For Fireworks Thump Junkies, Too Loud Is Never Loud Enough

The blast is sudden and deafening, like several sticks of dynamite exploding close by. Although there's no crater, the shock wave pounds my chest. Immediately after the thump, a few men in beards, T-shirts, and old blue jeans laugh and high-five one another.

Shortly thereafter, I hear something else: the sound of dissent. "Geez, they're loud," a man says to me a low voice. "Even though I'm ready for it, it still scares me." He grimaces and sighs. "I don't really like their work."

Pyrotechnics Guild International's annual convention in La Porte, Ind., is a big, bright, loud celebration of DIY American fireworks. But wandering the grounds, it quickly becomes clear that there's a divide in the pyrotechnic culture.

Most members of the pyrotechnical establishment spend their time building elaborate, time-intensive, sky-painting aerial shells. Such people are artists who use the sky as their canvas and fire as their palette. A skilled pyro can craft a shell that spreads colored stars a thousand feet across the sky and make their color change from red to yellow to silver as they go. And the shapes the stars make are incredible, tracing out arcs that resemble palm trees, chrysanthemums, diadems, and even happy faces.

And then there are the thump junkies, who don't care a whit about such artistic niceties. Thump junkies are the pyrotechnics enthusiasts who specialize in building the loudest, most deafening devices, known as salutes, or maroons. What they seek are palpable, eardrum-shattering explosions. Although many attendees at this year's convention don't want to talk about these guys, there's no way anybody can ignore the fact that they're there. "To each his own," one pyro told me anonymously. "But it's not what most of us are really about."

How to Build a Big Bang

Americans love potentially dangerous pyrotechnics, so much so that in 1966 the U.S. Congress tried to protect us from ourselves by passing the Children Protection Act. It was a wise series of laws that in effect outlawed the sale and use of "items so dangerous that cautionary labeling is not adequate." The poster children for such items were the large, loud, and incredibly dangerous firecrackers such as Silver Salutes, Cherry Bombs, and the infamous M-80. These large firecrackers typically pack about 3 to 5 grams of finger-removing flash powder (a mixture of a powdered metal such as aluminum and a powerful oxidizer, typically potassium perchlorate) into a 1-1/2-inch-long cardboard tube. The largest legal consumer firecracker is now limited to 50 milligrams, or 1 percent as much powder as an M-80's.

It worked. If you look at the Consumer Protection Agency's data, fireworks injuries have tapered off like a falling skyrocket, from 38 injuries per thousand pounds of fireworks sold in 1976 to just three injuries per thousand pounds last year. Still, some people can't resist the allure of a big boom, which gave rise to the thumpers.

At PGI, the thumpers hang out at what's known as the ground salute line, an area far away from the main gathering. The salutes themselves are simple devices, cylinders constructed from a paper casing and filled with an energetic mix of potassium perchlorate and aluminum powder. On the line are a number of wooden frames from which the salutes are tied and suspended. By suspending the salutes, two good things happen: The sound effects are amplified, and no flying debris or dirt is kicked up.

There are other ways to fire a salute. For sheer size and volume, it would be hard to outdo the old noisemakers called Gabe Morte. A Gabe Morte, which means "dead head" in Italian, is a huge sack of mixed chemicals suspended from a scaffold at the height of a man's head. When ignited, the dead head explodes, producing a truly enormous noise. It's loud, simple, and primitive. Once a popular way to end a fireworks show, this incredibly loud and dangerous effect is rarely performed anymore, except perhaps by dedicated thumpers on private property.

The Gabe Morte proves how easy it is to build a noisy salute. Basically you mix flash powder and fuel in a bag, attach a fuse, and you're more or less ready to go. The noise comes from the rapidly expanding gas produced, and there isn't a lot to go wrong. (From a chemical-reaction standpoint, that is. From a practical and safety standpoint, there's a lot that can go wrong when you're mixing up a big bag of this extremely sensitive stuff.)

Building a shell, on the other hand, takes experience and craftsmanship. The colors, pattern, and size of a fireworks shell depend on the way the individual elements, called "stars," are made and positioned inside the shell. There's a lot of chemistry, physics, and plain old geometry involved here. Unlike a thumper, it takes years for the pyro craftsman to get really good at shell building.

There are thumpers that have moved beyond "the bigger the boom, the better" attitude. At the upper end of the spectrum are the complex and difficult-to-construct aerial salutes built by some of more ardent loud-sound devotees. These elaborate sound-makers are based on the fireworks-making traditions of pyrotechnics hotspots such as Spain and Malta. Such salutes take days to construct and provide deafening booms for sure. The differences between these and the vanilla salutes are easily discerned; the reports are presented in precisely timed patterns and cadences. Such salutes are lofted high into the air by a lifting charge prior to detonation so the syncopated rhythms of the booms echo for miles.

Midway through the convention, as the sun begins to set, one of the thumpers on the salute line gingerly holds a large Bernz-O-Matic propane torch and approaches a giant salute suspended from a wooden frame. He pushes the torch's trigger, reaches over to light the fuse, then dashes away to take shelter behind a steel shipping container. The fuse burns hot and fast. Seconds later, the salute explodes, and the concussion of an earthshaking pressure wave is felt everywhere.

"Well, actually," one of the shell builders says with a slight smile, "that was pretty cool."

William Gurstelle is PM's pyrotechnics and ballistics editor. The new and expanded edition of his book, Backyard Ballistics, is now on sale at bookstores everywhere.

Source: http://www.popularmechanics.com/outdoors/recreation/for-fireworks-thump-junkies-too-loud-is-never-loud-enough-12701632?src=rss