Dynamic behavior of microwave-cured guitar wood

An ongoing investigation has been conducted to measure and analyze vibration properties of guitar-body wood samples with different wood finish curing methods for Taylor Guitars. The current method uses ultraviolet radiation to cure a lacquer finish. Virginia Tech's (VT) Material Science & Engineering Department has proposed an alternative method using microwave radiation to cure the finishes, now in its third stage of development. Microwaves (MW) have longer wavelengths than ultraviolet (UV) radiation, allowing greater penetration depth and increased diffusion between wood and lacquer molecules. To investigate the effect of the finish on dynamic behavior, modal analyses have been conducted at the University of Hartford Acoustics Engineering Laboratory using unfinished, UV-cured, and MW-cured guitar wood samples (spruce, maple, ash, and rosewood). Samples were characterized at bending and torsional modes up to 3.2 kHz. Overall results to date demonstrate that both UV-cured and MW-cured samples have higher damping than unfinished samples. Further, the damping provided by the MW method appears to correlate with the number and thickness of filler, finish and top coats. The current results suggest it is possible to produce similar dynamic behavior to UV curing using the MW technique. [Work done in collaboration with Virginia Tech and Taylor Guitars.]