An apparatus for fabricating a flexible cylinder from multi-ply flexible web material has a cylindrical forming cavity with a longitudinal opening through which the flexible web material is fed into the cavity. A non-metallic cylindrical mandrel, about which the flexible web material is fed, is mounted along the central axis of the cavity. The diameter of the mandrel is less than the diameter of the cavity in which it is disposed by an amount greater than the thickness of the web material. The web material is fed loosely around the mandrel by a feed roller to form a flexible cylinder having an internal diameter greater than the diameter of the mandrel and an outer diameter less than the internal diameter of the cavity. The amount of web material fed is enough to form a narrow longitudinal overlap zone which is heat sealed to form a longitudinal seal.
A seam presser holds the overlap seam during sealing and subsequent cooling. Finally the finished cylinder is slid from the mandrel and thereby removed from the cavity.