The fracture moment of corner joints bonded by different glues

The main goal of this research is to determine the most appropriate adhesive to fix angular joints with wooden ring for manufacturing window frames. The joint with wooden ring is the result of Slovenian experience and is protected by international patent. The destructive strength of angular joints adhered with different glues was tested by the tensile-testing machine. Polyvinyl acetate glue of the D3 group was found to be the most appropriate from the point of view of strength. The biggest advantage of using a joint with wooden ring lies in the possibility of manufacturing wooden frames from finished elements. In this way, the process of manufacturing a window ends after assembling its parts. It is, therefore, very important to choose the right glue that can completely fill the junction and cover the whole unprotected front part of the joint. For this purpose, polyurethane glues were used in the experiment, as they slightly expand during the hardening phase.