The Butt-Buster is a device created to test the bondability of mud and the strength of tapes to see how much movement they can withstand before failure occurs.  It gauges compression and expansion in pounds and distance of movement to see how different products stand up to structural movements including environmental elements, heat, moisture, cold, etc.  Each test sample is prepared using standard installation guidelines and is placed on the Butt-Buster.  Using a crank, the sample is then pulled or compressed while the gauges measure the pounds of pressure and distance of separation until the tape fails.