Abstract: A lifting magnet has lengths of sealed plastic tubing positioned circumferentially of its coil prior to its encapsulation in a magnet case. The tubing is hermetically sealed every few inches along its entire length in order to divide the tubing into individually sealed segments. The sealed segments form compressible air spaces at the outer periphery of the magnet coil which permit thermal expansion of the coil and the encapsulating material without substantial force being applied by the coil and the encapsulating material to the magnet case. In the event any one or a few segments of the tubing are perforated or otherwise disabled in the course of fabrication or assembly of the magnet, the balance of the sealed segments still serve their intended purpose.