Wood stabilisation using methyl methacrylate polymerisation in the context of musical instrument making
摘要
This paper investigates the potential of wood stabilisation techniques in improving the mechanical and acoustical properties of temperate wood species to make them suitable for musical instrument making. Many instruments or parts are usually made with tropical woods, specifically woodwind instruments and fingerboards of chordophones. For these applications, the wood must be stable, with low porosity and good machinability. The increasingly strict regulations on international trade of vulnerable species reduce the availability of such species. Therefore, a wood stabilisation process using methyl methacrylate impregnation is proposed, focusing on these specific domain criteria. This aims to achieve properties approaching those of African blackwood (Dalbergia melanoxylon) used for clarinet and oboes, and African ebony (Diospyros crassiflora) used for chordophones fingerboards. Ten different temperate wood species and six specimens (tubes) per species were tested with this process. The Shore-D hardness, hygroscopic behaviour of wood through roundness, moisture exclusion efficiency and anti-swelling efficiency, the acoustic loss factor of the cavity and the density of samples were compared before and after stabilisation. The results suggest that hornbeam (Carpinus betulus), maple (Acer spp.) and beech (Fagus sylvatica) can be used as stabilised materials, for several applications, with improved properties. Generally, the density and hardness are significantly improved and acoustic loss factors and swelling are reduced, to reach values suitable for instrument making, whilst not reaching absolute values of tropical reference woods.