4.31 FUSE DELAYS -------------------- It is extremely simple to delay explosive devices that employ fuses for ignition. Perhaps the simplest way to do so is with a cigarette. An average cigarette burns for about 8 minutes. The higher the "tar" and nicotine rating, the slower the cigarette burns. Low "tar" and nicotine cigarettes burn quicker than the higher "tar" and nicotine cigarettes, but they are also less likely to go out if left unattended, i.e. not smoked. Depending on the wind or draft in a given place, a high "tar" cigarette is better for delaying the ignition of a fuse, but there must be enough wind or draft to give the cigarette enough oxygen to burn. People who use cigarettes for the purpose of delaying fuses will often test the cigarettes that they plan to use in advance to make sure they stay lit and to see how long it will burn. Once a cigarettes burn rate is determined, it is a simple matter of carefully putting a hole all the way through a cigarette with a toothpick at the point desired, and pushing the fuse for a device in the hole formed. |=| |=| ---------- filter |=| | | | | |o| ---------- hole for fuse cigarette ------------ | | | | | | | | | | | | | | | | | | |_| ---------- light this end A similar type of device can be make from powdered charcoal and a sheet of paper. Simply roll the sheet of paper into a thin tube, and fill it with powdered charcoal. Punch a hole in it at the desired location, and insert a fuse. Both ends must be glued closed, and one end of the delay must be doused with lighter fluid before it is lit. Or, a small charge of gunpowder mixed with powdered charcoal could conceivably used for igniting such a delay. A chain of charcoal briquettes can be used as a delay by merely lining up a few bricks of charcoal so that they touch each other, end on end, and lighting the first brick. Incense, which can be purchased at almost any novelty or party supply store, can also be used as a fairly reliable delay. By wrapping the fuse about the end of an incense stick, delays of up to 1/2 an hour are possible. Finally, it is possible to make a relatively slow-burning fuse in the home. By dissolving about one teaspoon of black powder in about 1/4 a cup of boiling water, and, while it is still hot, soaking in it a long piece of all cotton string, a slow-burning fuse can be made. After the soaked string dries, it must then be tied to the fuse of an explosive device. Sometimes, the end of the slow burning fuse that meets the normal fuse has a charge of black powder or gunpowder at the intersection point to insure ignition, since the slow-burning fuse does not burn at a very high temperature. A similar type of slow fuse can be made by taking the above mixture of boiling water and black powder and pouring it on a long piece of toilet paper. The wet toilet paper is then gently twisted up so that it resembles a firecracker fuse, and is allowed to dry. SLOW BURNING FUSE ~~~~~~~~~~~~~~~~~ (approx. 2 inches per minute) Materials needed: - Cotton string or 3 shoelaces - Potassium Nitrate or Potassium Chlorate - Granulated sugar Procedure: ---------- - Wash the cotton string or showlaces in HOT soapy water, then rinse with fresh water - Mix the following together in a glass bowl: 1 part potassium nitrate or potassium chlorate 1 part granulated sugar 2 parts hot water - Soak strings or shoelaces in this solution - Twist/braid 3 strands together and allow them to dry - Check the burn rate to see how long it actually takes!! FAST BURNING FUSE ~~~~~~~~~~~~~~~~~ (40 inches per minute) Materials needed: ----------------- -Soft cotton string -fine black powder (empty a few shotgun shells!) -shallow dish or pan Procedure: ---------- - moisten powder to form a paste - twist/braid 3 strands of cotton together - rub paste into string and allow to dry - Check the burn rate!! Under water igniters -------------------- Materials needed: -Pack of 10 silicon diodes (available at Radio Shack. you will know you got the right ones if they are very, very small glass objects!) -Pack of matches -1 candle Procedure: ---------- - Light the candle and allow a pool of molten wax to form in the top. - Take a single match and hold the glass part of a single diode against the head. Bend the diode pins around the matchhead so that one wraps in an upward direction and thensticks out to the side. Do the same with the other wire, but in a downward direction. The diodes should now be hugging the matchhead, but its wires MUST NOT TOUCH EACH OTHER! - Dip the matchhead in wax to give it a water-proof coat. These work underwater - repeat to make as many as you want How to use them: ---------------- When these little dudes are hooked across a 6v battery, the diode reaches what is called breakdown voltage. When most electrical components reach this voltage, they usually produce great amounts of heat and light, while quickly melting into a little blob. This heat is enough to ignite a matchhead. These are recommended for use underwater, where most other igniters refuse to work. ENJOY! Delay Igniter from a Cigarette ------------------------------ A simple and economical (everyone wants to save money haha) time delay can be made with a common cigarette. Materials Required: ------------------ Cigarette Paper match String (shoelace or similar cord) Fuse cord (improvised or commercial) Procedure: --------- 1) Cut end of fuse cord at a slant to expose inner core 2) Light cigarette in normal fashion. Place a paper match so that the had is over exposed exposed end of fuse cord and tie both to the side of the burning cigarette with string. 3) Position the burning cigarette with fuse so that it burns freely. A suggested method is to hang the delay on a twig. Note: Common dry cigarettes burn about 1 inch every 7 or 8 minutes in still air. (Now I am talking about all except American brands, which burn about 1 inch every 4-5 minutes) If the fuse cord is place one inch from the burning end of the cigarette a time delay of 7 or 8 minutes will result. Delay time will vary depending upon type of cigarette, wind, moisture, and other atmospherc conditions (get to know your cigarette!) To obtain accurate delay time, a test run should be made under "use" conditions. DRIED SEED TIMER ---------------- A time delay device for electrical firing circuits can be made using the principle of expansion of dried seeds. Material Required: ----------------- Dried peas, beans, or oter dehydrated seeds Wide-mouth glass jar with non-metal cap Two screws or bolts Thin metal plate Hand drill Screwdriver Procedure: --------- 1) Determine the rate of the rise of the dried seeds selected. This is necessary to determine the delay time of the timer. a) Place a sample of the dried seeds in the jar and cover with water. b) Measure the time it takes for the seeds to rise a given height. Most dried seeds increase 50% in one to two hours. 2) Cut a disc from thin metal plate. Disc should fit loosely inside the jar. NOTE: If metal is painted, rusty, or otherwise coated, it must be scraped or sanded to obtain a clean metal surface 3) Drill two holes in the cap of the jar about 2 inches apart. Diameter of holes should be such that screws or bolts will thread tightly into them. If the jar has a metal cap or no cap, a piece of wood or plastic (NOT METAL) can be used as a cover. 4) Turn the two screws or bolts through the holes in the cap. Bolts should extend about one in. (2 1/2 cm) into the jar. IMPORTANT: Both bolts must extend the same distance below the container cover. 5) Pour dried seeds into the container. The level will depend upon the previously measured rise time and the desired delay. 6) Place the metal disc in the jar on top of the seeds: How to use: ---------- 1) Add just enough water to completely cover the seeds and place the cap on the jar. 2) Attach connecting wires from the firing circuit to the two screws on the cap. Expansion of the seeds will raise the metal disc until it contacts the screws and closes the circuit. FUSE PAPER ---------- Useful for making the fuses for bangers (firecrackers) and other slow-burn fuse applications. You will need: Sodium Chlorate - Go to your local gardenshop/centre and ask for some Sodium Chlorate weedkiller. You're meant to be 18 by law but if you're not it doesn't usually stop them selling you it. Newspaper/Tracing Paper The Sodium Chlorate in the weedkiller is unlikely to be more than about 65% pure - this is not a problem if you're not worried about how quickly it will burn as fuse paper but if you are using the fuses in a lot of wind or are going to through them as part of a firecracker you will have to concentrate the Sodium Chlorate and remove impurities as much as possible beforehand as follows: Make a saturated solution of the weedkiller (ie.dissolve as much of it as you can in very hot water) then filter off any remaining crystals. Then heat the solution very hot in a dish - then when crystals start forming around the rim heat more gently and then leave to cool - after some time u will have crystals with gunge all over them - wash them and filter off any rubbish. This is really simple to make but quite effective...Just take the Sodium Chlorate (pure or weedkiller) and then make a solution of it (put in water). Then soak the paper in the water and leave to dry on a radiator. When the paper is dry it will burn with some loud pops and just as fusepaper so you have made your own fuses. Now to put the fuses to work....(hehe) - Igniter from Book Matches - ----------------------------- This is a hot igniter made from paper book matches for use with molotov cocktail and other incendiaries. Material Required: ----------------- Paper book matches Adhesive or friction tape Procedure: --------- 1) Remove the staple(s) from match book and seperate matches from cover. 2) Fold and tape one row of matches (fold in thirds) 3) Shape the cover into a tube with striking surface on the inside and tape. Make sure the folder cover will fit tightly around the taped match heads. Leave cover open at opposite end for insertion of the matches. 4) Push the taped matches into the tube until the bottom ends are exposed about 3/4 in. (2 cm) 5) Flatten and fold the open end of the tube so that it laps over about 1 in. (2-1/2 cm); tape in place. Use with a Molotov Cocktail: --------------------------- 1) Tape the "match end tab" of the igniter to the neck of the molotov cocktail. 2) Grasp the "cover and tab" and pull sharply or quickly to ignite. General Use: ----------- The book match igniter can be used by itself to ignite flammable liquids, fuse cords, and similar items requiring hot ignition. CAUTION: Store matches and completed igniters in moistureproof containers such as rubber or plastic bags until ready for use. Damp or wet paper book matches will not ignite. HOW TO MAKE A CHEMICAL TIME DELAY FUSE: To get an understanding of how this is going to work, mix up equal parts by volume Potassium chlorate and granulated sugar. Pour a spoonful of the mixture in a small pile and make a depression in the top with the end of a spoon. Using a medicine dropper, place one drop of concentrated sulfuric acid in the depression and step back. It will snap and crackle a few times and then burst into vigorous flames. To make the fuse, cut about 2 inches off a plastic drinking straw. Tamp a small piece of cotton in one end. On top of this put about an inch of the clorate/sugar mixture. Now lightly tamp in about a quarter inch of either glass wool or asbestos fibers. Secure this with the open end up and drop in 3 or 4 drops of sulfuric acid. After a few minutes the acid will soak through the fibers and ignite the mixture. The time delay can be controled by the amount of fiber used and by varying how tightly it is packed. Don't use cotton for this. The acid will react with cotton and become weakened in the process. By punching a hole in the side of the straw, a piece of blackmatch or other fuse can be inserted and used to set off the device of your choice. Potassium chlorate was very popular with the radical underground. It can be used to make a wide variety of explosives and incendiaries, some of them extremely dangerous to handle. The radicals lost several people that way. But, don't worry. I am not going to try to protect you from yourself. I have decided to tell all. I will have more to say about Potassium chlorate, but for now, let's look at a couple of interesting electric fuses. Take a flashlight bulb and place it glass tip down on a file. Grind it down on the file until there is a hole in the end. Solder one wire to the case of the bulb and another to the center conductor at the end. Fill the bulb with black powder or powdered match head. One or two flashlight batteries will heat the filament in the bulb causing the powder to ignite. ANOTHER ELECTRIC FUSE --------------------- Take a medium grade of steel wool and pull a strand out of it. Attach it to the ends of two pieces of copper wire by wrapping it around a few turns and then pinch on a small piece of solder to bind the strand to the wire. You want about 1/2 inch of steel strand between the wires. Number 18 or 20 is a good size wire to use. Cut a 1/2 by 1 inch piece of cardboard of the type used in match covers. Place a small pile of powdered match head in the center and press it flat. place the wires so the steel strand is on top of and in contact with the powder. Sprinkle on more powder to cover the strand. The strand should be surounded with powder and not touching anything else except the wires at its ends. Place a piece of blackmatch in contact with the powder. Now put a piece of masking tape on top of the lot, and fold it under on the two ends. Press it down so it sticks all around the powder. The wires are sticking out on one side and the blackmatch on the other. A single flashlight battery will set this off. An excellent electric fuse can be bought ready made at hobby and toy stores. They are sold for setting off model rockets.