Zoom July 2012
Published: Friday, June 22, 2012
Words: Michael Isenbek Photo: Stephen Lang
A fireworks display is the grand punctuation mark on many a celebration, and there are numerous levels of intensity as designated by the US government. “Class 1.1G” fireworks are at the high end of the range, warranting an official “Mass Explosion Possible” warning. At the low end is “Class 1.4G,” containing such backyard fireworks fodder as firecrackers, bottle rockets and sparklers. And while 99.9 percent of all fireworks are of the “light fuse, get away” variety, sparklers are meant to be held. Required elements for a typical sparkler are a metallic fuel to produce sparks (aluminum and/or magnesium or titanium for white, iron for orange and an iron/titanium mix for yellow-gold), a nitrate oxidizer to assist combustion and a binder such as dextrin or nitrocellulose. Optional elements are sulfur or charcoal to control burning speed and a wide range of metallic pyrotechnic colorants to widen the color palette of the sparks. All elements are mixed to produce a “composition batter,” then a thin metal rod is inserted into the batter, removed and left to dry.