AV Geeks 16mm Lunch 7-4-2025

Hi everybody. This is Skip Alzheimer. Welcome to the AV Geeks lunchtime streaming show. We are pre-recorded today because I'm taking the day off goofing off. Uh I don't know what I'm doing, but um yeah. Uh anyways, happy 4th of July. uh whatever that means to you. Um today uh it meant explosions. That's what today was. And uh I'll be showing you three films. Uh one is uh a civil defense film called Fighting the Firebomb, which is what to do in case a firebomb drops inside of your house. Um then explosion danger lurks. Then uh something made for police officers and law enforcement called Bomb Basics. Something that I probably should not be showing you, but it's all about the boom. We like the films, the films that go boom. Um, anyways, uh, everybody have a great holiday and weekend and I'll see you on Monday. Um, if you like what you're watching or you like the idea of what we're doing, hit the thumbs up, hit the like, you can donate via the superthanks button. You can go to kofi.com/abeks or patreon.com/avgeeks. Um, yeah, we'll see you uh on Monday. Take care. Bye. [Music] [Music] War brings the challenge of fire from the skies. The most common type of firebomb is the lightweight magnesium incendiary shown here. Its purpose is simple, to demoralize the people and to overtax the local fire departments and air raid precautions units. One bomber can carry as many as 2,000 firebombs in one load. Enough to start about 150 fires unless each bomb is quickly controlled. The problem seems answerless because professional and auxiliary firemen must be dispatched to only the most serious fires. This is where you are needed to protect yourself, your family, your home and community. The answer lies in your hands. Firebombs are dangerous, but you can control them effectively and with reasonable safety. And here's how. First, the bomb itself, 14 in long by 2 in in diameter and weighing approximately 2 lb, falls nose downward, guided by its tail fins. The body of the bomb is a shell or tube of magnesium with walls about 1/2 in thick. Backed in the center of the shell is thermos and at one end of the shell is a starting mechanism. In its downward flight, the bomb gathers sufficient speed so that its impact forces the firing pin into a percussion cap which ignites a starting mixture. This in turn ignites the thermite compound which fills the core of the bomb. So violent and intense is the thermit reaction that it sprays flaming metal over a considerable area. Stay clear of the bomb during this violent period to avoid being splattered by burning sparks of molten metal. Thermit consists of iron oxide and granular aluminum. All burning requires oxygen. In thermmit, the iron oxide is able to supply oxygen to help the aluminum to burn. Because the thermmit carries its own oxygen supply, there is no way to extinguish it by smothering and no way to extinguish it by cooling below the burning point because it burns at the extremely high temperature of 4500° F, yielding molten iron and aluminum oxide. The purpose of the therm is to burn hotly enough to light the magnesium shell, which will now burn intensely for 10 to 20 minutes, during which time it will start a serious fire if left unattended. Magnesium like the aluminum and thermmit must have oxygen to burn. But unlike thermmit which contains its own supply, magnesium must obtain oxygen from the air or elsewhere. If somehow the air supply could be cut down, we would be able to cut down the burning of the bomb. One way to do this is by using sand. Take this example for instance. A bomb has fallen into the attic. The violet the reaction has finished. The magnesium is burning, but the fire has not spread. So, a shovel and a pale of sand are brought up. Pouring most of the sand onto the floor, we start to work. First, shoveling sand over the bomb. This covering of sand makes it more difficult for air to reach the bomb. Thus, though sand will not extinguish the bomb, it will slow up its burning and cut down the heat radiated from it. Notice how close to the bomb the operator can work under these circumstances. Since burning magnesium actually reacts with the sand, the bomb does not long stay completely covered, but erupts through the sand blanket much like a seathing volcano. A few inches of sand are placed in the bottom of the pale so that the bomb will not burn through and carried out. Then the bomb and sand covering are scooped up with a flat-nosed shovel and dumped into the pale. You can see how important the straight edge on the front of the shovel is in making a clean job of scraping up the bomb. After covering the bomb in the pale with more sand, any traces of molten burning magnesium or burning wood embers left on the floor are extinguished with water spray from a watertype extinguisher. And then thrusting the handle of the shovel through the pale handle, which by now is too hot to touch, the pale bomb and all is carried downstairs to be dumped outside where it can do no harm. Surprising but true, is the fact that water, which puts out ordinary fires, acts as fuel for burning magnesium, speeding up the process of combustion. Oxygen is considerably more concentrated in water than in air, and the burning magnesium is able to decompose water and extract oxygen from it to support its burning. A solid stream of water applied to burning magnesium causes a dangerously explosive reaction. The solid stream forces water into pockets of molten magnesium, forming steam of tremendous pressure, which shoots out, spraying burning magnesium in all directions. On the other hand, water applied in the form of a coarse spray is the best method of handling magnesium bombs. The spray speeds up the burning of the magnesium, reducing the life of the bomb to about 2 minutes and wetting down the surroundings, thus restricting the spread of the fire. The lighter weight of the spray keeps the water on the surface of the molten magnesium, and steam is dissipated without the explosive effect caused by a solid stream of water. Perhaps the simplest and most common device for producing a water spray is a garden hose long enough to reach the remote or top floor. It should have the usual adjustable nozzle which can be changed from a spray for the bomb to a solid stream for extinguishing fires that have spread in the surroundings. But there always remains the danger that water pressure may fail in a crucial moment during an air raid. Water manes may have been bombed or fire apparatus nearby may be draining and lowering the pressure in your locality. So, don't count solely on a garden hose. Another convenient source of water with self-contained pressure to produce an effective stream or spray is the standard soda acid extinguisher, which is turned upside down for use on fires and held that way by the bottom handle, so long as water pressure is desired. In this instance, we have the most probable situation. As you arrive on the scene, the fire is spreading fast in materials close to the bomb. Using a solid stream, control this fire first. Then, breaking the stream with your thumb partially over the nozzle, create a coarse spray, which is correct for use on the bomb itself, keeping a watchful eye, of course, for any flaring up of the surroundings. To completely extinguish a fire bomb, and to bring the average blaze, which is spread from the bomb, under control, two extinguishers are desirable. And now, a second one is brought in to finish the job. Embers left to smolder are dangerous, so avoid any later flare up by assuring yourself that none remain. All other watertype extinguishers, loaded stream, gas cartridge, or foam are suitable for use on magnesium bombs. Here is a foam extinguisher. Starting off with a spray for safety to avoid a possible explosive reaction, the foam is directed at the bomb, which in this case has fallen onto a concrete garage floor. After the foam blanket has started to build up around the bomb, it is safe to change to the stream. Gradually, the foam builds a blanket over the top of the burning bomb, while the water in the burning magnesium beneath and speeds up the fire. Occasionally, the bomb will burst through craters, but for the most part, the foam blanket serves to cut down the heat and glare. Finish off the bomb with another foam extinguisher or any other convenient water spray source. Only water- fil or water solution types of chemical extinguishers are recommended for use on magnesium incendiary bombs themselves. All other fire extinguishers will perform the same effective service on fires started by incendiaries as they always have on fires started from other causes, but they are not effective on magnesium. If you arrive before the thermmit reaction is finished, take cover until it is over to avoid the danger from spurts of burning thermit or a possible explosive charge which would reveal itself during this initial period. Has settled down to simply burning magnesium. Go to work with a solid stream first which is spread from the bomb. then switch over to spray on the bomb itself. Used here is a device called the pump tank which carries a supply of water that is forced out through its hose by pressure from the hand operated pump. This is a particularly clear illustration of the manner in which the water spray wets down the area surrounding the bomb as the bomb itself is being rapidly consumed. The pump tank may be equipped with hose longer than the standard length, which gives it the only practical feature of the English stirrup pump. The long hose aids in fighting incendiaries out on roofs and up an attic locks, where to carry anything but a hose would be difficult. With the long hose, of course, the device will require additional manpower. A second man pumps while the hose operator gives his attention first to the fire resulting from the bomb using the solid water stream. There's no point in spraying the bomb first while the house burns down around you. So bring the spreading fire under control to start with. Then give the bomb the works. Incidentally, you'll notice that the further you put your thumb over the nozzle, the finer the spray. too fine a spray fails to feed enough water to sufficiently accelerate the rate of burning of the bomb. And it is this cutting down of the total burning time that makes water so desirable a method of incendiary control. A third man is necessary to refill the pump tank before it's empty so that the pumper can maintain a steady pressure of water for the hose operator. This third person also keeps a watch in other parts of the house for any spread of fire or other fire bombs. He refills his fail from whatever water supply is available. Of course, if a sudden flare up of the fire occurs, it is wise to shift from the bomb for a moment to bring the spreading fire under control. But the sooner the bomb is out, the better. So get it out of the way as quickly as possible and then see all traces of the fire that may be burning or smoldering are put out. Tests have shown that certain thicknesses of roughing materials will resist penetration and they are shown here. Most home roofs are not this strongly constructed. Hence, it is expected that if an incendiary bomb crashes through, the bomb will come to rest on the upper floor. The attic with our air raid warden. Like most attics, it is cluttered up with as fine an assortment of fuel as any incendiary bomb could desire. Though out with the clothes and other things which are removable and which might catch on fire easily. A few back issues of magazines at the wrong time could help to make your house more than a back issue. They go too. And let's clear out the dollhouse attic, including the dollhouse itself. Clearing the attic will reduce the danger of fast spreading fire there, but a bomb may still burn through and penetrate the ceiling of the room below. Then you will have to put out fires on both floors. So, if your local building department approves, some protection against burning through attic floor by laying overlapping rows of building paper and then by spreading a layer of 2 in of dry sand. Over the sand, place wooden frames with chicken wire stretched over them four to 6 in above the sand so that it will break the fall of the bomb and prevent it from scattering the sand. Keep equipment accessible, ready for instant action. Fire extinguishers should be kept properly mounted for easy access and inspected and recharged regularly. It's easy to keep a supply of sand and shovels on hand and pump tanks should be kept filled with water and in the Watts organization has been unceasing in its effort to promote safety demonstrating the seriousness of hot water overheating explosions. As early as 1939, various tests and overheating demonstrations were held, and several hundred representatives of the plumbing industry witnessed hot water tanks actually exploding. Heat. Heat. Heat. Heat. Explosion danger lurks in thousands of typical hot water heater installations because the great majority have either improper protection or no protection at all. It's hard to realize that an overheated tank can be dangerous, but 30 gallons of superheated water can explode with violence, causing destruction. Destruction. [Music] One person was killed and 10 hurt in this tenement house explosion. It cost nearly $10,000 to rebuild this house after a gas hot water heater exploded. This was a clubhouse completely demolished by an explosion of an 80-gal electric water heater. No protection whatever. Now look at this. The tank went right up through the bathroom and stuck in the ceiling. Many of these tank explosions caused only property damage, but it is lucky more people haven't been fatally hurt. An ordinary heater exploded in this cafe and blew the front right out on the sidewalk. This apartment house suffered heavily from a tank blast. In order to witness the effects of an explosion happening in a home, Watts built model houses and caused an overheated 30-gal tank inside to rupture. Cameramen record the tremendous force and resulting damage. Watch it go. The tank landed over 500 ft away. A bomb could not do a better job of destruction. Notice the barricade and pit in the foreground which protected the engineers from flying debris and parts of the tank. to carry out further field test field and connected to a water supply. As the tanks are being heated, barricade and pit enable safe observation through this periscope. A thermouple in the tank is connected to this temperature recorder which gives accurate readings of the rising water temperature tabulated at frequent intervals for complete engineering data. Later, a water hammer condition was created in the tank which caused the shell to rupture at a predetermined time. When the superheated water reached 300°, here's what happened. And the engineers almost got a steam bath from this explosion. It is obvious that temperature must be controlled to asssure safety in hot water tanks. To continue this experiment in the field, a heavyduty tank is set up and heated by a gas heater. A pressure relief valve on the water supply line is dripping steadily at 75 pounds, taking care of the thermal expansion of the water. But the temperature continues to rise and when it reaches 302°, cameramen spotted at strategic points are alerted for action. The superheated water is subjected to a hydraulic water hammer. Notice steam escaping from the bottom. Suddenly, it ruptures and blows off the bottom head. As the tank explodes, the copper tubing and control lines are ripped up into the air with the tank. These slow motion pictures show the rocket effect of the explosion caused by the superheated water generating steam pressure energy which propelled the tank several hundred ft in the air. There it comes down. And here it is. In spite of the plane pressure relief valve maintaining normal pressure, this tank exploded. To demonstrate the effects of excessively high pressure with low temperature, this hydraulic hand pump is increasing normal pressure in an extra heavy tank. Now the pressure is nearly 300 lb. Still going strong at 400 lb. At 500 lb per square inch, there is over 1 million pounds total pressure pushing against the entire inner surface of this tank, but we're not afraid of it. And step right up to the tank with a pointed hammer and wham! Did you get wet? We did, but no explosion because no heat energy to release, just pressure. To explain the behavior of water above atmospheric boiling point, this chart shows the comparative boiling points at various pressures. These are standard physical factors. The higher the pressure, the higher the boiling point. Atmospheric pressure at sea level is zero gauge, at which point water boils at 212° F. As in this open beaker, no matter how much heat is added, the temperature cannot rise above 212°. The water boils and changes to steam, passing off into the atmosphere. But under pressure, more heat is absorbed by water before it boils. For example, at 30 lb pressure, water will not boil until temperature reaches 274°. At 60 lb pressure, water boils at 307°. But when a 30-galon tank explodes at 297° with 50 lb pressure, it liberates over 2 million foot-lbs of energy or more than that released by 2 lb of dynamite. In this glass tank, we will illustrate another serious hazard of overheated water which is common to open main systems. When the superheated water starts to boil, steam forms and displaces the water, forcing it back into the cold water supply line. As the volume of steam increases, it overcomes the water main pressure and pushes this boiling water further and further back. Should a cold water outlet be opened, this steaming water can cause personal injury and also toilet closet breakage from sudden high temperature. This is also what causes burned out meters. However, of greater importance, if a tank ruptured due to heat weakening and corrosion, this superheated steam and water when liberated to atmosphere would explode with tremendous violence. If all the water is forced out of the tank, something has to give way eventually. Now we install a temperature relief valve in the hot water outlet and record temperature in the top of the tank with this thermometer. When the water temperature in the tank reaches 212°, the fully automatic temperature relief valve begins to operate. Steam and the thermometer on the drain outlet show that hot water is escaping through the relief valve and the thermometer shows a drop of the water temperature in the tank as cold water replaces the hot water. Therefore, to prevent explosions and overheating hazards, install combination temperature and pressure relief valves so as to discharge the hottest water from the top of a tank. Watts has conducted several explosion demonstrations publicly which were carried out the same as factory field test demonstrations described earlier in this film. Tanks and equipment were placed in an open field for observers to watch. Startled cameramen managed to catch these after effects when two steel tanks exploded ahead of schedule at unusually low temperatures. When explosions in actual service do occur, they happen just this way. In this small cabin, a 30-galon copper tank exploded when a water hammer condition was created, causing the shell to rupture and tear off the upper half. Another camera shot of the explosion shows where the upper half went. It was propelled to a height which observers estimated to be 400 ft and landed 450 ft away. Here's the top part of the copper tank. Flashing superheated water caused this not pressure. To summarize, excessive pressure relief protection alone cannot prevent overheating hazards or lower the water temperature. And only water temperature above atmospheric boiling point has the energy to cause explosions and overheating hazards. Scenes of destruction from hot water explosions like this one in a basement and this one of a factory serve to remind that water when superheated isn't just water. It's a latent destructive power which when released to the atmosphere by rupture is like a bomb causing damage and destruction to property and injury to people. Therefore, as many cities have done, it is very essential that safety measures be adopted to require proper temperature and pressure relief protection for public safety. [Music] Explosives, a tool of man, one of the potent forces to enrich his present and future. Without its intelligent use, much of our modern technology would not be in existence, such as the strip mining of copper, iron, and other metal ores. Its use in oil well drilling and coal mining, the moving of hills and mountains for our great highways and railways, to be used for building power stations for our comfort in the form of heat and light. However, like many useful tools beneficial to mankind, when this great force is placed in the hands of persons bent on destroying society, mankind is threatened. [Music] [Music] Extreme [Music] security measures have been imposed at all San Francisco police stations, including Southern Station at the Hall of Justice after Monday night's bombing at Park Station. Nine officers suffered injuries of varying severity when a thunderous blast sprayed inchlong metal staples throughout the small station office like machine gun bullets. The staples riddled the interior walls and shredded pages of the station log. As workmen began temporary repairs and the damage was being estimated, Mayor Aliotto came to Park Station to view the wreckage. He examined the office and the window sill where the bomb was planted just prior to the 11 p.m. shift change. Before going to San Francisco General Hospital to visit the injured officers, Aliota offered a $5,000 reward for the bomber. And he spoke of the kind of person or persons who could have done such a deed. And we don't know the nature of the people involved in this thing, but the but the uh as I say the relationship between this and the Berkeley police episode would indicate that there is uh some connection between the two. We are going to have a very very vigorous investigation going to be an all-out investigation to bring these kind of maniacs to justice. We'll get them there. [Applause] [Music] Even in death, the warp mind finds excitement. Just prior to commencing the funeral processional of a fallen San Francisco police officer, a device exploded at the entryway to St. Brendan's Church. Fortunately, the mourners and those paying their last respects had not started to enter the church, and no one was seriously injured in this explosion. I'm not blaming anyone in particular. I merely ask the people of San Francisco to become involved with us, to help us to do the job we are supposed to do, to help us protect lives and property in San Francisco. Sure, we're in the line of business where some of us get killed, but that doesn't mean that there should be a general amnesty and holiday for those who kill policemen. We don't know what they tape. It might be a collection of it. [Music] [Music] [Applause] [Music] With today's attitudes toward the establishment, whether it's the police, or private industry. It is imperative that security personnel be fully acquainted with the potential of explosive devices that are being used against society. [Music] Experience has clearly demonstrated that bomb threats are being directed at a wide range of public and private facilities in the United States, such as banking firms, colleges across the land, airlines, gas and power companies, and even our railroads, though not as widely publicized, come in for their dubious share of threats and actual bombings. Fortunately, in many cases, the facility chosen for this bizarre action is forewarned by a phone message from the perpetrator who, for any number of reasons, such as blackmail, publicity for a misguided cause, or especially if the bomber wishes to avoid injuries or death, reveals information that a bomb has been placed and in fact will relate when and where it will detonate. The natural reaction of an untrained person upon receiving a threat regarding a bomb is panic. A properly trained individual, however, will remain calm and take full advantage of the situation to improve the likelihood that the incident will be safely and effectively handled. An accurate analysis of the telephone threat can provide much information for the subsequent investigation. For example, the collar could reveal personal characteristics such as sex, ethnic or national group origin, or mental state. In any event, it may be necessary to train all personnel to respond properly to telephone threats and by utilizing a bomb threat checklist with such specific questions as exact location of the bomb, time set for detonation, what does it look like, what is the explosive, why was it placed. This information can set the stage for successfully thwarting the bomber. Remember, the initial contact can and has saved many lives and avoided much property damage. Once the bomb threat has been received, immediate action must be taken to analyze the threat and appropriate responsive steps instituted by someone of decision-making authority. Usually, this position is assigned to a ranking security officer who alerts management, notifies law enforcement or public safety agencies, mobilizes search personnel, and sets up a command center normally comprised of a mobile radio unit placed in the area of search. In cases where a bomb search is to be made or is in progress, fire and medical teams and their equipment should be on a standby basis outside of a 300 ft evacuation radius. By moving with the search and maintaining communications, the command center is able to have constant contact with all phases of the search and related operations, thereby asserting close supervision and control over search personnel and their actions. By following this procedure, the command unit can in the event of actual detonation of a device immediately call for medical and fire equipment to handle any resulting casualties or fires caused by the explosion. Search personnel must be given special training in systematic search procedures and to the extent possible bomb recognition. Their training should emphasize their roles as searchers and not bomb experts. Search personnel must constantly be aware of the great risk involved in touching or moving any suspected explosive device. The use of common sense or logic in searching has both advantages and limitations. Searchers should never rely exclusively on random or spot-checking of only logical bomb locations as the bomber may not behave in a logical manner. The proof of this is of course the fact that a bomb is being used in the first place. Immediately upon locating an item suspected of being a bomb, search personnel must notify the command post. In no case should untrained search personnel attempt to touch or move a suspected device. The location of one bomb or suspicious object should not terminate the search. It's not unusual for bombers to plant multiple bombs in an effort to ensure success, or if nothing else, to cause death or injury to personnel processing the bomb scene. On one occasion, as many as 52 individual bombs were found in one target area. Also, to delay the search while a suspicious object is checked out may result in unnecessary risk to life and property, especially in those cases involving a clockwork fuse, which is steadily approaching detonation time. [Music] Hey, hey, hey. Almost any means which man has devised as an aid to monitor his time, whether in recreation or labor, can be and has been used to destroy either man or his endeavors. The common time piece, a wristwatch or an alarm clock, has been used for the purpose of destruction, either by directly initiating the explosive or as in many cases, activation of an anti-disturbance device after it has been placed, allowing the perpetrator to safely make his escape. Assume for a moment that this common mercury switch component has been activated by a clock and is being used as a triggering device in a bomb. It is known as a tilt switch and is very simple. A small glass vial with one or two wires protruding through one end making up an open circuit. Contained in the vial is a small amount of liquid mercury. All one has to do is to move it suddenly or tilt it. The circuit closes and Another type of anti-disturbance device is this cute little do-it-yourself number. This is known as a vibrator or trembler switch. Very simple, but exceedingly deadly. The slightest movement causes detonation. As example, I'll blow on it. [Music] To illustrate just how simple a triggering device can be, even to the point of being ludicrous, I show as evidence a common household item. Close pin. Here is an excellent example of a harmless close pin being utilized as a pressure release triggering circuit. Pressure release [Music] Then we come to the electrical solenoid used for a collapsing circuit. This is perhaps one of the most dangerous circuits of the entire electrical group next to a tremler or vibratory switch. After the battery power drains away, the relay closes, firing the circuit. Or should any one of the wires be cut, collapse the circuit, and detonate the bomb. I'm sure you've all seen in the movies or on TV the bomb expert casually reach in and with a knife or a pair of side cutters sever a wire thereby rendering the bomb safe. All I can say is lots of luck. Should anyone come across a device that is alleged to be a bomb and any wires of any type visible, do not under any circumstances touch, tamper with, or above all cut a wire. Or if you should, this could happen to you. This item has been used a great deal in the past and no doubt will be utilized in the future. The concept is simple. The effects devastating. The components are readily available to anyone, anywhere. It's small enough to be easily carried and concealed, yet large enough to contain a considerable amount of black powder or other explosive. Note the burned out time fuse extending from one end of the bomb. The unwary, assuming this is a dud, reaches down, picks it up, and meets his maker. This particular pipe bomb has achieved just what it was intended to do. blow up in someone's hand. It has been called a Texas or Algerian bomb and is primarily an anti-personnel device. This bomb not only contains the explosive compound, but in addition, a power source, an arming device, and a tilt switch. A most fish device. And this type of fuse has been used extensively in the past in pipe bombs that have gone off or been disarmed before they've exploded. There are a number of manufacturers of fuses like this. They're hard to trace, but like other situations, the type of fuse can add total information patterns to a broader background of methods of operations of materials or assemblies found at other locations. A burning tank fuse like this will set black powder off directly, but it won't ordinarily set off commercial explosives. [Applause] Now for commercial explosives, time fuse is used to set off the blasting cap which in turn sets off the detonation or an electrically detonated blasting cap is used without time fusing. Although in this case, timing can be controlled by a simple clock mechanism. A black powder itself is a common chemical compound. It's categorized as a low velocity explosive and it's extremely dangerous. It'll detonate from heat, shock, or friction. It's been used quite extensively in the manufacturer of clandestine devices and it's well-known substance. So the can at the end of the fuse is one pound of black powder. People tend to look upon it and handle it too casually. They don't give black powder the caution it demands. The confined expanding gases build to high pressures and tear apart the container and anything around it. And so from a little sulfur, some potassium nitrate, and an amount of carbon come bombs. Also, property destruction and loss of life. Here are some components common to a pipe bomb, an easily obtained nipple, couple of end caps, a small hole, and a piece of time fuse. Pipe bombs often use black powder and a number of people have blown themselves up making such devices. The black powder pipe bomb is unstable and a few grains on the threads could cause detonation. Remember bombs show no allegiance even to their creators. But there are many other explosive materials and devices that are appearing now. more sophisticated devices, higher range explosives, and more exotic triggering mechanisms. These higher range explosives are commercially manufactured and are widely used in construction, logging, and similar operations. The reports come in every day. 19 sticks of 40% dynamite stolen. 13 bags of 20 lb nitrocarbon nitrates stolen. Dynamite is in the high explosive category. It's nitroglycerin absorbed in a binder of one kind or another. In addition to the problem of its use in an explosive device, we're up against another problem. Dynamite is one of the more hazardous commercially manufactured explosives because it deteriorates quite rapidly when not cared for or stored properly. Put the two circumstances together. dynamite stolen and hidden, uncared for by inexperienced and irresponsible people and the inherent deterioration characteristics of the material itself. The point is that if dynamite shows up anywhere, whether it be found by an individual or the police or industrial security forces, and if it's been left in a building or buried in a field, don't touch it. Stay away from it and don't go near it until trained demolition personnel get there. Dynamite, if it's not given enough attention, is like a woman. Almost anything will cause it to blow up. So, the dynamite, most likely to appear from clandestine sources, can easily be in bad condition. It may also have been improperly stored for long periods of time. It could look like this with nitroglycerin crystals and evidence that are extremely sensitive to heat, shock, and friction. And in this form, the dynamite could detonate for no apparent reason. And once again, the admonition, don't touch it until trained demolition personnel are present. Dynamite is usually used in stick form without confinement. It's at the low end of the high explosive range. And dynamite or for that matter any of the class of high explosives need no confinement. Dynamite explodes at a velocity between 7 and 21,000 ft per second. A few months ago, San Francisco police officers answered a call for assistance and almost lost their lives. An explosive device was waiting for them at 1529 Hudson Street when they arrived. It was secreted under the front porch. Well, there's nothing that can be said. It's just a feeling that we had when we got here. The things didn't look right, so we went around and in the rear door instead of the front door because of the circumstances at the time we was here. The blast uh apparently uh uh was right close to almost all eight of the men. Yes, we had uh three men inside the building, a couple out back, and the others were in the front coming up the front steps when the blast took place. This apparently was a phony call, of course, but uh this was not the first one tonight. No, there had been an earlier call early this evening and apparently the officers didn't get a chance to respond into the building for some reason that we don't know. Perhaps the same caution that you used. I hope so. Do you happen to know, Sergeant, what triggered the device at all? As far as I know from the bomb squad, it was triggered by a uh wire that came through the door and to the bomb with some kind of a firing device at the bottom intended to detonate whenever the door was opened. Yes, it was a spring type, I imagine. So, they presumed, I gather, that uh someone would enter through the front door and that's when they'd get it. Yeah, the bomb was set up definitely to go off when somebody opened the door from the front. Dynamite is used a lot. In fact, black powder and dynamite account for a large percentage of explosive devices, bombs that are being used. Other materials are coming into wider use though, TNT, C4, and detonating cord. The military explosives are appearing in more sophisticated devices. But dynamite, because of its availability, is the most used in the high explosive class. Vehicles are especially especially vulnerable to explosive devices. They can be put in with just the timing mechanism, a battery and cap, or what is quite a common method, a bundle placed into the engine compartment against the firewall and wired into the ignition coil to trigger an electrical blasting cap on the sticks. Turning on the ignition starts the sequence. Security vehicles should all have hood locks. or at the very minimum should be taped to show if it has been tampered with. This is 40% dynamite. Seven sticks. How much time does it take to place something like this? Well, with the thing pre-made and wired with alligator clips, it doesn't take long. What'll happen when the ignition switch is turned on? We've wired the vehicle's ignition switch to this remote location. The gases from this dynamite explosion were created in 110,000 of a second. Also, pressures near 700 tons per square in were formed at the point of detonation. Dynamite with its characteristic gray white smoke shows a lot of bulging but not too much ripping or tearing. Now compare this with dynamite. This car is a onepound block of TNT and the explosion compared with dynamite is much more shattering. It's primarily a military explosive and not quite as available as dynamite. We're moving up the scale of high explosives, each higher in velocity of detonation and each more shattering. It's used as a main charge in military ordinance, artillery rounds, and that type of thing. Its detonation is too shattering for commercial use generally. Take quarry work for instance. To move a quantity of earth or rock, a lower velocity explosive like dynamite is much better. Use TNT and you'll end up with a pile of sand and gravel. It's not generally used in underground mining operations because on detonation it emits toxic fumes. TNT detonates at about 25,000 ft per second compared to dynamite at about 7 to 21,000 ft per second. At an even higher velocity than TNT is C4. Again, more shattering. A 1 and a/4lb block was used in this vehicle. C4 is a military explosive and has little commercial value. It was used in World War II and called C2. It was then improved for the Korean War and called C3. However, it had an oily consistency intended to break apart. Now, it's composition 4. Except for a slight odor, it looks and feels exactly like kids play-doh. This is the notorious plastic explosive. And I repeat, it has very little commercial value, but it has been appearing in clandestine devices. Numerous items involving C4 have been found using materials stolen from the military areas or even shipped back in the mails from Vietnam. It's stable and yet it's pliable, but it's still an explosive and it can be used with the proper detonators. C4 will withstand a wide variety of temperature changes without detonating. It'll burn with a very hot flame and if contained while burning will most likely detonate. C4 is unusually stable and doesn't deteriorate during storage, even under fairly adverse conditions. C4 has a certain mystique about it. It's relatively new, has certain advantages over other explosives, and it's unusually safe to handle. Now, like most military explosives, C4 has to be bullet impact rated. one stray round into a truck in a battle situation and an awful lot of trucks should be lost. C4 tends to be sticky and that's another of its useful properties. This is an interesting material detonating cord commonly known as debt cord which contains an explosive called penta erthrite tetra nitrate or commonly known as pent for short. Pin makes up the core of the cord or center. The velocity rating of the cord is based on the number of grains of pin per foot. Detonating cord is also known as primacord, trimex, detaacord, sometimes detonating fused and some others. Depending on the diameter of the cord, it comes in spools of anywhere from 100 to 1,000 ft. The outer layer of detonating cord consists primarily of an interwoven plastic fiber material. Compare this with Timefuse, which usually has a waxy, waterproof outer surface. Detonating cord on the outside looks a lot like plastic insulated wire and can readily be mistaken for it. It could also resemble a piece of ordinary clothes line. It's used quite widely in commercial mining operations as well as many other uses. It's also been found in many bombs throughout the United States. Detonating cord like C4 is very resistant to shock. You can bend it, twist it, you can even tie it in knots. So what does dead cord do? Well, in some military uses and in some construction purposes, it's used to trigger a series of charges at for all practical purposes, the same instant within a matter of milliseconds. There's 30 ft of dead cord out there. The plastic bags contain flour and represent TNT. The whole rig could be snaked along a ground or along a building just as well. 5 miles a second from San Francisco to New York in 10 minutes. With detonating cord, you have a relatively safe explosive in linear form that gives it a number of specialized uses in addition to the triggering of other explosives. It's uncomplicated and the blasting cap will set it off. So, what do we have? Pipe bombs coiled inside the pipe. Detonating cord creates a violent explosion with high fragmentation. And from detonating cord, we may get a few other things. We may get a few explosive and incendiary combinations like a little gasoline and a little dead cord and a small timing device. There are any number of things that might crop up, especially where flammable materials such as butane or natural gas or gasoline are stored. The problems of misdirected use of explosives and incendiaries is a tough one because so many of these materials in everyday use have these potentials. So there is a relationship between some incendiary devices and explosives. Ordinarily with high velocity explosives, there is charring but no fire from the detonation itself unless gas lines are ruptured or there is a severe electrical short or an explosive is detonated near flammable materials such as propane tanks or gasoline storage areas with containers like this or even large metal drums or tanks. There are other simply made incendiary devices that are used for ignition of fires only without any actual explosion. Although there may be a very small explosive reaction to obtain ignition, if we put together some sulfuric acid and some potassium chlorate in the proper way and then attach a bottle of gasoline to it, the homebrew incendiary is readily at hand when the same situation extends to some do-it-yourself explosives. Without resorting to commercial or military explosions, the potential is there. It's spring. A beautiful day for gardening. So, a trip to the local friendly garden supply store for a sack of one of the many fast green and fast grow fertilizers. But if your concern is not with growing, but with destroying, how about a stop at Jolly John's fuel farm to gas the car with maybe a small jug of diesel fuel on the side. [Music] And so we have a sack of 80% ammonium nitrate fertilizer in a container of diesel fuel. And if we mix the two in the proper proportion, at this point there's only the potential of an explosion. Heat or normal shock won't set it off. But if we place the mixture against this building and if we add a few triggering elements, [Music] ammonium nitrate and fuel oil, these were the materials used at the University of Wisconsin a few years ago. A panel truck with 1,500 lb of ammonium nitrate mixed with fuel oil and laced with detonating cord. And then the truck was simply parked next to the computer center building. The materials aren't widely used by dissident groups because of the quantities necessary for a large explosion. But if the quantities are there, the material will produce one hell of a blast. [Music] These are a few of the most common devices that are being used. The pipe bomb with a high explosive, say dynamite, TNT or C4. There are many variations in the basic devices and the methods of packaging. a paper sack or a briefcase or possibly an attese case or even a hollowedout book. These are not far out examples. They're actual samples and they're appearing every day and getting more and more sophisticated. It's only logical that this will continue. A few years ago, we founded the people constructing these devices were blowing themselves up. There hasn't been much of that lately, but there has been an increasing number of devices. The capacity of man to learn new technologies is great. But even now, the most common bomb is a clock, a battery, and a blasting cap with a chunk of plastic, TNT, dynamite, or even black powder in a pipe. Yes, dear. I will, dear. Of course I will. Yes, dear. Of course I do. Haley's made these same rounds the last three months. He's conscientious, alert, and very reliable. But he's got a habit pattern. From that it's become relatively simple to we have but scratched the surface in our effort to make those of you responsible for the protection of our way of life a little more knowledgeable when confronted by an explosive item. There are no real experts in this field. For we learn a little more each day. And the greatest mistake one can make is to underestimate the ingenuity of those seeking the downfall of our society. For if you do, you will pay the supreme sacrifice. Your life and perhaps the lives of others.