Balsa lumber is very soft and light, with a coarse, open grain. The density of dry balsa wood ranges from 40–340 kg/m^3 (2.5–21.2 lb/cu ft), with a typical density of about 160 kg/m^3 (10 lb/cu ft). The wood of the living tree has large cells that are filled with water. This gives the wood a spongy texture. It also makes the wood of the living tree not much lighter than water and barely able to float. For commercial production, the wood is kiln-dried for about two weeks, leaving the cells hollow and empty. The large volume-to-surface ratio of the resulting thin-walled empty cells gives the dried wood a large strength-to-weight ratio because the cells are mostly air. Unlike naturally rotted wood, that soon disintegrates in the rainforests where balsa trees grow, the cell walls of kiln-seasoned balsa wood retain their strong structure of cellulose and lignin.

General Applications: Cores for sandwich structures; model building; floatation; insulation.

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Record number: 1103