Suitable for use with less flexible adherends. The principle consists in preparing a bonded assembly of two adherends, using the adhesive under test. The adherends are then pulled apart at a steady rate, starting at the open end of the bond, in such a way that separation occurs progressively along the length of the bonded adherends. The force is applied substantially parallel to the plane of the bond, through the separated part of the flexible adherend. A figure shows a schematic diagram.