Ulay, GokselAkter, MeteCakicier, NevzatAyata, Umit2026-09-012026-09-0120260169-42431568-5616http://dx.doi.org/10.1080/01694243.2026.2675489https://hdl.handle.net/20.500.12403/8511This study evaluated the effects of different weathering durations (168, 336, and 504 h) on surface hardness and adhesion strength of both heat-treated (1.5 h at 190 degrees C and 2 h at 212 degrees C) and untreated iroko (Chlorophora excelsa) wood surfaces after application of water-based varnish (WBV). Pendulum hardness (s) and pull-off adhesion (MPa) tests were performed after weathering. According to the results, in the untreated control group, hardness increased from 30 s to 45 s after 504 h of weathering, showing a 48% increase. In the samples treated at 190 degrees C, hardness increased from 25 s to 41 s after 504 h, showing a 61% increase. The highest increase was observed in the samples treated at 212 degrees C. Here, the hardness increased from 23 s to 44 s, representing a 91% increase after 504 h of weathering. The highest initial surface adhesion strength (5.30 MPa) was obtained in the unheated samples; however, this value decreased significantly after weathering. Although the initial adhesion strength was lower in the heat-treated samples, those treated at 212 degrees C for 2 h exhibited more stable weathering performance. The results show that the acceleration of weathering and the application of heat significantly affect the effectiveness of the varnish coating.eninfo:eu-repo/semantics/closedAccessIroko WoodAccelerated WeatheringPendulum HardnessPull-Off Adhesion TestingWater Based VarnishArticle10.1080/01694243.2026.26754892-s2.0-105039962720Q2WOS:001776046100001Q2