Pyrotechnics first fires

Igniter composition used with pyrotechnic devices that is loaded in direct contact with main pyrotechnic charge. Pyrotechnic first fire composition compounded to produce high temperature. Composition must be readily ignitible, and be capable of igniting the underlying pyrotechnic charge. 

Accdg to Ellern (Ref 57, p 189), the terms "first fire" and "starter" refer in pyrotechnics not to the "prime ignition" but to the "intermediate ignition" source which is located between "primary initiation "and the "main pyrotechnic item , such as flares, signals, etc. 

The oldest and still widely used in pyrotechnics and fireworks "first fire" and "starter" mixture is BkPdr. It belongs to mixts without metallic ingredients. Metallic mixts contain combustible powdered metals, such as Mg, Al, Zr etc. Metalloids B and Si are considered metallic fuels because of their similarity in pyrochemical behavior to metals. Although BkPdrs are described in Vol 2 of Encycl, pp Bl65ff, we are giving here as Table E compns of three formulations used in pyrotechnics, as described by Ellern (Ref 57, p 375)... 

When used with highly compacted main pyrotechnic items, such as flare candles the "first fire" is either pressed (in dry form), or painted (in paste or slurry form) on top of item. For initiation of solid proplnts, a "first fire " mixt can be ignited if confined in a tube or capsule so that the hot gases will be spread over a larger surface area (Ref 57, pp 189 91) Table F lists various formulations for "starter mixtures" Table G for "ignition mixtures" and Table H for "first fire mixtures". -These formulations are given in Ref 57, pp 377-83. Some mixtures are taken from Ref 44a,... 

Anon, "Engineering Design Handbook. Military Pyrotechnics Series. Part One. Theory and Application , US Army Materiel Command Pamphlet AMCP 706-185 (1967), pp 5-29 to 5-37 (Pyrotechnic delays) 5-37 to 5-40 (Ignition compns for gasless delay elements) 5-45 (Initiators, first fires, and star ter s) 5-45 to 5-46 (Pr ime ignition) ... 

Lusardi (Ref 24) describes in Section 300 analytical procedures for the following compositions used in pyrotechnics igniter, first fire, flash, matchhead, delay and relay Method No 320. Igniter Composition, Aircraft Signal Type - Red lead 33-1/3, CuO 33-1/3 Si 33-1/3 [US Army Spec No 50-55-9 (1946)1... 

First-fire. In pyrotechnic devices, an easily ignitabic compn between the fuse (or other igniter) and the main charge. The main charge is not easily ignited by die fuse alone. The same as Igniter Composition (See in Article on Pyrotechnics)... 

First Fire, Ignition end Starter Mixtures Used in Pyrotechnics such as defined in Dr Ellem s book are listed in Vol 4, pp D763 to D767 and in Tables F, G, H and I... 

First Fires, Igniters and Starters in Pyrotechnics. Their definicions are given by Dr H. Ellern in "Military and Civilian Pyrotechnics , ChemPubgCo, NY (1968), p 189. See Vol 4 of EnCycl, p D760-L... 

The pyrotechnic formulations such as 50% CaSi2 and 50% Fe304 which are relatively cool and gasless, have been extensively used in the past for the manufacture of self-heating food cans. The cool and gasless pyrotechnic formulation is held in a central tube with a CaSi2/Pb304/clay formulation as the first fire formulation. 

Heat-producing pyrotechnic compositions are used in a variety of applications, for example, as first fires in pyrotechnic devices to ignite other materials, as primers, as heat generators in pyrotechnic heaters, as propellants in gas generators and rocket motors, and as incendiary devices. 

Pyrotechnic compositions which are used in primers or first fires are very sensitive to initiation, whereas compositions which are used in heat-generating devices are less sensitive. The sensitivity of the compositions can be controlled by reducing the amount of oxidizer and choosing a less sensitive oxidizer. 

First fire pyrotechnic compositions are used to ignite other compositions which are less sensitive to initiation. An example of a first fire composition used in fireworks is blackpowder. The blackpowder is moistened with water containing dextrin and poured on to the top of the firework composition as shown in Figure 8.3. 

Pyrotechnic mixtures which are used for ignition in blasting caps or detonators or which are used as first fires in propellant charges, are very easy to initiate. Here the initiator generates a flame if it is hit with a metal (percussion primer) or if it is initiated electrically using resistance heating (bridge wire). The first fire then initi-... 

For pyrotechnic use it is combined with ferro silicon under the name of "Red Thermitwhich is used as a first fire composition for compositions which are difficult to ignite. Or it is also used to display orange fire dust in combination with other compositions. The red thermit is said to generate no gas in the burning reaction, but truly a small quantity of gas is generated. 

With the exception of the hand grenade, type AN-M8, which contains 19 oz of HC mixture (2 min B.T.) and is thrown, HC-smoke munitions belong to the largest of the strictly pyrotechnic munitions. The Ml Smoke Pot (ffC) contains lO lb, the M5 Smoke Pot HC) 301b of composition in addition, they can be stacked for multiplication of the 5—20 min of smoke emission. First fires for the HC-smokes will be discussed in Chapter 23. 

The specific functions that fall into this category are first fires and igniters for pyrotechnic mixtures and solid propellants fire transfer... 

The theory of initiation has mainly been expounded in the field of solid-propellant ignition. A recent effort for pyrotechnics has been published by Johnson.The calculations are difficult since they involve calories transferred to the surface of the initiated column at certain temperatures and over a time interval heat absorption and flow in the main item, heat developed in the main item from the incipient final reaction, and, of course, heat losses. Johnson advocates on the basis of theoretical considerations a small area on which lire transfer is concentrated low thermal conductivity, density, and specific heat of the first fire and use of high-energy, flare-type first fire mixtures in such a way that radiant heat transfer is optimal. 

First fires without metallic fuel are nowadays mainly found in fireworks items. The most important one of this class is black powder. It is fairly safe to handle, often serves as a combined ejection and ignition material, and is itself easily ignited over a wide range of temperatures and at diminished atmospheric pressure down to about 0.1 atm. Its property of fouling metal parts because of the corrosiveness of its reaction products need rarely be considered since pyrotechnic devices are one-shot items and if ejected from reusable dispensers their own expendable case is the actual gun barrel. Black powdo has been discussed in some detail in Chapter 20. 

First fire An easily ignited composition that is pressed, coated, or otherwise placed in limited quantity on top of the main pyrotechnic mixture. The first fire is reliably ignited by a fuse or electric match, and the flame and hot residue that is produced then ignites the main charge. Black powder. 

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