Balsa
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| Ochroma pyramidale (Cav. ex Lam.) Urb. |
Balsa (Ochroma pyramidale, synonym O. lagopus) is a large, fast-growing tree that can grow up to 30 m 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 (30–50 cm) 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 100–200 kg/m³, with a typical density of about 140 kg/m³ (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 Chevrolet Corvette bodies tub. In table tennis blades, a balsa layer is typically sandwiched between two pieces of thin plywood.
Despite being very soft, balsa is classified as a hardwood, the softest commercial hardwood.
[edit] References
- Species description
- Germplasm Resources Information Network: Ochroma pyramidale
- Photo of foliage and flower
- Kon-Tiki museum website
- Balsa rafting in Ecuador
- Table Tennis Balsa Blades
 Three different sizes of balsa wood used for hobby purposes |
 Frame of a model airplane constructed entirely of balsa wood |
