Koa

Koa (Acacia koa)

Description

A hard, golden-brown wood from the Hawaiian acacia tree, Acacia koa. The color and grain pattern of koa wood changes with growing conditions and tree age. The lightweight, but durable wood is brittle with variations in density. Koa is difficult to work or plane but carves well and polishes to a high gloss. It was the royal wood of the native Hawaiians and was used for everything in contact with the royal family. Koa is used for carvings, boats, dugout canoes, early surfboards, veneers, musical instruments, and furniture. A Tannin extracted from the bark has been used for processing Leather.

Synonyms and Related Terms

Acacia koa; black koa; curly koa; figured koa; Hawaiian mahogany; koaia; koa-ka; round log koa; square log koa; kaolaunui

Physical and Chemical Properties

• Koa wood fluoresces in ultraviolet light.
• Specific gravity = 0.53 (green); 0.49 (dry).
• Resistant to insects and fungi.
• Color is variable; usually golden to reddish brown with some contrasting bands of color
• Grain is slightly interlocked or wavy with a coarse to medium texture.
• Koa is susceptilbe to insect attack

Working Properties

• Easy to work, and sands well
• Some figured pieces can be difficult to plane or machine without tearing or chipping of the grain
• Koa can occasionally give problems in gluing, though this is somewhat uncommon
• Koa turns, stains, and finishes well

Resources and Citations

• The Wood Database: Koa

• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• Website address 1 Comment: www.si.edu/cal/acacia_koa.html