Wood is what you use to build houses. Plastic and composite fibers are what you use to make planes.

What could you possibly make by combining the two?Researchers around the country are trying to answer that question. They're studying how to combine two seemingly incompatible materials into products that are lighter, stronger but use less wood than what's available now.

Among the projects:

- Two University of Washington mechanical engineering professors are studying how to combine wood and composite fibers in new building materials.

The research project may be underwritten by Weyerhaeuser Co. and Toray Composites America Inc., which is producing carbon fibers for the new Boeing 777.

- At Oregon State University, a researcher is looking at putting a layer of carbon fiber between two pieces of wood to produce reinforced beams. One potential application is in bridge construction.

- Researchers at the U.S. Forest Service's Forest Products Laboratory in Madison, Wis., are studying how to combine recycled wood and recycled plastics to make a material that could be molded and shaped for dozens of uses such as furniture or automobile interiors.

- Louisiana-Pacific Corp. has purchased a California manufacturer of storage units for compact discs and videotapes. Louisiana-Pacific is interested in Creative Point Inc.'s expertise in plastics to develop new building materials.

This flurry of research activity is driven by two forces: the strength and flexibility of new materials like carbon fibers and the expected shortage of traditional supplies of wood.

"Almost everybody in the industry assumes that traditional wood products will be too difficult to produce," says Louisiana-Pacific spokesman Barry Lacter.

"L-P, like other companies, is looking at how to combine with other resources that are affordable and don't require the timber resource that's hard to come by," he said.

Combining wood and plastic isn't a new concept. Weyerhaeuser used to produce a material known as PreStock that combined wood fibers and polypropylene into mats that were used in car panels.

What is new is the potential for structural building materials. In glued laminated beams, for example, using composite fibers means "you can use a lot less high-quality (wood) material, yet you get a much higher strength characteristic," says Tom Williamson, executive vice president of the American Wood Systems division of the American Plywood Association. "You can compete with steel."

The wood systems division is among those taking a look at the new materials.

Minoru Taya, mechanical engineering professor at the University of Washington, says engineered wood products can increase the stiffness of a conventional 2-by-10 or 2-by-12 beam by 40 percent. Taya believes a composite materials beam could be two to three times more rigid than a board cut from a log. That would allow beams to span longer distances.

The catch is that composite fibers aren't cheap, particularly if they're being used as a layer in a wood sandwich. Any product can be reinforced with non-wood material, Williamson says. But the cost has to be balanced by increased strength and other characteristics, he says.

Researchers believe they can find ways to cut the costs, perhaps by using less-expensive composite fibers. "There really is a lot of momentum building," Williamson says.

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Additional Information

A guide to engineered wood products

Just what is this stuff anyway? A quick guide to some of the types of engineered wood products and the techniques for making it:

- Plywood - The original engineered wood product. Thin sheets or "veneers" of wood are peeled from logs, then glued together; the grain of each layer is perpendicular to the grain of the layers above and below.

- Oriented strand board - The new generation of panel; odd-shaped flat chips are laid flat, coated with resin and fed into a hot press to create a board. - Laminated veneer lumber - Veneers of lumber are laid on top of one another with the grain all running the same direction and glued together. This veneer sandwich is then sliced into boards.

- Glued laminated beams - Smaller boards are glued face-to-face to make thicker beams.

- Parallel strand lumber - Irregularly shaped veneers are sliced into rulerlike strands, coated with resin, funneled into a press and zapped with microwaves, producing a solid postlike piece of wood that can be sawed into boards.

- Oriented strand lumber - Long thin strips of wood are sliced from logs, coated with resin, then steamed and pressed into billets.

- Wood I-joist - A combination of engineered wood products. The caps of the I-beam are made from laminated veneer lumber; the midsection is made of oriented strand board. Used mainly for floor supports.

- Medium-density fiberboard - Wood fibers mixed with resin are compressed into boards.

- Scrimber - An Australian technology being tested by Georgia Pacific. Logs from young, fast-growing trees are stripped of bark and crushed between rollers, then pressed into large blocks for sawing into lumber.