Improving dimension stability of mahogany (Swietenia mahagoni) wood with oleoresin of Dipterocarpus sp as a bio-coating

Mahogany (Swietenia mahagoni) wood is widely used as furniture material. Unfortunately, it has unstable dimensions. Natural coating (bio-coating) is one alternative to improve the dimension stability of wood surfaces, such as the oleoresin of Dipterocarpus sp. The surface coating can be caused discoloration of the wood. This study aimed to determine how to improve oleoresin mixture coating for S. mahagony wood, and its color change occurred. S. mahagony wood is obtained from local sawmills under air-dry conditions. The treatment consisted of control and a mixture of oleoresin dissolved in diesel fuel with concentrations of 0%, 10%, 20%, and 30%. Dimensional stability tests can be classified according to the method used for the wood shrinkage test (ASTM D143-21), A recent study showed that a higher concentration of oleoresin mixture caused more concentration in viscosity (45.33 to 233.71 centistokes) with a decreased level of color clarity and tended to be white. Coating the oleoresin mixture on S. mahogany showed improvement in dimensional stabilization. The shrinkage from air dry to kiln dry in the longitudinal direction decreased from 3.2% to 1.73%, radial direction decreased from 8.6% to 5.12%, and tangential direction decreased from 13.05% to 11,12%. S. mahagony wood was coated with a mixture of oleoresin, which showed that the color had changed to a darker one. This present study concluded that the viscosity value increased along with the increase in wood weight and stability. Increased dimensional stabilization occurs in many directions of wood cutting. The degree of swelling and shrinkage of wood in the longitudinal direction was lower than in other logging directions, while the color had also changed to darker than others. As an alternative to bio-coating, oleoresins provided mahogany with valuable materials for better natural dimensional stability.