Abstract: The making of a tubular sleeve of thermoplastic material wherein a strip of sheet stock is fed to a rotatable turret having a plurality of rotatable mandrels thereon, the strip is severed into individual rectangular blanks, each having a leading edge and a trailing edge, each blank is formed into a cylindrical shaped sleeve wrapped around a mandrel with the trailing edge overlapping the exterior of the leading edge of the blank, the mandrels are moved past a sealing station and a plurality of bars are rotated so they move successively in an arcuate path generally tangentially to the path of the blank to bring the sealing surface of each bar into engagement with the overlapped edges and apply radial pressure thereto to fuse the edges together and form a seam.