Balsa

Balsa — Balsa (Ochroma pyramidale, synonym O. lagopus) is a large, fast-growing tree that can grow up to 30m (100ft) tall, native to tropical South America north to southern Mexico. It is evergreen, or dry-season deciduous if the dry season is long, with large (30¨C50 cm, 12-20 in) weakly palmately lobed leaves. The name balsa derives from Spanish for a raft.

The timber is very soft and light with a coarse open grain. The density of dry balsa wood ranges from 100¨C200 kg/m0…6 (3.12-6.24 lb/ft0…6), with a typical density of about 140 kg/m0…6 (8.74 lb/ft0…6) (about one third the density of other kinds of hard wood). This makes it a very popular material for model building and buoyancy materials (lifebelts, etc.), and was famously used by Thor Heyerdahl in his raft Kon-Tiki. It is also a very popular material to use when making wooden crankbaits for fishing, as it is low density but high in strength. Balsa wood is used to make very light, stiff structures in model bridge tests and for the construction of light wooden aeroplanes, most famously the World War II de Havilland Mosquito. It also is used in the floorpan of the Chevrolet Corvette Z06 sandwiched between two sheets of carbon fibre. In table tennis blades, a balsa layer is typically sandwiched between two pieces of thin plywood.Balsa wood is also used for making high-quality balsa surfboards.

Despite being very soft, balsa is classified as a hardwood, the softest commercial hardwood.