Moisture-induced deformation in the neck of a classical guitar

Abstract

Abstract Classical guitar necks were submitted to 40, 65 and 80% relative humidity (RH) during time periods ranging from 24 h to several months, and moisture-induced deformations were observed. Different types of classical guitar necks were investigated in terms of structure and reinforcement. The influences of the wood species and the neck reinforcements on the moisture content (MC)-induced deformation were in focus. First, before humidity exposure in the climatic chamber, the relative positions of three points marked on each sample were measured with a control ruler and noted. After exposure, the displacement of the reference points on the samples were verified periodically. The differences between the measurements in different stages and reference positions were calculated, resulting in relative displacement data of the measured points. During the experiments, the MC of the sample was monitored by weighing. The variation of RH leads to dimensional instability and moisture-induced stresses of the guitar necks, which affect the acoustic quality of a guitar. Steel enforcement of the guitar neck improves this situation.