SLIPPERY ROCK, Pennsylvania (AP) — Love fireworks? About 2,000 members of the Pyrotechnics Guild International are gathering this week in the U.S. to discuss and build fabulously complex comets, rockets and exploding shells for fun.

One tent promises you'll "learn to make almost perfect Gasoline Fireballs." Another offers "Pyrobilia," or collectible fireworks.

The event includes serious security to monitor the gunpowder and assorted mixtures that can sparkle, burn or explode.

The PGI has about 2,600 members from 30 different countries, including China, where gunpowder was invented and firecrackers remain an important part of the culture.

Aside from the camaraderie, the attraction is simple, said Aaron Enzer, a past president of the group.

"They can build things here, and go out and shoot them right away," he said.

Members of the public can't go to areas where the explosives are sold, or buy any of the fireworks. Access is tightly controlled by guild members.

But there are fireworks displays for the public most evenings, along with music and food.

The special displays come down to one thing, said Tom Rebenklau, a two-time PGI Competition Grand Master.

"There is no magic to this stuff," said Rebenklau. "The secret is the last four letters— fire W-O-R-K."