap well in the trailing end of the torpedo. When several sections are joined to form a long torpedo, it is neccssary to place a cap only in the last section, since detonation of one section will cause the whole torpedo to explode. If standard-type torpedoes are not available, you can make bangalore torpedoes by filling a pipe (for example, a 2-inch water pipe or an old drain pipe) with explosives; the ends are closed with wooden plugs, and one end is primed by making a hole through one of the plugs; a primer made with TNT block and primacord is placed inside the torpedo and the primacord end is drawn through the hole in the wooden block.

c. Remember that each 5-foot section of the bangalore torpedo is loaded with about ID pounds of high explosive, and the same precautions in handling and firing must be taken as when other military high explosives are used.

■ 49. Firing Materials.—a. Caps (figs. 82 and 83).—Caps are placed in charges to set them off. Standard commercial caps will not detonate TNT or ammonium nitrate craterlng charge: therefore the army has adopted a special cap. Caps are classified as electric or nonelectric, depending on whether they are set off by electricity or fuze. Both types must be

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handled with great care, because they may be set off by dropping or hitting them, or exposing them to excessive heat.

b. Exploders.—Exploders are used to supply electric current to set off elcctric caps. The 10-cap exploder is operated by a quick twist of the handle. The 30-cap exploder is operated by slowly pulling the handle all the way up and then pushing it all the way down as fast and as hard as possible.

c. Firing wire.—Firing wire, carried on ft metal reel, is used to connect the exploder to wires of electric caps placed in chargcs. It is issued in 500-foot lengths so that a man may fire the charge from a safe distance. Cap wires are connected to the free end of the firing wire, and the exploder is connected to the end which is fixed to the metal reel. When extremely large charges or steel-cutting charges are being fired, two or more reels of wire may be connccted so as to enable the flrer to fire the charge from a distance of 1,000 feet or more.

d. Time fuze.—A time fuze Is used to set off nonelectric cups. It consists of a train of black powder contained in a waterproofed textile covering which may be either white or orange. When using a time fuze, cut it to the desired length and crimp one end In the nonclcctric cap. Light the other end with a match or fuze lighter after the explosive charge has been prepared. Always be sure to use a fuze long enough to enable you to reach a place of safety before the charge explodes. A time fuze burn3 at the rate of about 2 feet per minute.

t. Fuze lighter.—The fuze lighter (fig. 84) is used to light a time fuze. The open end is placed over the end of the time fuze where it i3 held In place by means of teeth Inside the fuze lighter. These teeth permit the fuze to enter, but are inclined so as to bind the fuze and prevent its removal. It is unnecessary to crimp the lighter. Pulling the handle causes a flame inside the lighter which lights the fuze even in wet or windy weather, if the lighter and the powder train in the fuze have been kept dry. The fuze lighter should be set. off by means of a steady pull (.not a jerk). (Fig. 100 shows how to Improvise a fuze lighter.)

/. Detonating cord.—A detonating cord consists of a train

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