Coming Saturday: 21 minutes of dazzling sky
The three rusty, groaning barges anchored yesterday in the middle of the Charles River have all the glitz and excitement of a construction site: power tools, mounds of sand, rough-cut wooden framing, a dozen workers in hard hats, and a portable toilet.
The difference: 25,000 pounds of fireworks, 5 miles of yellow wire, and one green button marked “GO.’’
“It’s a huge undertaking - huge to set up and big to tear down, ’’ said Art Rozzi, a soft-spoken purveyor of handmade Italian fireworks whose great-grandfather learned the trade in a town outside Naples.
After five days of hammering and sawing and unloading three tractor-trailers filled with explosives and electronics, the crew yesterday began the finesse work. That meant stuffing more than 5,000 mortar tubes with the charges, stars, and bursts that will illuminate the sky for 21 minutes Saturday night.
The work is tedious, using yellow wire to lower hand-size sacks of pyrotechnics into tube after tube. The mortars vary in size, from the 3- to 4-inch front line that throws colors at an angle some 400 feet in the air to the 12-inch behemoths buried in barrels of sand that blast fireworks 1,200 feet above the river.
“I’d like the fog to go away,’’ said production coordinator Bernie Durgin, who glanced up at the low, gray sky. “The big shells will disappear up in that fog.’’
No amount of planning - or explosives - can influence the weather. The crew enjoyed the cool temperatures yesterday that came with the fog and rain. The forecast for Saturday night left a slim possibility for clear skies, which would be a perfect canvas for Rozzi’s Famous Fireworks Inc. of Loveland, Ohio.
“This is really exciting for me to do this,’’ Rozzi said as mist collected on the Red Sox hat he had bought for his first fireworks spectacular on the Esplanade.
“Boston is a premier show,’’ he said. “In my eyes, it’s one of the shows mentioned when they mention the Fourth of July.’’
Andrew Ryan can be reached at aryan@globe.com. 
