An overview is given over various methods applied for testing of the bond strength across the extrusion weld obtained in hollow extruded Al-profiles. A new method has been invented to be used for this purpose. The mechanical characteristic of the method is described. Various applications of the method are also described. A case is presented where a contaminant film is observed to flow into the extrusion weld so that extrusion weld quality becomes lowered due to the presence of this film. The degree of reduction of weld quality in this case is quantified by the new test method.