Flash Powder Output Testing: Weak Confinement

K. L. & B. J. Kosanke

ABSTRACT: A variety of flash powders were tested under weak confinement to determine the sound pressure levels and tonal characteristics produced. In these tests it was found that: the sound output from mixtures prepared with potassium perchlorate from four manufacturers are essentially equivalent; there are significant differences in the level of sound output as a result of using six different common aluminum powders; the addition of either of two common flow or bulking agents have essentially no effect on the sound produced; the substitution of potassium chlorate for potassium perchlorate in a common flash powder has essentially no effect on the sound produced; and the addition of antimony sulfide or sulfur reduces the duration of positive phase without increasing the level of the sound produced. In short, it was found that nothing surpassed the level of sound produced by a 70:30 mixture of reasonably high-quality potassium perchlorate and a high quality flake aluminum powder. This is significant because the use of potassium chlorate, antimony sulfide, and sulfur, can seriously increase the sensitiveness of flash powders to accidental ignition.

Keywords: flash powder, sound pressure level, blast pressure, weak confinement, positive phase

Ref: Selected Pyrotechnic Publication of K.L. and B.J Kosanke, Part 4, (1995-1997), pp 83-93
(K4_83)

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