Modification of wood acoustic, hygroscopic and colorimetric properties due to thermally accelerated ageing

A mild hygro-thermal treatment was applied to wood, as a first step of pre-treatment/coating systems for musical instrument making. Longitudinal (L=150 x R=12 x T=2.5 mm) and radial Spruce specimens (R=150 x L=12 x T=2.5 mm) were trated in reactors maintained at a temperature of 130 or 150°C, and a relative humidity (RH) of 0% or varying between 0% and 25%. Weight loss (WL), equilibrium moisture content (EMC), density (p) and vibrational properties in bending (E/p, tand), were measured before and after treatment, while colour parameters were recorded also at intermediate steps.