Abstract: A heat sealing station for forming closely spaced heat seals across a tube of flexible packaging material includes a set of jaws moveable between an open position where the tube is free and a closed a position where the tube is trapped between the jaws. An electrically insulating backing is carried by a first jaw of the set. A pair of closely spaced, curved resistive heat sealing bands are vulcanized onto the backing. The heat sealing bands are energizable to form closely spaced heat seals across the tube when the first jaw is moved towards the tube to bring the backing into contact with the tube and when the heat sealing bands are energized. A backing is also provided on a second jaw of the set that corresponds in shape to the electrically insulating backing.