Poly Welding

Butt Fusion Welding is commonly used to join high-density polyethylene (HDPE) pipes. This method requires appropriate temperature, time, and extreme pressure to ensure a sound weld. 

HDPE pipe welding using the butt fusion method requires a specialised machine that holds and heats the two pipe ends. These are then pressed together under pressure for some time until it cools. 

However, the challenge in using this welding technique is the probability of welding flaws and the reduction of the material’s structural strength. That’s why it’s crucial to conduct a thorough inspection to assess the quality of the weld.

Electrofusion welding is used in conditions where butt fusion is not viable. This happens when there is a need to add valves, elbows, and tees.

HDPE welding using the electrofusion method is performed using a moulded socket fitting that has a built-in electrical resistive heating coil. This coil melts the inside of the prefabricated fitting and the outside of the pipe wall.

When properly made, the resulting homogeneous joint can be as strong as the original pipe.

The last type of poly welding is extrusion. This is performed using a hand tool known as an extrusion welder. Specialists use this tool to join tanks and pipes made from thicker materials.

Extrusion welding heats and melts a plastic filler material while simultaneously heating the base material to prepare it for welding. The plastic filler material is then extruded onto the heated base material.

While this method is common in HDPE welding, it can also be performed on other thermoplastic materials such as polyvinyl chloride (PVC), polypropylene (PP), and polyvinylidene fluoride (PVDF).