Abstract: A device for testing the strength of a glue bond of a paperboard container corner section, which section includes one wall panel adhesively secured in face-to-face relationship to a glue flap which is foldably joined to and extends at right angles from another wall panel, by determining the force required to separate the one wall panel from the glue flap.The device has a pair of platforms mounted for pivotal movement about a common axis, each carrying clamping elements for gripping one portion of a container corner section, and a load cell associated with one platform and operable to measure the force required to separate the one wall panel from the glue flap, based on the relative movement of the platforms.