SACO — It looks like wood, but it’s impervious to water, salt, oil, chemicals, insects and vandalism. Oh, and it comes in four colors — light gray, weathered wood, white and cedar.

It’s plastic “wood,” made from ground-up milk jugs that have been recycled into a kind of plastic lumber. And its recent incarnation — as the classic Adirondack chair — caused a stir with hundreds of visitors at the New England Flower Show this spring who were drawn to a sign that read: SIT ON ME! I’M MADE FROM 240 MILK JUGS!

“The recycling part really caught people’s attention,” says David Sparks, who a year ago bought Conversion Products Inc., which manufactures the chair. “But they were also impressed by its durability and looks.”

Plastic lumber won’t rot, splinter or crack. It doesn’t fade. It’s odorless. The only downside, says Sparks, is that it bends. So his company bolsters the Adirondack chairs with braces and other furniture with metal supports.

When Sparks bought the Maine-based business, it sold primarily benches, picnic tables and trash receptacles to cities and towns for use in parks, golf courses and zoos. To broaden his base, he decided to venture into residential products. Thus was born the plastic-wood Adirondack chair — and flower boxes, planters, garden benches and a footstool to go with it.

He says visitors to the Flower Show, where he test-marketed the residential products, offered up a host of ideas. “We were using galvanized screws and people told us we should switch to stainless steel. We did,” he says. “They suggested we put legs on the planters. And we did that too. And they thought the garden bench was too wobbly so we made the seat shorter, put braces underneath and made the frame more rigid.

Conversion Products’ wares are assembled in the back of a warehouse in a bland industrial park south of Portland and then shipped directly to the consumer. The “we” in Sparks’ conversation refers to his next-door neighbor, Creative Work Systems, a company that trains and supervises disabled adults.

“I hire their employees to fill orders as needed,” says Sparks, who grew up in Stow, Mass. Sparks graduated from Tufts in 1973 with a degree in public administration, received a master’s from the Kennedy School in 1977 and worked in politics for 25 years before becoming the only investor and full-time employee of Conversion Products. “It’s worked out very well because I can hire high-quality workers on a temporary basis. And because they are supervised, it allows me the time to concentrate on sales and marketing” from a small office in Portland.

And just how did Sparks get from politics to manufacturing? He began his political career by running for Massachusetts representative (Hudson, Stow, Marlborough) at age 23. He lost by 188 votes. He then went to work for the Boston Finance Committee, for Sheriff John Buckley, managed Gerald Ford’s presidential primary campaign in Massachusetts in 1976, and was national field director for the Bush campaign in 1980. By 1989 he was vice president of the Eddie Mahe Co. in Washington, specializing in corporate public affairs consulting.

“My career had evolved into being a political consultant and I think a lot of consultants have wistful thoughts of doing something other than giving advice,” says Sparks, who moved to Maine in 1992 with his wife and opened Sparks & Co., a public affairs consulting firm. “I think we all want more hands-on work.”

It was his brother, a lawyer, who told Sparks about a client of his, David McAllister of Rochester, N.H., who had an 8-year-old part-time business making park benches and picnic tables from recycled milk jugs. It was a custom-order shop that McAllister ran out of his garage.

Sparks called McAllister and the two talked business for several months. Although the 55-year-old McAllister thought his venture had potential, says Sparks, he didn’t feel he had the time or energy to make it grow. So Sparks pulled together his life savings and bought Conversion last July.

It was what he was looking for — a product that was exportable outside Maine, not dependent on high-tech skills and one for which he could use his communication and marketing experience.

Sparks is quick to note that he has not had a long love affair with recycling — after all “I’m a Republican, but I’m now very much interested in recycling, as you can imagine,” he says with an impish smile.

What pushed him into a home and garden line (one of the other prime uses of plastic lumber is boardwalks for theme parks like Disney World and Sea World) was that it takes months and sometimes years for municipalities to place an order. So he is hoping to fill this gap by marketing his home furniture through upscale garden shops.

“We charge $395 for a park bench. Benches using long-lasting woods such as mahogany or purple heart would be in this range,” says Sparks, who packs his Chrysler van with his furniture when on a selling trip. The Adirondack chair is $225, planters $95 and $150, and flower boxes, $45, $55 and $65. The furniture is sold directly from the factory but will be in retail outlets by spring.

Meanwhile, Sparks is always looking ahead. Next year he wants to make trellises, a suggestion that came from a Flower Show visitor. “She was talking about how you can’t paint a trellis once the vines start to cover it and that plastic wood would be perfect,” says Sparks, adding that you not only don’t have to paint plastic wood, you can’t paint it.

(Conversion Products Inc. can be reached by calling (800) 333-0367.)