(AP) One tent promises you'll "Have fun and learn to make almost perfect Gasoline Fireballs." Another display provides tips on "Black-Powder-Coated Rice Hulls for Lift and Burst, An Easy Way, Using an Optimized Ball-Mill and Star-Roller." You can also check out "Pyrobilia," or collectible fireworks.
Those topics and other explosive endeavors are on the agenda for about 2,000 members of the Pyrotechnics Guild International and their families who are gathering this week in western Pennsylvania for their annual meeting at a scene that's part backyard laboratory, part country cookout.
It's a place for die-hard pyrotechnics lovers who build fabulously complex handmade comets, rockets and exploding shells for fun and from scratch. It's all overlaid by serious security, in order to monitor all the gunpowder and assorted mixtures that can sparkle, burn or explode in just about any way imaginable.
These aren't bottle rockets.
"It could literally take a couple of weeks" to build a 24-inch exploding shell, for instance, said Aaron Enzer, a resident of Manchester, Mich., and a past president of PGI. Such a project can contain as much as 185 pounds of gunpowder, since the main shell can be filled with hundreds of tiny custom pellets of gunpowder, each hand-mixed to produce different patterns and colors upon detonation.
It's also not cheap.
"Just purely the raw materials on a 24-inch shell, you're looking at $800 to $1,000 in costs," said Enzer, 39, as he watched people build rockets in a tent open only to guild members.
The PGI was founded or resurrected, rather in 1969 and has about 2,600 members from 30 different countries. Its logo is a 1600s woodcut of a "Green Man." In that era, the story goes, members of the secretive fireworks guild would cover their bodies with green leaves to keep the crude explosives from burning them.
The traditional salutation among those early fireworks makers was "stay green," according to guild members, who still use similar phrases.
At the event, usually held in the West or Midwest but happening this year at a private campground about 40 miles north of Pittsburgh, there's a pyrotechnics art show, events for "junior pyros" and even a wedding for a couple who met and were engaged at a past PGI conference.
For some, it's a way of life.
"I've been coming to the PGI since I was 3 for 22 years," said Brent Anderson, a carpenter from Minneapolis who builds sets for plays.
Aside from the camaraderie, Enzer said, the attraction is simple.
"They can build things here, and go out and shoot them right away," he said.
Local tourism officials got special permits from the township for the event, and members of the general public can't go to areas where the explosives are sold, or buy any of the fireworks. Access is tightly controlled by members of the guild.
But there are fireworks displays for the public most evenings, along with music and festival food.
The special displays come down to one thing, said Tom Rebenklau, a two-time PGI Competition Grand Master and member of the New Hampshire Pyrotechnics Association.
"There is no magic to this stuff," said Rebenklau, a tool maker by trade. "The secret is the last four letters fire W-O-R-K.
"The time is ungodly," he said, noting that mass production can't provide the type of precise displays he can create by crafting fireworks down to a few thousandths of an inch in detail. "You could not do any of this stuff in production. What, are you kidding me?"