Selma Hurwitz has kept the details of her artwork to herself for 17 years, and she doesn't plan to reveal them any time soon.

As the originator of "had-ba-kah" (which means gluing in Hebrew) and so far its only known practitioner, the Potomac artist has been reluctant to demonstrate her method of gluing brightly colored metallic threads on the black-flocked surface of museum board.

But Hurwitz has shared the finished works of art with the world. She was the first American artist to have her work hung in Israel's Knesset (parliament) building in Jerusalem. The picture, entitled "Thy Builders Have Perfected Thy Beauty," depicts Israelis working at tasks that contribute to the building of their country. It hangs in the prime minister's office. Another of her works, "How Alone She Sat," is on display in the exhibition hall of Yad Vashem, the country's memorial to the Holocaust victims.

After being exhibited in Montreal at the 1976 Olympics, her "Memorial to the Munich 11" is now permanently displayed at the Joseph P. Kennedy Foundation for Special Olympics in the District. Eight of her other works line one of the walls in the main lobby of the B'nai Israel Congregation in Rockville.

But of the estimated 300 works Hurwitz has completed, the one that she says represents the most growth in her art form was dedicated at Bethesda Presbyterian Church just over a year ago--her first work to hang in a Christian church.

She called the circular work, which is 40 inches in diameter, "Creation." Four years ago the fine arts committee of the church had purchased some of her silk-screen prints, and six months later it commissioned her to do an original.

Hurwitz says she spends a great deal of time researching her works. "I spent six months on the theme of 'Creation' and 10 months putting down the threads for it. I really and truly must understand the subject."

Hundreds of the books she uses in her research tower over her while she works at the drafting table in her home. She won't divulge the half dozen steps of her technique or the specific tools used in had-ba-kah. But she will say that she first creates a detailed sketch of her theme to use as a pattern. She glues the threads onto the museum board one at a time, and once a thread is glued, it cannot be changed.

Hurwitz injects feeling into her work by the way she fashions the threads. The iridescence of the threads and varied thread direction enhance the three-dimensional illusions of the works.

A self-taught artist, Hurwitz says she is forever changing aspects of her technique. By experimenting with new textures and colors, she discovered a method of stripping the outer covering of the metal threads to expose a white cotton tuft underneath. This gives added texture to objects such as flower blossoms, wool or the hair of an older person.

She also experiments constantly with the thread in trying to find a consistent method of creating shadows. She can weave her threads to portray minute, intricate details: tiny shells, tears in the material of a coat, the stain of a goat's blood or a horse's muscular pattern.

Biblical passages, Hebrew letters and even her name are worked into some of her pieces. The faces of living persons also have influenced her. In "Creation," the top part of the central figure's face was inspired by her father, the bottom part by her husband.

Since the cost of an original work of had-ba-kah can range from $200 to $25,000--the estimated value of "Creation"--buyers often settle for a silk-screen print of it. A local printer, Lou Stovall of The Workshop in the District, has been silk-screening Hurwitz's originals since 1973 for interested customers.

"If the price of my artwork was based on an hourly rate, I would be grossly underpaid," she says. Although she says she finds it difficult "to part with any of my pieces," she has sold more than 90 percent of them.

Hurwitz is deep into her next project. Already she has sketched for 220 hours on a large piece depicting the faces of Soviet Jewry, a project inspired in part by the fact that her grandfather died in a Russian pogrom. She has worked to make each face show fear, anger and pain, and has included images of herself, her husband and her three children.