Bamboo is not wood, but a grass with no woody material in its stem. But we are seeing more and more use of this grass in cabinets and as a wood substitute. And I have seen some pretty good-looking bamboo items.
Bamboo is harvested in a manner similar to trees. The round, hollow stem, with closed sections every foot or two, is sawn lengthwise into narrow strips that are then made into rectangular-cross-section pieces to take out the curvature.
Strips are edged-glued into veneer and glued into “plywood” panels that look and behave much like wood. There is a growing list of active importers bringing bamboo products to North America.
There are more than 1,000 species of bamboo. Properties and appearance vary greatly. Know your supplier well.
Bamboo is very fast growing and promises to supply fiber needs in many parts of the world where wood-based timber growing takes too long. A bamboo tree can reach 40 feet and more than 6 inches in diameter within 4 years. When harvested, the root system will send up sprouts which perpetuate the species with little human intervention. In many parts of the world, bamboo is grown in managed plantations.
The piece of bamboo in the picture consists of long, narrow strips (about 1/8 inch in thickness and 1/4 inch wide) that are edge-glued together to form the 1/8 inch surface veneer. Most people believe that bamboo is flexible and lightweight. However, bamboo products like the one pictured are actually as heavy and strong as oak.
Processing suggestions and characteristics
Properties listed are for Calcutta bamboo (Dendrocalamus strictus), which is the most common bamboo in the Indian forest.
Density: Bamboo is about 40 pounds per cubic foot, similar to oak. As bamboo panels will be 100 percent bamboo, they will be slightly heavier than an oak plywood panel of similar thickness, as most oak plywood uses a lower density species for interior plies.
Drying: Bamboo is dried at the site of manufacturing. There is little difference between radial and tangential shrinkage.
Gluing and machining: Calcutta bamboo (and many other bamboos) glues well. Surfaces must be well prepared. It may take some experimentation to determine the best glue spread rates. PUR adhesive is an excellent choice when gluing pieces of bamboo. Machining bamboo is reported to be very good, but there will be variation when the species change.
Stability: Shrinkage is 3 percent MC change resulting in a 1 percent size change and is essentially the same in the radial and tangential directions (across the grain directions).
Strength: The strength (MOR) ranges from 12,000 to 22,000 psi. Stiffness is 1.1 to 2.9 million psi, a bit higher than oak.
Want more? For more on this and other species, search the Wood Explorer collection at woodworkingnetwork.com/wood-explorer
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