Welding HDPE (high-density polyethylene) plastic sheets is a common connection method, widely used in water tanks, chemical equipment, floor protection, livestock facilities and other fields. Due to its high thermoplasticity and chemical inertness, HDPE is suitable for a variety of thermal welding methods. The following are the most commonly used welding techniques and operation guidelines:
I. Common welding methods
- Hot air welding
Suitable for plates with a thickness of 3mm to 10mm, with high welding accuracy.
Required tools:
Hot air welding gun (temperature-controlled, adjustable temperature)
HDPE welding rod (diameter 3-5mm)
Welding nozzle (flat or round)
Roller pressure plate, cleaning tool, scraper
Steps:
Prepare the sheet surface: clean the weld area and grind it rough (80-120 grit sandpaper is recommended).
Preheat the welding gun: set the temperature to 260°C to 300°C.
Insert the welding rod: feed the HDPE welding rod from the welding gun nozzle.
Uniform movement: Hold the welding gun and move slowly and uniformly along the weld, while pressing the welding rod with a roller.
Cooling inspection: Check the weld after natural cooling to ensure that there are no bubbles, burns, or desoldering. - Extrusion welding
Suitable for thick plates (more than 10mm) or connections with high structural strength requirements.
Required equipment:
Plastic extrusion welding gun (with screw heating system)
Welding rod (HDPE raw material strip)
Electric heating plate or hot air preheating
Features:
Melted HDPE is directly extruded into the weld;
Fast welding speed and high strength;
Commonly used for structural parts such as water tanks, troughs, and guard walls. - Butt welding / hot plate welding (Butt Welding)
Suitable for large-area splicing of thick plates, such as pool bottom plates, fences, etc.
Tools:
Hot plate welding machine (automatic/semi-automatic)
Clamping device or clamp
Steps:
Heat two HDPE plates to 210–230°C;
Contact the hot plate to soften it;
Remove the hot plate and quickly press the two plates together;
Cool under pressure to ensure a smooth connection.
II. Precautions
Item Recommendation
Surface preparation Keep the weld clean and dry, without oil stains
Welding temperature between 260–300°C, too high will easily burn, too low will not stick firmly
Welding rod selection Same material (HDPE) and dry to avoid water absorption affecting quality
Environment Avoid strong wind and dust, it is recommended to operate at room temperature
Cooling time The cooling time of the weld should be ≥10 minutes, and forced cooling (such as water flushing) is prohibited
Post-welding inspection method
Appearance inspection: The weld should be uniform, without bubbles, blackening, or cracks;
Tapping method: Tap the weld with a small hammer, and the sound indicates that the weld is firm;
Strength test: Tensile test (if feasible) to observe whether the break is in the weld.