MATERIALS FOR GUITAR BACK PLATES MADE FROM SUSTAINABLE FOREST RESOURCES

A new type of wood-based material for guitar back plates as a substitu te for Brazilian rosewood was produced based on Japanese cedar logs wi th a small diameter, of which the utilization is limited despite its a vailability. The sapwood portion of logs with a diameter of 20 cm was processed to veneers of 2 mm thickness using a rotary lathing machine. The veneers were impregnated with a low-molecular-weight phenolic res in, laminated in parallel, and compressed perpendicular to their plane . When the veneers were treated with a 3% or 5% aqueous solution and c ompressed to a density of 0.8 without adhesives, the specific dynamic Young's modulus (E/gamma, ratio of stiffness to specific gravity) and tan delta (damping) of the materials became almost the same as those o f Brazilian rosewood in the lower-frequency range, not only in the lon gitudinal direction but also across the longitudinal direction. Howeve r, the frequency dependencies of the specific Young's modulus and tan delta of the materials differed from those of Brazilian rosewood, whic h may be partially related to the higher values of E/G of laminated co mpressed wood as a result of the increased density induced by deformat ion of the cell walls. (C) 1997 Acoustical Society of America.