Surface Performance of Oak Wood Treated with Selected Oil-Based Finishing Systems

The evolving awareness related to environmental protection can be observed in all aspects of life. While making efforts to limit the use of synthetic coatings, it is necessary to find sustainable alternatives for wood surface preservation. By comparing the properties of natural substances, it is possible to determine if and to what extent they can be used as alternatives. The aim of this study was to compare the effects of tung, coconut, palm and linseed oils, as well as a commercial formulated oil-based finish, on colour change, gloss, scratch resistance, abrasion resistance and surface hardness of oak wood. Untreated wood served as a control group. The measured properties included colour parameters in the CIE Lab* space, gloss at 60° angle, scratch resistance, mass loss in the Taber abrasion test, as well as Brinell hardness. All the systems under study caused a visible darkening of the surface (ΔE*ab = 11.83–17.33). The most significant change in colour took place after the application of palm oil, while coconut oil was the only one that increased gloss. The formulated oil-based finish provided the best overall mechanical effect: the smallest increase in mass loss during abrasion, and hardness improved by 11% compared with untreated wood. The results suggest that finishing properties depend on the complete system, its curing degree and method of application, and not only the plant-based origin of the oil.