The manufacture of a bio-composite acoustic guitar made from wood-PHA composites

Abstract

Rare-wood which has traditionally been used in the making of the acoustic guitar, has been the growing concerns among producers due to the environmental issue and scarcity in obtaining high-quality wood. Technological advancement had paved the way for producing musical instruments including guitars using bio-composite, bio-sourced and/or biodegradable materials. The scope of the project is to produce, manufacture and demonstrate the use of PHA polymer and wood to produce a biodegradable composite acoustic guitar whilst achieving high-quality surface finish and at the same time obtaining an insight and understanding of the wood plastic processing properties.The project’s methodology is by way of research and experiment carried out at the UQ laboratory to select the most suitable wood-PHA combination (wood fibre or wood flour with PHA). Various different compositions and combination of wood-PHA (50%-50%, 30%-70%, and 20%-80%) material samples were tested by curing it at different curing cycle to obtain the optimum melting temperature and time which is then used as the basis to produce the guitar. Besides, a study had also been done to determine the wet processing of the guitar (distilled water or ethanol) which is then used to manufacture the body of the guitar. The techniques used in this project are via vacuum bagging and oven processing.From the findings, the most suitable combination is using the wood flour and PHA and melting it at a temperature of 180oC for 20 minutes. For the wet processing of the guitar body, it is investigated that mixing the material with ethanol gives a better result than using distilled water. The body of the guitar is being cured in the autoclave with a total pressure of 2.5 bars to overcome issues with porosity as well as to gives a high-quality surface finish. The soundboard was manufactured separately with a thickness of 3 mm. The soundboard is first being hardpressed to ensure most of the air is taken out before being cured. Numerous challenges and difficulties were faced during the manufacturing process, the solutions to which were herein discussed. The primary challenges were to ensure that the material has a good vacuum and enough pressure while it’s being cured.Overall, the project is a success and has met its objectives of making the acoustic guitar using the wood-PHA composite materials with some reinforcement to address the deformation and cracking due to the lack of stiffness properties of the wood-PHA material.