Balsa

Uses

Balsa wood is very soft and light, with a coarse, open grain. The density of dry balsa wood ranges from 40 to 475 kg/m (2.5 to 29.7 lb/cu ft), with a typical density around 160 kg/m (10 lb/cu ft). Balsa is the softest wood ever measured using the Janka hardness test (22 to 167 lbf (98 to 743 N)). 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, which 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.