Extruder welders are the right tool when wall sections get thick. Above about 6-8 mm of material thickness, hand-held hot-air welding becomes slow and the bead quality suffers. An extruder welder melts plastic welding rod inside a heated screw barrel, then extrudes the molten plastic directly into a pre-heated joint — producing a fully homogeneous, high-strength weld in a single pass.

This is the technique used to weld:

Polypropylene chemical-resistant tanks and bunds (food-grade and chemical-handling fabrications).
HDPE water tanks, pipework joints and large-bore HDPE fittings.
Polyethylene pond and landfill liners at wall sections beyond hot-air range.
Plastic-fabricated ducting, scrubbers and industrial process equipment.

The Plastic Welding Tools extruder welder range covers small-output micro extruders (around 0.5 kg/hr for tight access and small repairs) through to high-output BAK and Techspan industrial extruders (up to 4-5 kg/hr for production fabrication). Most run on 230 V single-phase Australian power; the higher-output machines require 400 V three-phase.

Extruder welders are typically heavier and noisier than hand-held hot-air tools, and they take a few minutes to come up to temperature, so they earn their keep on long seams and thick sections rather than spot repairs. Heating elements, drive screws and feed rollers are supported in Australia. To understand when an extruder welder is the right tool, see our guide on welding large-section plastics.