Santos mahogany: Strong, hard, resinous wood from South America

Santos mahogany (Myroxylon balsamum) is also called balsamo (English) and palo de balsamo (Central America) in the lumber business. Although this wood is not related to Honduran (or true) mahogany or to African mahogany, it is a rich, dark mahogany colored wood and is actually a bit harder than Honduran mahogany. The wood has an interlocked grain, which gives it a strong ribbon-like pattern.

The tree, which is in the legume family, is widespread, ranging from southern Mexico southward through Central American and continuing down to Argentina. Trees are usually short, 50 to 65 feet tall, and moderate in diameter, 18 to 36 inches. The typical log produces a large amount of knot-free lumber.

This tree is well known for the resin, called balsam or balsamo, that it produces. In fact, 16th century Spanish explorers shipped balsamo to Europe, where it was claimed to have extravagant medicinal properties. Indeed, the resin has a spicy aroma, somewhat similar to vanilla. Much of today’s resin production comes from El Salvador, although plantings in Africa and Southeast Asia are now producing this resin as well.

Today, the resin is used in salves, cough syrup flavorings and perfumes. When tapping the tree for the resin, in the past it required the bark to be scored deeply, and the tree was severely injured and died. As a result, the old-growth availability of this excellent wood is quite limited, although it has been recently planted in plantations.

The hardness of this wood makes it ideal for flooring, although it is also sometimes used for furniture, interior trim, and turnery.

Processing suggestions and characteristics
Density. The density is quite high (around 60 pounds per cubic foot). A board foot of planed lumber (15/16 x 12 x 12 inches) will weigh about 4-3/4 pounds; roughly 30 percent heavier than oak.

Drying. Shrinkage from green to 7 percent MC is only 4.6 percent tangentially (width) and 2.8 percent radially (thickness), which are low values for a wood of this high density.

Gluing and machining. The high density and some oiliness make this somewhat difficult to glue with standard woodworking adhesives, but not as difficult as teak or other resinous woods. Surfaces should be prepared and glued within 15 minutes to achieve the best joint strength. It is reported to be moderately difficult to machine; sharp tools and fresh sandpaper are essential for premium surfaces.

Stability. The wood is exceptionally stable when exposed to humidity changes. It would take a 6 percent MC change to result in a 1 percent size change tangentially and 10 percent MC radially.

Strength. The MOR is 20,100 psi; the stiffness (MOE) is 2.4 million psi and the hardness is 2,200 pounds. For comparison, red oak values are 14,300 psi, 1.8 million psi and 1,290 pounds. Because of the density, all nails and screws must use pre-drilled holes.

Color and grain. Santos mahogany exhibits a range of color between light orange/brown with yellowish overtones to a dark reddish/purplish brown. The interlocked grain gives a striped appearance especially on quartersawn grain. Overall, the grain is tight and fine textured, with a natural luster after machining and sanding.

 

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About the author
Gene Wengert

Gene Wengert, “The Wood Doctor” has been training people in efficient use of wood for 45 years. He is extension specialist emeritus at the University of Wisconsin-Madison.