Determination of pendulum hardness (KÖnig method) values against artificial weathering in water-based varnishes applied to some wood species after heat treatment (thermowood)

Scots pine, beech, and oak are the most important tree species in the furniture sector in Turkey. In this study, the aim is to determine pendulum hardness (König method) values against artificial aging in water-based varnishes applied to some wood species after heat treatment. For this purpose, Scots pine (Pinus sylvestris L.), sessile oak (Quercus petreae L.), and Eastern beech (Fagus orientalis L.) wood samples were heat-treated at 190 °C for 2 h and at 212 °C for 1–2 h according to the ThermoWood method. Later, one-and two-component water-based varnishes (WBVOne-Comp. and WBVTwo-Comp.) were applied to the material surfaces in accordance with the manufacturer’s recommendations for layer thickness for industrial applications. The materials were exposed to UV light using UV-A 340 nm fluorescent lamps for 144, 288, and 432 h in a QUV accelerated weathering tester. After these weathering periods, pendulum hardness values were determined. It was found that hardness values increased after weathering, and that WBVTwo-Comp. gave higher values than WBVOne-Comp..