Planishing Benefits: Planishing roll process machines smooth out the seam weld beads for a blended ID and OD finish on the weldment up to 40 feet long. MIG, (GMAW) TIG, (GTAW) or Plasma Weld (PAW) – any low profile weld crown can be flattened smooth. This advanced complete seamer system that can be customized for your specific welding application. This fuel tank seamer model was built for a petrol fuel tank truck length of 28 ft. Tank seam welding automation up to 40 feet of vessel seam welding length.