Freezing the stages of the world - a hi-tech wonder

When ice dancer John Curry glides out on the stage, he's spinning on one of the biggest and most ambitious ice cubes in history - weighing 20,000 pounds. Curry takes his ice with him, thanks to a 20-year-old Wunderkind who is steeped in the laws of thermodynamics and refrigeration technology. Curry's personalized ice is the work of Kevin Kossi, a New York University student who is carrying on a family icemaking tradition. Both of Mr. Kossi's parents had been stars of the Holiday on Ice show and turned later to icemaking as a family business. His father is icing over a Broadway stage for a forthcoming musical, ''Electric Ice.''

When the iceman cometh to Kennedy Center - or any of the show's stops from Boston to Tel Aviv - he brings two tractor-trailers with him to create an instant ice rink. And it's not just any ice, it's star ice.

''We have to produce perfect ice for John,'' says Mr. Kossi, ''especially on the openings.'' Each skater likes a different kind of ice to perform on, Kossi points out. ''Hockey players like the ice hard, figure skaters like it soft for jumps and spins. John likes it at 25 degrees F., a certain softness, a certain hardness. He likes it in between, not too soft, not too hard.'' Opening night at the Met for John Curry's ice dancing was delayed by a day because the ice was a bit too slushy, the result of a new computer that needed readjusting, Kossi says.

Yes, computerized ice. But there has to be a human ice expert to tell the computer what to do. And that's Kevin Kossi, who reels off the recipe for making perfect ice-dancing ice: The ingredients include 14,000 gallons of water; 2 layers of plastic 40 feet wide and 100 feet long, the thickness of a photograph; one layer of Styrofoam insulation 11/2 inches deep; wooden boards to create the perimeter of a rink 41/2 inches high; and 24 miles of plastic tubing to be filled with ethylene glycol, the green antifreeze that circulates through the tubing and absorbs the heat from what's going to be the ice.

The glycol is polar-bear cold: 10 degrees above zero. The ingredients, from plastic sheeting to tubing, are layered like a club sandwich. When the tubing reaches 10 degrees to match the glycol in it, Kossi begins spraying a light mist of water over them until a level surface is achieved. Then it's allowed to dry for half an hour.

''We do that continuously for 30 hours,'' says Kossi, so that when we open up (in the performance) there's 11/2 inches of ice surface.'' Laying the rink takes eight hours, so the total operation requires 38 hours nonstop on the job for Kossi. By opening night they have used 7,000 gallons of water on stage, weighing 20,000 pounds. By closing night the ice is 31/2 inches thick, contains 14,000 gallons of water, and weighs 40,000 pounds.

''I have to monitor the ice, although it is computer ice, to adjust and readjust it to different levels,'' Kossi says. ''When the lights hit it, there's a big load on it, and if we don't anticipate that, the ice gets moist and soft.'' Even a quarter of an inch of ice can make a crucial difference, he notes. If it were only 11/4 inches thick on opening night, rather than 11/2 inches, it would be dangerous, because a skater landing after a jump would go through to the tubing.

The only real problem Kevin Kossi worries about is a blackout, which would knock out both the generator and all the icemaking equipment. ''It takes enough electricity for a 12-story building,'' says Kossi, who requires that each hall have a standby generator. (That indeed happened at the company's Boston opening last summer, when a power outage threatened to turn the Wang Center for the Performing Arts into a sea of water. A last-minute heroic effort by the promoters and friends produced a rented emergency generator that refroze the ice and saved the show.)

At Kennedy Center, Opera House manager Mary Jo Ford had to clear a swath 60 x 80 feet, wider than the proscenium, to squeeze in the rink. It stretched across the black masonite floor off into the wings and the loading doors. In fact, the temperature on stage was cold enough for some stage hands to wear ear muffs.