Particularly suitable for use with less flexible adherends for which a 180 ° peel test is not suitable because the adherends crack, break or delaminate. A bonded assembly of two adherends is prepared 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 approximately normal to the plane of the bond, through the separated part of the flexible adherend. A figure shows a schematic diagram.