8/14/2019 Chapter 1 Military Explosives http://slidepdf.com/reader/full/chapter-1-military-explosives 1/22 FM 5-250 Chapter 1 Military Explosives Section I. Demolition Materials 1-1. Characteristics. To be suitable for use in military operations, explosives must have certain properties. Military explosives— Should be inexpensive to manufacture and capable of being produced from readily available raw materials. Must be relatively insensitive to shock or friction, yet be able to positively detonate by easily prepared initiators. Must be capable of shattering and must have the potential energy (high energy output per unit volume) adequate for the purpose of demolitions. Must be stable enough to retain usefulness for a reasonable time when stored in temperatures between -80 and +165 degrees Fahrenheit. Should be composed of high-density materials (weight per unit volume). Should be suitable for use underwater or in damp climates. Should be minimally toxic when stored, handled, and detonated. 1-2. Selection of Explosives. Select explosives that fit the particular purpose, based on their relative power. Consider all characteristics when selecting an explosive for a particular demolition project. See Technical Manual (TM) 9-1300-214 for detailed information on military explosives. Table 1-1 (page 1-2) contains significant information regarding many of the explosives described below. 1-3. Domestic Explosives. a. Ammonium Nitrate. Ammonium nitrate is the least sensitive of the military explosives. It requires a booster charge to successfully initiate detonation. Because of its low sensitivity, ammonium nitrate is a component of many composite explosives (combined with a more sensitive explosive). Ammonium nitrate is not suitable for cutting or breaching charges because it has a low detonating velocity. However, because of its excellent cratering affects and low cost, ammonium nitrate is a component of most cratering and ditching charges. Commercial quarrying operations use ammonium nitrate demolitions extensively. Pack ammonium nitrate in an airtight container because it is extremely hydroscopic (absorbs humidity). Ammonium nitrate or composite explosives containing ammonium nitrate are not suitable for underwater use unless packed in waterproof containers or detonated immediately after placement. b. Pentaerythrite Tetranitrate (PETN). PETN is a highly sensitive and very powerful military explosive. Its explosive potential is comparable to cyclonite (RDX) and nitroglycerin. Boosters, detonating cord, and some blasting caps contain PETN. It is also used in composite explosives with trinitrotoluene (TNT) or with nitrocellulose. A PETN-nitrocellulose composite (Ml 18 sheet explosive) is a demolition charge. it is almost insoluble in water. The PETN explosive is a good underwater-demolition because 1-1
1-1. Characteristics. To be suitable for use in military operations, explosives must have certainproperties. Military explosives—
Shou ld be inexpensive to man ufacture and capable of being p rod uced from read ilyavailable raw materials.
Must be relatively insensitive to shock or friction, yet be able to positively detonate byeasily prepared initiators.
Must be capable of shattering and mu st have the potential energy (high energy outpu tper u nit volume) adequate for the purp ose of demolitions.
Must be stable enough to retain usefulness for a reasonable time when stored intemperatures between -80 and +165 degrees Fahrenheit.
Should be composed of high-density materials (weight per unit volume).
Should be suitable for use un derwater or in dam p climates.
Should be minimally toxic when stored, handled, and detonated.
1-2. Selection of Explosives. Select explosives that fit the particular p ur pose, based on theirrelative power. Consider all characteristics when selecting an explosive for a particular demolitionproject. See Technical Manual (TM) 9-1300-214 for detailed information on military explosives.Table 1-1 (page 1-2) contains significant information regard ing m any of the explosives describedbelow.
1-3. Domestic Explosives.
a. Ammonium Nitrate. Ammonium nitrate is the least sensitive of the military explosives. Itrequ ires a booster charge to successfully initiate detonation. Because of its low sensitivity,ammonium nitrate is a component of many composite explosives (combined with a more sensitiveexplosive). Ammonium nitrate is not suitable for cutting or breaching charges because it has a lowdetonating velocity. How ever, because of its excellent cratering affects and low cost, amm oniumnitrate is a comp onent of most cratering and d itching charges. Commercial quarrying op erationsuse ammonium nitrate demolitions extensively. Pack ammonium nitrate in an airtight containerbecause it is extremely hydroscopic (absorbs hu midity). Ammonium nitrate or compositeexplosives containing ammonium nitrate are not suitable for underwater use unless packed in
waterproof containers or detonated immediately after placement.
b. Pentaerythrite Tetranitrate (PETN). PETN is a highly sensitive and very powerful militaryexplosive. Its explosive potential is comparable to cyclonite (RDX) and nitroglycerin. Boosters,detonating cord, and some blasting caps contain PETN. It is also used in composite explosives withtrinitrotolu ene (TN T) or w ith nitrocellulose. A PETN-nitrocellulose comp osite (Ml 18 sheetexplosive) is a demolition charge.it is almost insoluble in water.
The PETN explosive is a good un derw ater-demolition because
c. Cyclotrimethlenetrinitramine (RDX). RDX is also a highly sensitive and very powerfulmilitary explosive. It forms the base charge in the M6 electric and M7 nonelectric blasting caps.When RDX is desensitized, it serves as a subbooster, booster, bursting charge, or demolition charge.The principal use for RDX is in composite explosives, such as Composition A, B, and C explosives.RDX is available commercially under the name cyclonite.
d. Trinitrotoluene. TNT is the most common military explosive. It m aybe in comp osite form,such as a booster, a bursting, or a dem olition charge, or in a noncomp osite form. Since TNT is astandard explosive, it is used to rate other military explosives.
e. Tetryl. Tetryl is an effective booster charge in its noncomp osite form and a bu rsting or ademolition charge in composite forms. Tetryl is more sensitive and powerful than TNT. However,
RDX- and PETN-based explosives, which have increased power an d shattering effects, are replacingtetryl and composite explosives containing tetryl.
f. Nitroglycerin. N itroglycerin is one of the most powerful high exp losives. Its explosivepotential is comp arable to RDX and PETN. Nitroglycerin is the explosive base for commercialdynamites. Nitroglycerine is highly sensitive and extremely temperature-sensitive. Militaryexplosives do not use nitroglycerin because of its sensitivity. Do not use commercial dynamites incombat areas.
g. Black Powder. Black powd er is the oldest-known explosive and prop ellant. It is a comp ositeof potassium or sod ium n itrate, charcoal, and su lfur . Time fuses, some igniters, and some detonatorscontain black p owder.
h. Amatol. Amatol is a mixture of ammonium nitrate and TNT. It is a substitute for TNT inbursting charges. Some older bangalore torpedoes use 80-20 amatol (80 percent ammonium nitrateand 20 percent TNT). Because am atol contains am monium nitrate, it is a hyd roscopic comp oun d.Keep any explosives containing amatol in airtight containers. If properly packaged, amatol remainsviable for long periods of time, with no change in sensitivity, power, or stability.
i. Composition A 3. Composition A3 is a composite explosive containing 91 percent RDX and9 percent wax. The purp ose of the wax is to coat, desensitize, and bind the RDX particles.Composition A3 is the booster charge in some newer shaped charges and bangalore torpedoes.High-explosive plastic (HEP) projectiles may also contain Composition A3 as a main charge.
j. Composition B. Com position B is a comp osite explosive contain ing ap pr oximately 60
per cent RDX, 39 percent TNT, and 1 percent wax. It is more sensitive th an TNT. Because of itsshattering power and high rate of detonation, Composition B is the main charge in shaped charges.
k. Composition B4. Composition B4 contains 60 percent RDX, 39.5 percent TNT, and 0.5percent calcium silicate. Comp osition B4 is the main charge in newer mod els of bangaloretorpedoes and shap ed charges.
l. Composition C4 (C4). C4 is a composite explosive containing 91 percent RDX and 9 percentnonexplosive plasticizers. Bur ster charges are comp osed of C4. C4 is effective in tem peratu resbetween -70 to+ 170 degrees Fahrenheit; however, C4 loses its p lasticity in the colder tem peratu res.
m. Tetrytol. Tetrytol is a composite explosive containing 75 percent tetryl and 25 percent TNT.
It is the explosive comp onent in d emolition charges. Booster charges require d ifferent m ixtures of tetryl and TNT. Tetrytol is more powerful than its ind ividual components, is better at shatteringthan TNT, and is less sensitive than tetryl.
n. Pentolite. Pentolite is a m ixture of PETN an d TNT. Because of its high p ower anddetonating rate, a mixtur e of 50-50 pen tolite (50 percent PETN and 50 percent TNT) ma kes aneffective booster charge in certain m odels of shap ed charges.
(1) Standard Dynamite. Most dynamites, with the notable exception of military dynamite,contain nitroglycerin p lus var ying combinations of absorbents, oxidizers, antacid s, andfreezing-point depressants. Dynamites vary greatly in strength and sensitivity depending on, amongother factors, the p ercentage of nitroglycerin th ey contain. Dynamites are for general blasting anddemolitions, including land clearing, cratering and ditching, and quarrying.
(2) Military Dynamite. Military dynamite is a composite explosive that contains 75 percentRDX, 15 percent TNT, and 10 percent desensitizers and plasticizers. Military dynamite is not aspowerful as commercial dynamite. Military d ynam ite’s equ ivalent strength is 60 percent of commercial dynamiters. Because military dynamite contains no nitroglycerin, it is more stable andsafer to store and handle than commercial dynamite.
1-4. Foreign Explosives.
a. Composition. Foreign countries use a variety of explosives, including TNT, picric acid,amatol, and gun cotton. Picric acid is similar to TNT, but it also corrodes metals and thu s formsextremely sensitive compounds.
WARNINGDo n ot use picric acid in rusted or corroded m etal containers.
Do n ot han dle p icric acid. Notify explosive ordnan ce disposal (EOD ) personnelfor disposition.
b. Use. You may use the explosives of allied nations and those captured from the enemy tosupplement standard supplies. Only expert demolitionists should use such explosives and then onlyaccording to instructions and directives of theater commanders. Captured bombs, propellants, andother devices may be used with US military explosives for larger demolition projects, such as pier,bridge, tunnel, and airfield destruction. Most foreign explosive blocks have cap wells large enoughto receive US military blasting caps. Since foreign explosives may differ from US explosives in
sensitivity and force, test shots should be made to determine their adequacy before extensive use ormixing with US-type explosives.
Section II. Service Demolition Charges
1-5. Block Dem olition Charges. Block demolition charges are prepackaged, high-explosivecharges for general dem olition operations, such as cutting, breaching, and cratering. They arecomposed of the high-explosive TNT, tetrytol, Comp osition-C series, and am m onium nitrate.Block charges are rectangular inform except for the 40-pound, ammonium-nitrate block demolitioncharge, military dynamite, and the ¼-pound-TNT block demolition charge, which are all cylindricalin form. The various block charges available are described in the text that follows, as well as Table1-2. See TM 43-0001-38 for detailed information about demolition charges and accessories.
a. Characteristics. The M112 block dem olition char ge consists of 1.25 pou nd s of C4 pa ckedin an olive-drab, Mylar-film container with a pressure-sensitive adhesive tape on one surface (Figure1-2). The tape is protected by a peelable paper cover. Table 1-2 (page 1-5) lists additionalcharacteristics of the Ml12 block.
b. Use. The M112 block demolitioncharge is used p rimarily for cutting an d
breaching. Because of its high cutting effectand its ability to be cut and shaped, the M1l2charge is ideally suited for cutting irregularlyshaped targets such as steel. The adhesivebacking allows you to place the charge on anyrelatively flat, clean, dry surface with a
temperature that is above the freezing point. The Ml12 charge is the primary block demolitioncharge presently in use.
WARNING
Composition C4 explosive is poisonous and dangerous if chewed oringested; its detonation or burn ing prod uces poisonous fumes. Cut allplastic explosives with a sharp steel kn ife on a non sparkin g surface.
Do not use shears.
c. Advantages. You can cut to shape the M112 block demolition charge to fit irregularly shapedtargets. The color of the wrap per h elps camouflage the charge. Molding the charge w ill decreaseits cutting effect.
d. Limitations. The adhesive tape w ill not ad here to w et, dirty, rusty, or frozen su rfaces.
1-8. M118 Block D emolition Charge.
a. Characteristics. The M118 block dem olition ch arge, or sh eet explosive, is a block of four½-pound sheets of flexible explosive packed in a plastic envelope (Figure 1-3). Twenty Ml18charges and a package of 80 M8 blasting-cap holders ar e packed in a w ooden box. Each sheet of the explosive has a p ressure-sensitive adhesive tape attached to one surface. Table 1-2 (page 1 -5)lists add itional characteristics for the M118 charge.
1-6
b. Use. The Ml18 charges are d esigned forcutting, especially against steel targets. Thesheets of explosive are easily and quicklyapplied to irregular and curved surfaces and are
easily cut to any desired d imension. The Ml18charge is effective as a small breaching chargebut, because of its high cost, it is not suitable asa bulk explosive charge.
c. Advantages. The flexibility and adh esive backing of the sheets allow ap plication to a largevariety of targets. You can cut the ½-pound sheets to any desired dimension and apply them inlayers to achieve the desired thickness. The Ml18 charge is not affected by water, making itacceptable for underwater demolitions.
d. Limitations. The adhesive tape will not adhere to wet, dirty, rusty, or frozen surfaces.
1-9. M186 Roll Dem olition Charge.
a. Characteristics. The Ml86 roll dem olition char ge, show n in Figu re 1-4, is iden tical to theMl18 block demolition charge except that the sheet explosive is in roll form on a 50-foot, plasticspool. Each foot of the roll provid es app roximately a half poun d of explosive. Included with eachroll are 15 M8 blasting cap h olders and a canvas bag with carrying strap. Table 1-2 (page 1-5) listsadditional characteristics for the M186 charge.
b. Use. Use the M186 roll demolition charge in the same manner as the Ml18 block demolitioncharge. The Ml86 charge is adaptable for demolishing targets that require the use of flexibleexplosives in lengths longer than 12 inches.
c. Advantages. The Ml86 roll demolition charge has all the advantages of the Ml18 block
dem olition charge. You can cut the M186 charge to the exact lengths desired.d . Limitations. The adhesive backing w ill not ad here to w et, dirty, rusty, or frozen surfaces.
1-10. Forty-Pound , Ammon ium -Nitrate Block D emolition Charge
a. Characteristics. Figure 1-5 (page 1-8) shows the 40-pound, ammonium-nitrate block dem olition charge or cratering charge. It is a w atertight, cylindrical metal container w ithapp roximately 30 poun ds of an amm onium -nitrate-based explosive and 10 pou nd s of TNT-basedexplosive booster in the center, next to the p riming tu nnels. The tw o pr iming tu nnels are locatedto the outside of the container, midw ay between th e ends. One tun nel serves as a cap w ell forprim ing the charge w ith an M6 electric or M7 nonelectric military blasting cap. The other tun nelseries as a priming path, with the detonating cord passing through the tunn el and knotted at the end.
There is a cleat between the tunnels to secure the time blasting fuse, electrical firing wire, ordetonating cord. There is a metal ring on th e top of the container for lowering the charge into itshole. Table 1-2 (page 1-5) lists additional characteristics for the 40-pound, ammonium-nitrate blockdemolition charge.
b. Use. This charge is suitable for cratering and ditching operations. Its primary use is as acratering charge, but it also is effective for destroying bu ildings, fortifications, and bridge abutm ents.
c. Advantages. The size and sh ape of this charge m ake it ideal for cratering op erations. It isinexpensive to produce compared to other explosives.
d. Limitations. Ammonium nitrate is hydroscopic. When wet, it will not detonate. To ensuredetonation, use metal containers show ing no evidence of water damage. Detonate all charges placedin wet or damp boreholes as soon as possible.
1-11. Ml M ilitary Dyn amite.
a. Characteristics. M1 m ilitary d ynam ite is an RDX-based composite explosive containingno nitroglycerin (Figure 1-6). M 1 dynamite is packaged in ½-pound, paraffin-coated, cylindricalpap er cartridges, which have a n ominal d iameter of 1.25 inches and a nom inal length of 8 inches.Table 1-2 (page 1-5) lists additional characteristics for Ml military dynamite.
b. Use. Ml dyn amite’s primary uses aremilitary construction, quarr ying, ditching, an dservice dem olition work. It is suitable forund erwater demolitions.
c. Advantages. Ml dyn am ite will not freezeor perspire in storage. The Ml dy nam ite’scomposition is not hydroscopic. Shippingcontainers do not requ ire turning du ring storage.Ml d ynam ite is safer to store, hand le, andtransp ort than 60-percent comm ercial dynam ite.Unless essential, do not u se civilian d ynam ite in
combat areas.
d . Limitations. Ml d ynam ite is reliable u nd erw ater only for 24 hour s. Because of its lowsensitivity, pack sticks of military dynamite w ell to ensure complete detonation of the charge. Mldynamite is not efficient as a cutting or breaching charge.
b. Use. A shaped demolition charge’s primary use is for boring holes in earth, metal, masonry,concrete, and paved and unpaved roads. Its effectiveness depend s largely on its shape, composition,and placement. Table 1-3, lists the penetrating capabilities of various materials and the properstandoff distances for these charges.
c. Special Precautions. To achieve the ma ximu m effectiveness of shap ed charges—Center the charge over the target point.
Align the axis of the charge w ith the d irection of the desired h ole.
Use the pedestal to obtain the proper standoff distance.
Susp end th e charge at the p roper h eight on pickets or tripods, if the ped estal does notprovide the proper standoff distance.
Remove any obstruction in the cavity liner or between the charge and the target.
1-13. M183 Demolition Charge Assembly.
a. Characteristics. The Ml83 demolition charge assembly or satchel charge consists of 16M112 (C4) dem olition blocks and 4 priming assemblies. It has a total explosive w eight of 20pou nd s. The d emolition blocks come in tw o bags, eight blocks per bag. The tw o bags come in anM85 canvas carrying case. Tw o M85 cases come in a w ood en box 17 1/ 8 by 11½ by 12½ inches.Each priming assembly consists of a 5-foot length of detonating cord with an RDX booster crimpedto each end and a p air of Ml detonating-cord clips for attaching the pr iming assembly to a detonatingcord ring or line main.
b. Use. The M183 assembly is used primarily forereaching obstacles or demolishing structureswhen large demolition charges are required (Figure 1-8). The M183 charge also is effective againstsmaller obstacles, such as small dragon’s teeth.
c. Detonation. Detonate the Ml83 demolition charge assembly with a priming assembly andan electric or a nonelectric blasting cap or by using a detonating-cord ring main attached bydetonating cord clips.
1-14. M1A2 Bangtlore-Torpedo Demolition Kit.
a. Characteristics. Each k it consists of 10 loading assemb lies, 10 connecting sleeves, and 1nose sleeve. The loading assemblies, or torp edoes, are steel tubes 5 feet long an d 2 1/ 8 inches indiameter, grooved, and capped at each end (Figure 1-9, page 1-12). The torpedoes have a 4-inch,Composition A3 booster (½ pound each) at both ends of each 5-foot section. The main explosivecharge is 10½ pou nd s of Composition B4. The kit is packaged in a 60¾- by 13¾- by 4 9 / 16-inchwooden box and w eighs 198 pound s.
b. Use. The primary u se of the torped o is clearing p aths throu gh w ire obstacles and h eavyun dergrow th. It will clear a 3- to 4-meter-wide path throu gh w ire obstacles.
WARNINGThe Bangalore torpedo may d etonate a live mine w hen being placed.
To prevent detonation of the torpedo during placement, attach the nose sleeveto a fabricated dummy section (approximately the same dimensions
as a single Bangalore section) and p lace the d um my section onto the front endof the torpedo.
c. Assembly. All sections of the torpedo have th readed cap w ells at each end. To assembletwo or m ore sections, press a nose sleeve onto one end of one tube, and th en connect successivetubes, using the connecting sleeves provided until you have the desired length. The connectingsleeves make rigid joints. The nose sleeve allows the u ser to push the torpedo through en tanglementsand across the ground.
d . Detonation. The recommended method to detonate the torpedo is to prime the torpedo witheight wrap s of detonating cord and attach two initiation systems for detonation. Another methodfor prim ing the Bangalore torp edo is by inserting an electric or a nonelectric blasting cap d irectlyinto the cap well. Do not move the torpedo after it has been prepared for detonation. You maywrap the end w ith detonating cord p rior to placing it, but d o not attach the blasting caps un til thetorpedo is in place.
1-15. M180 Dem olition Kit (Craterin g).
a. Characteristics. This kit consists of an M2A4 shaped charge, a modified M57 electricalfiring device, a warh ead, a rocket motor, a tripod, and a d emolition circuit (Figure 1- 10). The shap edcharge, firing device, and war head are perm anently attached to the launch leg of the tripod . Therocket motor and the demolition circuit (packed in a wooden subpack) are shipped separately. The
kit weighs ap proximately 165 pound s (74.25 kilogram s). TM 9-1375-213-12-1 provides theassembly procedures, operational description, and maintenance instructions for the Ml80 kit.
b. Use. The M180 is designed to p rod uce a large crater in comp acted soil or road surfaces,but not in r einforced concrete, arctic tund ra, bedrock, or sand y soil. The charge p rodu ces a craterin tw o stages. The shap ed charge b lows a p ilot hole in th e surface. Then, the rocket-propelledwarhead enters the h ole and d etonates, enlarging the p ilot hole. Up to five kits can be set up closetogether and fired simultaneously to p rodu ce an exceptionally large crater. Up to 15 kits can be
widely spaced and freed simultaneously for airfield pocketing.
WARNINGRegardless of the nu mb er of kits used, the m inimu m safe distances for the
M180 cratering k it are 1,200 meters for u np rotected personn el an d150 meters for personnel u nd er overhead cover.
c. Detonation. When firing the M180, use the M34 50-cap blasting m achine.
Section IV. Dem olition A ccessories
1-16. Time Blastin g Fuse. The time blasting fuse transmits a delayed spit of flame to a nonelectricblasting cap. The d elay allows th e soldier to initiate a charge and get to a safe distance before theexplosion. There are two types of fuses: the M700 time fuse and safety fuse. Althou gh safety fuseis not often employed, it is still available.
b. Use. Use detonating cord to p rime and detonate other explosive charges. When thedetonating cord’s explosive core is initiated by a blasting cap, the core will transmit the detonationwav e to an unlimited nu mber of explosive charges. Chapter 2 explains the u se of detonating cordfor these purposes.
c. Precautions. Seal the ends of detonating cord with a waterproof sealant when used to fire
und erwater charges or when charges a re left in place several hours before firing. If left for no longerthan 24 hour s, a 6-inch overlap w ill protect the rema inder of a line from m oisture. Avoid kinks orsharp bends in priming, as they may interrupt or change the direction of detonation and causemisfires. Avoid un intended cross-overs of the d etonating cord w here no explosive connection isintended . To avoid internal cracking d o not step on the d etonating cord.
1-18. Blasting Caps. Blasting caps a re for detonating high explosives. There are two ty pes of blasting caps: electric and nonelectric. They are designed for insertion into cap wells and are alsothe detonating element in certain firing systems and devices. Blasting caps are rated in power,according to the size of their m ain charge. Commercial blasting caps are norm ally Num ber 6 or 8and are for detonating the more sensitive explosives, such as commercial dynamite and tetryl.Special military blasting caps (M6 electric and M7 nonelectric) ensure positive detonation of thegenerally less sensitive military explosives. Their main charge is approximately double that of commercial Num ber 8 blasting caps. Never carry blasting caps loose or in un iform pockets wherethey are subject to shock. Separate blasting caps prop erly. Never store blasting caps w ith otherexplosives. Do not carry blasting caps and other explosives in the sam e truck except in an emergency(paragraph 6-11, page 6-10).
WARNINGHan dle m ilitary and comm ercial blasting caps carefully, as both are
extremely sensitive and may explode if hand led imp roperly.Do n ot tamper w ith b lasting caps. Protect them from shock and extreme heat.
a.Electric Blasting Caps.
Use electric blasting caps when a source of electricity, such as ablasting m achine or a ba ttery, is available. Both m ilitary and comm ercial caps m ay be used .Military caps (Figure 1-14, page 1-6) operate instantan eously. Comm ercial caps m ay op erateinstantaneou sly or have a delay feature. The delay time of commercial caps for military app licationsran ges from 1 to 1.53 seconds. Electric caps have lead w ires of various lengths. The most comm onlead length is 12 feet. Electric caps require 1.5 amperes of power to initiate. The standard-issue cap
is the M6 sp ecial electric blasting cap. TM 43-0001-38 gives ad d itional inform ation on b lastingcaps.
WARNINGDo not remove the short-circuiting shu nt un til ready to test the cap.
Doing this p revents accidental initiation b y static electricity.If the cap has n o shun t, twist the lead’s bare en ds together w ith at least
three 180-degree turn s to provide a sh un ting action.
b. Nonelectric Blasting Caps. Initiate thesecaps with time-blasting fuse, a firing device, ordetonating cord (Figure 1-15). Avoid usingnonelectric blasting caps to p rime u nd erwater
charges because the caps are hard to waterproof.If necessary, waterproof nonelectric blastingcaps with a sealing compound. The M7 specialnonelectric blasting cap is th e stand ard issue.The open end of the M7 special non electricblasting cap is flared to allow easy insertion of the t ime fu se. TM 43-0001-38 gives ad d itionalinformation on blasting caps.
1-19. M lA4 Primin g Ad ap ter. The MIA4priming adapter is a plastic, hexagonal-shapeddevice, threaded to fit threaded cap wells. The
shoulder inside the threaded end will allow time blasting fuse and detonating cord to pass, but theshou lder is too sm all to pass a m ilitary blasting cap. To accomm odate electric blasting caps, theadapter has a lengthwise slot that permits blasting cap lead wires to be quickly and easily installedin the adapter (Figure 1-16).
1-20. M8 Blasting Cap Hold er. The M8blasting cap holder is a m etal clip designedto attach a blasting cap to a sheet explosive(Figure 1-17). These clips are suppliedwith Ml18 sheet demolition charges an dMl86 roll demolition charges. The M8blasting cap h older is also available as aseparate-issue item in quant ities of 4,000.
1-21. Ml D etonating-Cord Clip . TheMl detonating-cord clip is a device for hold ing tw o strand s of detonating cord together, either
parallel or at right angles (Figure 1-18, diagram 1). Using these clips is faster and more efficientthan using knots. Knots, if left for extended p eriods, may loosen and fail to function prop erly.
a. Branch Lines. Connect a detonating cord branch line by p assing it throu gh the trou gh of the Ml detonating cord clip and through the hole in the tongue of the clip. Next, place the line/ ringmain into the tongue of the clip so that it crosses over the branch line at a 90-degree angle and ensure
the crossover is held secure by the tongue; it may be necessary to bend or form the tongue w hiledoing th is. (Figure 1-18, diagram 2, page 1-17).
b. Splices. Splice the end s of detonating cords by first overlapp ing them app roximately 12inches. Then secure each loose end to the other cord by using a clip. Finally, bend the tongu es of the clips firmly over both strands. Make the connection stronger by bending the trough end of the
clip back over the tongue (Figure 1-18, diagr am 3, page 1-17).
1-22. Ml Adhesive Paste. Ml adhesive paste is a sticky, pu tty-like substance that is u sed to attachcharges to flat, overhead or vertical sur faces. Adhesive paste is u seful for hold ing charges w hiletying them in place or, under some conditions, for holding without ties. This paste does not adheresatisfactorily to d irty, du sty, wet, or oily sur faces. Ml adh esive paste becomes useless wh ensoftened by water.
1-23. Pressure-Sensitive Adhesive Tape.
a. Characteristics. Pressure-sensitive tape is replacing Ml ad hesive pa ste. Pressure-sensitivetape has better hold ing prop erties and is more easily and quickly app lied. This tape is coated onboth sides with pressure-sensitive adhesive and requires no solvent or heat to apply. It is availablein 2-inch-wide rolls , 72 yard s long.
b. Use. This tape is effective for holding charges to dry, clean wood, steel, or concrete.
c. Limitations. This tape does not ad here to d irty, wet, oily, or frozen su rfaces.
1-24. Supp lemen tary Adhesive for D emolition Ch arges.
a. Characteristics. Thisadhesive is used to holddemolition charges when thetarget su rface is below freezing,wet, or un derwater. The adhesivecomes in tubes packed inwater-resistant, cardboard slideboxes, with w ooden ap plicators(Figure 1-19).
b. Use. App ly the adhesiveto the target surface and thedemolition block with a woodenapp licator and press the twotogether.
1-25. Waterproof Sealing Comp oun d.This sealant is for w aterp roofing connections between
time blasting fuses or d etonating cords and nonelectric blasting caps. The sealing compou nd willnot make a perman ent waterp roof seal. Since this sealant is not p ermanent, fire und erwaterdemolitions as soon as possible after placing them.
1-26. M2 Cap Crim p er. Use the M2 cap crimper (Figure 1-20) for squeezing the shell of anonelectric blasting cap arou nd a time blasting fuse, standar d coup ling base, or detonating cord .
1-28. Blasting M achin es. Blasting machines provide the electric impulse needed to initiate electric
blasting-cap operations. When operated, the M32 and M34 models use an alternator and a capacitorto energize the circuit.
a. M32 10-Cap Blasting Machine. This small, lightw eight blasting machine (Figure 1-22)produces adequate current to initiate 10 electrical caps connected in series using 500 feet of WD-l
cable. To operate the m achine, use the following p rocedure:(1) Check the m achine for p roper operation. Release the blasting m achine hand le by rotating
the retaining ring downward while pushing in on the handle. The handle will automatically springoutward from the body of the machine.
(2) Activate the machine by dep ressing the hand le rapidly three or four times u ntil the neonindicator lamp flashes. The lamp is located between th e w ire terminal posts and cannot be seenuntil it flashes, since it is covered by green plastic.
(3) Insert the firing wire leads into theterminals by pu shing dow n on each terminalpost and inserting the leads into the metal jaws.
(4) Hold the machine upright (terminalsup ) in either hand, so the plunger end of thehand le rests in the base of the palm an d thefingers gra sp th e machine’s bod y. Be sure tohold the m achine correctly, as the hand les areeasily broken.
(5) Squ eeze the hand grip sh arply severaltimes until the charge fires. Normally, no morethan three or four strokes are required.
b. M34 50-Cap Blasting M achine. Thissmall, lightw eight machine produ ces adequ atecurrent to initiate 50 electrical caps connected ina series. It looks like the M32 blasting machine(Figure 1-22) except for a black ban d aroun d thebase and a steel-reinforced a ctuating han dle.Test and operate the M34 in the same manner as
the M32.
1-29. Firin g Wire an d Reels.
a. Types of Firing Wire. Wire for firing electric charges is available in 200- and 500-foot coils.
The two-condu ctor AWG Nu mber 18 is a plastic-covered o r ru bber-covered wire available in500-foot rolls. This wire is wound on an RL39A reel unit. The single-conductor. AWG Number20 annunciator w ire is available in 200-foot coils and is used to make connections between blastingcaps and firing w ire. The WD- l/ TT commu nication w ire will also work, but it requires a greaterpow er source if more than 500 feet are used (blasting machines will not initiate the full-rated nu mber
of caps connected with mor e than 500 feet of WD-l/ TT wire). As a ru le of thu mb, use 10 less capsthan the m achine’s rating for each add itional 1,000 feet of WD-1/ TT wire employed.
b. Reel. The RL39A reel, with sp ool, accomm od ates 500 feet of wire. The reel has a ha nd leassembly, a crank, an axle, and tw o carrying strap s (Figure 1-23). The fixed end of the wire extendsfrom the spool through a hole in the side of the drum and fastens to two brass thumb-out terminals.
The carrying handles are two U-shaped steel rods. A loop at each end encircles a bearing assemblyto accomm odate the axle. The crank is riveted to one end of the axle, and a cotter p in holds the axlein place on the opp osite end.
1-30. Fir ing D evices an d O ther Accessory Equ ipm ent
a. M60 Weatherproof Fuze Igniter. This device is for igniting timed blasting fuse in all weatherconditions, even un derw ater, if properly w aterproofed. Insert the fuse throu gh a ru bber sealinggromm et and into a split collet. This procedure secures the fuse w hen the end capon the igniter istightened (Figure 1-24, page 1-22). Pulling the pull ring releases the striker assembly, allowing the
firing pin to initiate the primer, igniting the fuse.Chapter 2 (page 2-4) gives detailed operating
instru ctions for the M60 igniter.
b. Demolition Equipment Set. This set (Electric and Nonelectric Explosive InitiatingDemolition Equipment Set) is an assembly of tools necessary for performing demolition operations(Table 1-4, page 1-22).
