Inno-GeosynHDPE Geomembrane Welding: Hot Wedge vs Extrusion
A geomembrane liner is only as good as its seams. In the field, HDPE panels are joined by two thermal welding methods — here's what each does best, and how quality is verified.
Hot wedge welding: the production workhorse
A heated wedge travels between overlapped panels, melting both surfaces while pressure rollers fuse them — producing a dual-track seam with an air channel between the tracks. It's fast, consistent, and used for the long straight seams that make up most of a liner's area.
Extrusion welding: the detail specialist
An extruder lays a bead of molten HDPE over the seam area. It's slower but far more versatile: patches, repairs, corners, pipe penetrations and T-joints — anywhere the wedge machine can't go. Every hot-wedge seam's ends and defects get finished by extrusion.
Proving the seam: QA testing
- Air channel test — pressurize the channel between dual tracks; pressure drop indicates a leak. Non-destructive, tests 100% of wedge seams.
- Vacuum box test — soapy water plus vacuum over extrusion seams; bubbles reveal defects. Non-destructive.
- Peel & shear tests — cut samples from trial and production seams, pulled in a field tensiometer. Destructive, done on a sampling basis.
- Spark testing — for detecting pinholes in some applications.
What this means for buyers
Good resin and correct thickness are only half the story — installation quality decides liner performance. When comparing suppliers, ask about recommended seaming parameters and whether they can connect you with experienced installation crews in your region. We support our distributors with welding guidelines for every geomembrane shipment.