Document Type

Article

Publication Date

3-10-2026

Department

College of Forest Resources and Environmental Science

Abstract

The objective of this study was to explore the effect of selected gluing parameters such as different wood surface temperature and equilibrium moisture content (EMC), the use of primer, and pressing pressure and duration, on the bondline quality of Norway spruce (Picea abies). Eight various combinations were evaluated for gluing spruce samples using commercial 1-component polyurethane adhesives and compared with control boards that were bonded at standard conditions of 12% EMC, 20°C surface temperature, 0.6 MPa pressing pressure and 75 min pressing duration. Tensile shear strength tests were conducted in accordance with the EN 302-1:2023 standard and revealed a negligible effect of EMC on the bonding strength, while highlighting the pronounced role of pressing pressure. The presence of primer offset the lower surface temperature by providing comparable tensile shear strength to that of the control samples. The microscopic observation of the bondline showed that at lower pressing pressure, adhesive penetration into the wood was limited, leading to low interfacial bonding and formation of voids in the bondline. However, increasing the duration of applied pressure or the application of primer under non-standard bonding conditions resulted in better bondline formation and adhesive penetration, as reflected by the comparable bonding strength to the control samples.

Publisher's Statement

© 2026 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Publisher’s version of record: https://doi.org/10.1080/17480272.2026.2640494

Publication Title

Wood Material Science and Engineering

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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