Friction Primer Compositions

Davis (1943), 400-53 (Primary expls, detonators and primers) 453-54 (Friction primers) 454-58 (Percussion primers) 9a) D. Hart, "Compilation of Data on the Composition of Foreign Igniters and Tracers",... 

Friction Compositions for Friction Detonators Friction Firing Devices and Friction Igniters or Primers. These are powders which are easily ignited by friction. Some of the simplest mixtures are K chlorate with sugar or with antimony sulfide. Davis (Ref 1, p 453) gives table listing three compns which have been widely used in friction primers for artillety, separate-loaded ammunition... 

Compositions used in friction primers are listed under Friction Compositions (Compare with Friction Detonators and Friction Firing Devices)... 

The following tabic shows three compositions which have been widely used in friction primers for artillery. All the materials... 

Striker Composition. See under Friction Primers in Vol 8, P386-L R... 

Port-fire. A paper tube filled with a composition of niter, snlphur, and mealed gunpowder fomerly used to fire gnn.s. Now superseded by the friction-primer and gun-lock. 

The most common friction primers arc those that translate push or pull energy into fictional energy. This is accomplished by movement of a rod or wire through a fiiction-sensitive compound. Tb accent the production of friction, the rod/wire may be roughened or granular material may be added to the explosive compound. Listed below are the percentage of composition and parts composition for three typical friction primer compounds. 

Tetryl (C7H5N508) is a pale yellow crystalline solid. It is moderately sensitive to initiation by friction and percussion and is used in the form of pressed pellets as primers for explosive compositions that are less sensitive to initiation. It is slightly more sensitive than picric acid and considerably more sensitive than TNT. In the early 1900s, tetryl was used as base charges for blasting caps but now has been replaced by PETN and RDX. During World War II, tetryl was used as a component of explosive mixtures. 

Both 2,4-dinitrosoresorcinol (23) and 2,4-dinitroresorcinol (24) are important in the explosives industry. The lead salt of 2,4-dinitrosoresorcinol has a low ignition temperature and finds use in priming compositions and in electrical igniters. The lead salt of 2,4-dinitroresorcinol is a weak initiator but is found to exhibit high sensitivity to friction and stab action without being highly sensitive to impact, and as such, this compound has found use in primers. 

Civil explosives are also known as commercial or blasting explosives and are typically used for mining, quarrying, construction and tunnel building. They are chemical compositions, which detonate when initiated by high explosive primers or boosters or directly by detonators. They are relatively insensitive to shock, friction or impact... 

Abrasive. Any grinding or polishing material, such as emery, ground glass, carborundum, infusorial earth, pumice etc. Some of these materials are used in priming compositions in order to increase the sensitivity of other components (such as MF, KCIO, etc) to friction or impact. Crystalline SbaS3 used in priming compns functions not only as a fuel but also as an abrasive(See under Primers)... 

Many of the compositions suitable for use in Percussion Primers (such as listed in Ref 3, pp D792-R to D805-R) may be ignited not only by percussion but also by friction. 

Frlc tloihtabe. (Ordnance.) A tube containing a composition which is Inflamed by friction, and which is placed in the vent of a gun to ignite the charge when the lanyard is pulled. See FRICnON-PRIMER. 

---