Steam Bending of Wood; Embellishments to an Ancient Technique

Robert S. Wright, Brian H. Bond, Zhangjing Chen

Abstract


Bending wood dates back to antiquity in the form of baskets from willow branches. Fresh growth willow twigs are readily bent into practically any shape. When wood has been separated from the tree and dried it is more rigid, difficult to bend, and breakable. Bending drier wood with the help of heat and water is centuries old. Fishing hooks, barrel staves, and planks turned into boat hulls are examples. Steamed wood is less rigid, since adding moisture and heat to wood results in plasticization. Steaming at atmospheric pressure is common, wherein diffusion prevails as the predominant mechanism governing moisture movement. Applications using conventional atmospheric steaming can be time consuming, non-uniform, and can result in failures. Vacuum steam technology offers a promising method that utilizes pressure differentials to accelerate the addition of steam to wood due to water vapor bulk flow and subsequently an accelerated temperature rise. More uniform plasticization results in less breakage of the wood.

Keywords


Steam bending; Wood; Plasticization; Vacuum steam technology (VST); Diffusion; Water vapor bulk flow; Luthier

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Welcome to BioResources! This online, peer-reviewed journal is devoted to the science and engineering of biomaterials and chemicals from lignocellulosic sources for new end uses and new capabilities. The editors of BioResources would be very happy to assist you during the process of submitting or reviewing articles. Please note that logging in is required in order to submit or review articles. Martin A. Hubbe, (919) 513-3022, hubbe@ncsu.edu; Lucian A. Lucia, (919) 515-7707, lucian.lucia@gmail.com URLs: bioresourcesjournal.com; http://ncsu.edu/bioresources ISSN: 1930-2126