1306308 Flash-bulbs GTE SYLVANIA Inc 22 Oct 1971 [22 Oct 1970] 49278/71 Heading G2L A method of applying fulminating material to the primer of a percussively-ignitable flash-bulb comprises the steps of applying a phosphoruscontaining coating to the primer, drying the coating and causing a chlorate salt to permeate through the coating from a chlorate salt solution. The coating may contain red phosphorus or phosphorus sesquisulphide and the solution is preferably an aqueous solution of sodium chlorate, although other chlorates having a solubility of at least 15% by weight in water, such as those of calcium, lithium, magnesium, aluminium and zinc, may be used.
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