Wood of the Week-Padauk

Botanical Background:

There are three species of trees that produce wood that we call padauk--Burma padauk, Andaman padauk (named for the Andaman Islands where it grows), and African padauk. All are legume family and have the Latin names of Pterocarpus macrocarpus, Pterocarpus dalbergioides, and Pterocarpus soyauxii

Common names include: Barwood, Comwood, Corail, African Coralwood, Muenge, Mututi, Ngula, Vermillion, Mai Pradoo, Pradoo, and Yomo.

Variation:

African padauk is found in central and tropical West Africa; common in dense equatorial rain forests, often in small groups. The Burmese variety is rather common in the upper mixed and dry forests of Burma; also found in mixed deciduous forests of Thailand.

Padauk heartwood is a vivid reddish orange when freshly cut, darkening to reddish- or purple-brown or black over time, with a straight to interlocked grain and relatively coarse texture. The sapwood is cream-colored, very uniform in color, 4 to 8 in. wide, whitish to brown yellow.

The African tree reaches a height of 100 to 130 ft, bole straight, cylindrical, and clear to 70 ft; trunk diameters 2 to 4 ft, sometimes to 5 ft. The Burmese tree is a medium-sized tree, up to 80 ft in height, boles clear to 25 ft straight and cylindrical, sometimes irregular; trunk diameters 2 to 3 ft.

African Padauk has a shrinkage rate of : 3.3% radial; 5.2% tangential; and 7.6% volumetric. Movement in service is very small. Burmese variety shrinks slightly more: 3.4% radial; 5.8% tangential; 8.4% volumetric. In terms of density, African padauk can be quite variable. It's specific gravity rangesfrom 0.55 to 0.67, but the Burmese species, with and average specific gravity of 0.75, is noticeably much harder and heavier. The Andaman species is now so scarce it is seldom seen on the international market, but it is perhaps the nicest of the padauks. With an average specific gravity of 0.63, it is more comparable to the African variety, but finer textured and even more stable. Its shrinkage, green to ovendry, is: 3.3% radial; 4.4% tangential; 6.4% volumetric."

Working Characteristics:

Padauk wood machines easily, but requires a slow feed rate and sharp tools; carbide tooling is recommended. Machined cuts are smooth, but there can be some tearing of the interlocked grain.

It sands satisfactorily, and can achieve a high sheen with high grit sandpapers. The fine sanding dust does tend to load the sandpaper, though it can be cleaned from the sandpaper with a blast of compressed air. It does not gum up sandpaper like many oily exotic woods. Most texts on padauk state that it has a faint, somewhat spicy odor. I find the odor very pronounced, though not unpleasant. The dust is a strong nasal irritant (at least to me). The dust from sanding is exceedingly fine, and if padauk is used in a mixed wood project, care should be taken to keep it from staining the other wood. Padauk’s color tends to bleed when most any solvent, including water is used. For this reason, wet sanding of mixed wood projects including padauk is not recommended without first sealing the other woods. Flat work made of padauk takes well to a cabinet scraper, though curved work and turning can exhibit tearout.

Padauk exhibits good nail, and screw holding ability, and glues well with all common woodworking glues.

Padauk finishes well; some have found that water-based finishes hold the color better, and one should consider UV inhibitors in any finish used, to reduce the darkening of beautiful reds and oranges to a dark purplish-brown.

The heartwood is resistant to termites. The sapwood is susceptible to infestation by powder post beetles. The heartwood displays excellent weathering properties.

Commercial uses include: Fine joinery, fancy turnery, carvings, flooring, decorative veneer, decorative carvings, and tool/knife handles.