HDPE Geomembrane Tips: Welding

From small-scale fish/shrimp farming to mega-landfill projects, geomembranes are the indispensable solution wherever waterproofing and seepage control are required. However, achieving optimal performance hinges critically on the welding process.

Welding joins individual geomembrane rolls into continuous barriers, raising two vital questions: What if leaks occur at seams? How to ensure equivalent waterproofing at welded joints? This requires two essential machines: Dual-Track Hot Wedge Welder for primary welding & Extrusion Welding Gun for post-construction repairs.

Six-step construction sequence as follow:

1. Subgrade Preparation: Leveling and compaction; removing sharp debris
2. Material Deployment: Manual/mechanical unrolling; wrinkle elimination; temporary anchoring
3. Edge Overlap: 10cm overlap width; surface cleaning; pre-compression
4. Pre-heating and Welding: Temperature-controlled heating; dual-track welding; sealed air channel formation
5. Pressure Testing: Air-injection testing; extrusion repairs if leaking
6. Quality Certification: ID labeling; data recording; digital archiving

Moreover, the welding process imposes stringent requirements on four critical parameters: surface cleanliness, material flatness, machine temperature control, and welding speed.

1. Contaminated surfaces bring compromised strength

   Landfill case: Oil residue reduced weld peel strength to 18N/mm ( ≥40N/mm in standard), causing leachate leakage within 2 years.

2. Subgrade irregularities risks

   Stress concentration causes localized tearing.

   Voids at overlaps causes false welding.

   (ASTM D6992: Every 1mm wrinkle height ↓ fatigue life by 35%)

3. Temperature deviation causes material degradation

   < 400°C: Incomplete molecular fusion

   > 480°C: Antioxidant decomposition (OIT plunge)

4. Uncontrolled speed causes uneven fusion

   Too fast: Insufficient dwell time means inadequate penetration, bringing delamination risk.

   Too slow: Prolonged heat exposure means HAZ expansion, bringing material degradation.

Consequenctly, inadequate preparation causes necessary repairs, which means secondary environmental contamination and extra cost. How To Weld Correctly is the most important part in the whole procedure.

Contact us for quotation!

Sichuan Zhonglong Environmental Protection Co, Ltd.

Tel: +86 173 8021 9980

📬Email: sichuanzhonglong@163.com

🌐Website: https://www.zhonglonggeo.com