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Koa

Hawaii's hardwood soldier of the sea

Had the 18th century explorer Captain James Cook been a woodworker with an eye for fine stock, he would have shaken his head in disbelief on his first Hawaiian landing. For in that Pacific paradise, natives had for centuries depended on huge outrigger canoes made from hollowed-out logs of a brightly hued hardwood. In them, they traveled hundreds of miles from island to island for war or trade. In fact, the early Hawaiians honored their canoe wood for its seaworthiness by naming it koa-ka, meaning "valiant soldier."

The English shortened the native word to koa. And, they no doubt quickly discovered that the beautiful wood had potential for more than dugout canoes.

By the late 1800s, items of koa appeared in U.S. ports, brought by returning missionaries. Attracted by the color and figure of the new wood, furnituremakers, architects, and coachbuilders demanded logs. Nowhere, though, did anyone sing the gorgeous wood's praises louder than in Hawaii. There, craftsmen made koa ukuleles, an instrument introduced by Portuguese sailors.


Wood identification

Koa (Acacia koa) grows in quantity only in the Hawaiian islands. There, it grows everywhere--from the beaches to the volcanic peaks. Koa trees in Hawaii show no preference for a particular soil type or climate.

Mature koa trees reach 120' heights and 8' diameters. In stands, their trunks can be free of branches for 80'. Open-grown koa trees, however, nearly imitate live oak trees with numerous spreading branches that form wide, open crowns.

Koa's bark appears gray colored, flaky, and fissured. Branches display clusters of small, light-green, pointed leaves.

At about 50 pounds per cubic foot, air-dry, koa weighs about 25 percent more than black walnut. Koa, like walnut, has high crush resistance and shock absorbance. Unlike walnut, however, koa's grain interlocks, opening the door for exceptional fiddleback figure.

Koa's thin, light-colored sapwood surrounds a heartwood that some woodworkers describe as lustrous, swirled marble. Primarily reddish brown to dark brown, the wood occasionally carries colorful tones of gold, black, and deep purple.


Working properties

Due to koa's interlocking grain, you'll find that it has a greater bending strength and stiffness than walnut. It works quite easily with both hand and power tools, except that it may burn when routed or sawed cross-grain. So, keep cutting edges sharp, and avoid a slow feed rate. Plane curly or fiddleback koa at a slight angle to avoid tearing the grain.

You'll have best success joining koa with screws and glue because occasional resin pockets sometimes prevent solid adhesion with glue alone. These same resins, however, make the wood resistant to insects and fungus. And, you can sand koa to a silky finish.


Uses in woodworking

Koa ranks as a cabinet wood of exceptional beauty and quality. You can work it into fine furniture, sculpture, turnings, and musical instruments. Because of its shock resistance, it makes exceptional gunstocks. Due to its decay resistance, koa also performs well as boat trim. As veneer, especially with fiddleback figure, koa becomes costly architectural paneling.


Cost and availabilitly

In the early 1970s, koa was readily available in the mainland U.S. Then, it practically disappeared in the marketplace because Hawaii's main koa mill ceased operation. Now, through the efforts of smaller mills in the islands, you can buy the wood once again--at a premium price of about $5 per board foot. Plain-sliced, nonfigured veneer costs about $1.50 per foot--double for figured.

Illustration: Steve Schindler Photographs: Jim Kascoutas


 

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