NOTE: balsa is by far the softest and lightest wood in existance and is really in a class all its own in that regard.
BOTANICAL NAME: Ochroma spp.
Ochroma spp. of the family Bombacaceae, including at least the following: O. bicolor, O. concolor, O. grandiflora, O. lagopus, O. limonensis, O. pryamidale, O. tomentosa and O. velutina
COMMON NAMES: corcho (Mexico), gatillo (Nicaragua), enea, pung (Costa Rica), lana (Panama), pau de balsa (Brazil), palo de balsa (Peru), tami (Bolivia). Also: lanero, polak, topa
TYPE: Hardwood (and THE classic case of a "hardwood" not being hard)
COLOR: the heartwood is pale brown or reddish but the sapwood, which is what one normally means when one talks about balso, is nearly white or oatmeal colored sometimes with a yellowish or pinkish hue. It is frequently bleached for hobby use.
GRAIN: generally straight
TEXTURE: medium to coarse but the softness gives it a velvety feel
PROPERTIES / WORKABILITY: very easy to work with sharp, thin-edged power or hand tools but dull or thick-edged cutters tend to give a woolly finish. The wood is too soft to hold nails and screws but glues satisfactorily. It is low in absolute strength, stiffness, and shock resistance, although quite strong for its weight
DURABILITY: perishable; vulnerable to dry-wood termite attack; logs and green lumber are readily attacked by pinhole borers. Heartwood is resistant to preservative treatments; sapwood is permeable.
FINISH: finishes fairly well but porous composition soaks up finish.
STABILITY: extremely stable in service
BENDING: absolutely not suitable for steam bending.
ODOR: without distinctive odor or taste.
SOURCES: Widely distributed in tropical America; throughout the West Indies, and from southern Mexico, through Central America and into Venezuela, Colombia, Brazil, Ecuador (one of the most prolific sources), Peru, and Bolivia. Usually found at lower elevations especially on bottom land soils along streams; also in clearings and cutover forests. Cultivated in plantations. Also grows in Indonesia.
USES: this is the "miracle material" of the hobby world. It has the best strength-to-weight ratio of any other natural material. Known for its high strength and low density, it can be easily shaped, sanded, glued, and painted. Absorbs shocks and vibrations well and so is ideal for model-making in general and very particularly for model airplanes and model rockets.
It is also used for insulation for heat, vibration, and sound and in rafts, life belts, floats, core stock in sandwich constructions, surgical splints, toys
TREE: grows incredibly fast; an average of 60 to 90 feet tall in 6 to 10 years, with a diameter of about 2.5 to 4 feet. Slight buttresses develop in the larger trees.
WEIGHT: average about 10 pounds per cubic foot but can vary from 5 to 20 pounds per cubic foot making it one of the most, if not the most, variable-weight woods in the world.
DRYING: Kiln-drying of converted stock preferable to air-drying to minimize splitting and warping
AVAILABILITY: very readily available in hobby-use sizes