Because of its strength and light weight, balsa wood is most commonly used in making models of structures, such as bridges, buildings, boats and aircraft. The use of balsa wood is common in model airplanes, especially radio-controlled free-flying aircraft.
Balsa trees grow in the rain forests of Central America and South America. Once considered a weed tree, balsa trees grow very rapidly. They can reach their full height of 60 to 90 feet within six to 10 years.
The balsa’s light-weight density stems from the way the cells are structured in the wood. Instead of having a condensed cell full of a fibrous material called lignin, the balsa tree’s cells are stretched thin and contain less lignin. When alive, the tree gets its strength to stand by pumping water into the tree’s cells until they become rigid. When the tree is harvested, the wood is kiln-dried to remove all its water weight.
Model airplanes use a wood weight that is between 6 and 18 pounds per cubic foot. The wood is easily shapeable; extreme enthusiasts typically only use X-ACTO knives to cut and carve the wood. Hobbyists need to learn the different types of grain in the wood before starting a project, as the grain impacts the strength and flexibility of the wood within the design.