Laurie Adkins sang as she walked room to room at the Metro Arts Center, using a pair of tongs to hold a metal canister heated to 1,000 degrees.

"It's like a dance," she said, announcing the hot canister's presence as she wove through students in her Lost Wax Casting class.

The class has grown in the last couple of years, increasing from four or five students to as many as 12 in recent sessions, with some traveling from as far as Cincinnati, Adkins said.

Wax casting is a common technique used in commercial jewelry-making but is rarely taught outside of art school. It allows jewelers to work with three-dimensional pieces, instead of cutting separate pieces and soldering them together. But the necessary equipment is expensive, and so is studio time at other locations, participant Joanna Jorgensen said.

The only other class she found in Louisville cost about $1,600 for six weeks, she added. The center's course is $70 for eight weeks.

On Thursday, the class members shifted between two rooms. Some worked on jewelry designs at tables in the center room, while others cast their pieces in an adjacent one.

Wax casting is at least a three-class process. It starts with jewelers molding a design — for a ring, bracelet, pendant or other item — out of wax. The design is then attached to wax sprues, or "little highways" that will carry metal to the design, participant Peggy Kinnetz said.

The wax piece is placed in a metal canister, which is filled in with plaster. Then the canister is put in a kiln and heated to 1,000 degrees over the course of seven to eight hours. While in the kiln, the wax melts away, turning the plaster into a mold that will be filled with liquid metal.

Then comes the fun part. The canister is placed in a centrifuge, a piece of equipment that spins around so fast it rattles the table it sits on. As it spins, melted metal shoots into the canister and fills the mold.

The final step takes a matter of minutes, but it's the best time for something to go wrong. For example, metal might not have filled part of the mold, the wax could have been too weak or the plaster too porous, Jorgensen said.

"Don't get married to it until it comes out," Adkins repeatedly warns.

Jorgensen, a professional jeweler, has learned to prevent mistakes by casting each design three or four at a time. For a customer ordering an engagement ring, she made four of the same lotus flower with a setting at the top and let the customer choose one.

The ring would have looked different if Jorgensen had made it with traditional metal-smithing techniques, she said. It wouldn't have been one solid piece.

"It's a hard time going from fabricating to three-dimensional," she said. "It takes a minute to figure out what you can do in the wax and why you would use this method to make the jewelry as opposed to a different method."

Once they're finished, Adkins said the metal pieces will last forever.

"When you look at ancient art, most of it is metal or something," Adkins said. "A lot of people are making heirlooms in here."

Reporter Bailey Loosemore can be reached at (502) 582-4646. Follow her on Twitter at @bloosemore.

What: A jewelrymaking technique that involves making a mold with wax and shooting liquid metal into it.

Where: Metro Arts Center, 8360 Dixie Highway

When: A session is currently in progress. Go to www.louisvilleky.gov/MetroParks/recreation/metroarts.htm or call (502) 937-2055 for more information.