Fairfax couple Art and Nancy Smith, who laughingly dub themselves "professional volunteers," first became involved in playground construction after investigating the costs of school playground equipment.

"We found out that one piece of manufactured equipment could cost $5,000, and for between $11,000 and $18,000 we could build an entire playground which would cost $75,000 if commercially built."

The cost savings, together with architect Bob Leathers' success in organizing volunteers and garnering donations, convinced them to coordinate construction of a playground at Lord of Life Preschool, Fairfax County. (They have since helped complete another at Little Run Elementary School, Fairfax.)

"We just believed it could be done, because we saw the end result at other schools," says Art Smith, 37, "and because Bob was so convinced it would work."

Leathers' Pied-Piper charisma comes into play at the first of two sessions he has with the core committee. "At that point," says Smith, "he has to charge everyone up enough to carry them through the entire nine months of planning."

Part of Leathers' formula is to break the project into parts, each of which is chaired by one person.

The volunteers are given a complete list of materials which may include such items as 40 2-by-6-by-16 boards (southern pine), 1,000 linear feet of telephone poles, 120 tons of stones (rounded, 1/4-inch), 20 wooden spools and assorted hardware. Nothing is purchased, however, until two months before construction in hopes that most of the materials will be donated.

"It's like a big scavenger hunt to see how much of the materials list you can get at no or reduced costs," says Smith. "Part of the trick is to find the people in your community, such as the contractors, who have contacts you can use."

Leathers provides a how-to sheet on fund-raising. Income at Little Run totaled $3,200 from a jumpthon, $1,400 from a flower bulb sale, $5,300 from parent donations and $1,500 from auction of business-donated articles. About $2,500 went to Leathers and his two assistants, and the remainder for materials.

"Leathers tries to help you construct a playground you can afford," says Nancy Smith, 41. "He cut costs in our case by building four playgrounds in Fairfax County over the last two weekends of April, so we could all share his transportation costs. He also stays in committee members' homes so there are no hotel bills."

However smoothly the step-by-step planning process goes, the moment of reckoning comes on the first day of construction.

"Up until that moment everything is in your control," says Art Smith, "but there is a real element of risk in whether the volunteers will actually step forward."

About half of Little Run's parent population did work a shift, and the turnout is due in part, say the Smiths, to the fact that "we gave them no reason to say no. We had free baby-sitting in the school with films and activities. We also served lunch and dinner each day, totaling 1,000 meals."

Another part of Leathers' formula is for all workers to break together for the shared meals in order to build camaraderie. The meals are cooked and served by parent volunteers.

In answer to the typical "I-can't-possibly-do-carpentry" complaint, everyone is given the same general direction: Put big nails in the big boards and small nails in the small boards.

All volunteers are divided into three-man crews with a semiskilled leader who reports to the architect for 15- to 30-minute job tasks.

"When you have your own little job all day, such as installing wooden spools, you have no idea what everyone else is doing," says Art Smith, a systems analyst. "It is amazing at the end of the day to see what has been accomplished."

A join-the-parade kind of enthusiasm builds throughout the four days, so that by the end there may be as many as 150 people working on the project at one time.

Because participation is promoted as a family affair, children are asked to bring buckets, scrub brushes and sandpaper to school for washing tires and sanding boards.

Children stay on the sidelines once power saws are used during the last two days, but Leathers has already told them, "This is your playground. You are going to design it and build it, and your parents are going to help you."