The work expands to fit the time allotted, so Kate Dale starts her yearly labor in May.

She might talk with other designers about ideas, sifting through themes. Start lining up some materials in the scene shop at The Juilliard School, where she runs the prop department. As June approaches, she begins cobbling things together, building her newest Mermaid Parade float.

Saturday marks Coney Island’s 35th Annual Mermaid Parade, the zany Mardi Gras-esque event that kicks off just south of Neptune and Mermaid Avenues. Launched in the early 1980s by another theater veteran, Dick Zigun, the “art parade” celebrates Coney Island’s history of seaside performance and entertainment through a colorful experience featuring mermaid and merman costumes and vehicles partying near the water. Dale, 54, has been a fixture at the event for more than two decades.

She came to New York City from Michigan for the theater. One year she opted not to take a summer thespian job. Her friend invited her to check out the parade. “This is for me,” she said immediately — the people dressed flamboyantly and sometimes sparsely. The ingenious floats, the lighthearted crowd. It was a mix of “kitsch and craft and glamor,” she says, and “art for art’s sake.” She was hooked.

Working in prop design necessitates both skill at fixing things and a curious mind — being good with your hands plus “knowing something about the Russian Revolution” and period decor, says Dale.

Some of those talents surface in her float-making, as with the silver coin she fashioned for the 25th anniversary parade, complete with Roman-style ornamentation.

This year’s float is a coral tiara that will, as usual, include a seat for Dale in her mermaid costume.

The coral is made from papier mache; the seat ringed with cardboard, wire and glue in seaweed-like forms. The contraption is made stable by the recycled ribbing of a boat from a dance production. “We need more support,” Dale acknowledged during a sneak peak of the float on Friday.

Some of the materials are scavenged or borrowed from Juilliard’s theater — she’s using a flange from the scene shop to strengthen the base. Some of the float is reincarnated, such as the steel handle welded by a friend of hers in 2002, so her handful of mer-attendants can push her along.

Motorized vehicles are allowed in the parade and once, Dale retrofitted an old VW Super Beetle into a lobster. But cars are banned from the section that goes along the Coney Island boardwalk, which Dale says is the best part. So she goes with a push cart, riding high.

The prop master has unsurprisingly found success with the Mermaid Parade judges, winning best mermaid and best float multiple times (she was second place mermaid last year, to a longtime participant and burlesque performer).

Still, from time to time the float experiences “catastrophic failure,” as when a few years ago she hung a cooler from the push bar. Between the weight of the ice and the beer, the float came apart just before the start of the rainy-day parade. But mermaid magic and Dale’s handiness made it work.

“Thank God for some three-inch drywall screws,” she says. She and her team also lightened the cooler’s load.

In recent years, there tend to be two cyclical narratives about the Mermaid Parade: 1) that it’s getting less weird, and 2) that it’s financially endangered.

Dale vehemently disagrees with the first assertion. Begun in part as a way to honor the area’s traditions and history, Coney Island’s entertainment district has to some extent experienced the “renaissance” some early parade goers might have hoped for. But the parade is still plenty strange, and fun, and sometimes barely-clothed. (Dale says she has a relatively “modest aesthetic” for her own fins, though her attendants’ costumes tend to be more “brief.”)

The parade did hit financial troubles this year, requiring some last minute donations. But the show will go on, for both participants and the thousands of viewers who come to semi-officially launch the Brooklyn summer.

For Dale, the parade is a break from the usual stresses of the theater — she is part of some 20 shows a year, working 80-hour weeks when things get busy. The parade is an opportunity to create something that’s her own vision, as opposed to ably supporting the visions of others as she tends to do in her regular work.

“At this point it’s a habit,” she says with some fatigue of the yearly event. But then, sometimes she considers moving from New York and realizes she must happily decide against it: “I have to do the parade.”