The results show that the surface pre-treatment significantly influences the bonding strength. Nevertheless, also the kind of adhesive and the wood species have to be taken into consideration. Sanding of wood surfaces prior to bonding with KPVAC adhesives resulted in higher bonding strength values after all storing series compared to finished surfaces. Obviously, these types of adhesive better adhere to a rough surface than to a smooth one. When using a KPUR adhesive this phenomenon only applied for dry bonding strength whereas for the wet bonding strength the values reversed. Here, surely other binding mechanisms are important. By its surface structure and its substances the wood species also influence the bonding strength, the types of adhesive used also playing a dominant role.
