If a person is looking to weld thick plastic parts, then extrusion welders offer a decent solution. Considerable welds greater than 1/2 inch (12.5 mm) are possible with extrusion welders and weld quality is acceptable if the person takes the right steps before, during, and after the welding process.

Like hot air units, the extrusion welder blows hot air to preheat the parent plastic material. A screw (auger) pulls welding rod into the barrel that is heated by radiant heat. The melted rod extrudes through the tip. A PTFE (Teflon) welding shoe attached to the tip gives the welding rod its shape.

Benefits: Large extrusion welders can weld plastics greater than ½ inch (12.5mm) with a single pass.

Drawbacks: Although extrusion welders are useful in high volume welding situations, they have limitations that hamper their usefulness. First, extrusion welders are heavy and difficult to maneuver. Large welders are rarely practical in narrow or hard to reach areas. Even the hand held units may put considerable strain on a person's wrist. Second, extrusion welders (like hot air welders) lay down a weld bead that stays on top of the parent material, therefore the person must scrape away the oxidation layers before welding. Clean-up after welding is important with Extrusion welders that have a Teflon shoe, as any hardened material in the shoe on the next start-up might damage the welder.