Extrusion Welding

Extrusion welders are larger and heavier welders that use a plastic welding rod forced down a heated barrel by an internal screw. The welding rod is softened and mixed in the heated barrel, and is then pushed out as a molten bead of plastic directly onto the geomembrane liner. This molten bead of material is shaped by a Teflon shoe over the edge of the overlapped materials. Hot air is blown into the overlap ahead of the molten plastic in order to soften the material to form a stronger weld. The welding rod used by the extrusion welder must be selected to be compatible with the geomembrane, often being manufactured from the very same resin batch.
This style of welding is largely restricted to HDPE, Polypropylene and LLDPE materials as the likelihood of material degradation in the heated barrel makes this welding technique unsuitable for PVC or Urethane based geomembranes.