Below are replacement plastic welding rods for all Urethane Supply plastic welders. These rods will also work for any hot-air or hot-tip plastic welder.
There's nothing special about plastic welding rods. They melt at the same temperature as the part you're fixing and when cooled, have identical properties as the repaired part. Just think of the rods as a filler material (like metal welding). Your objective is to fill the crack or split. It's quite easy.
As a general rule, you can estimate 1' of rod per 8" of welding.
Since you must match the rod-type to the material (ABS, PCV, or Nylon, etc.) you can do so by looking for the international stamp somewhere on piece to be repaired (it looks very much like the 'recycle' symbol you see bottles, with three arrows going in a triangle). By international standards, every separate piece of plastic must have that stamp to indicate its plastic type (ABS, TPO, Polyethelene, etc.). For example, on an ATV you find the 'type' stamp on each fender piece, radiator cover panel, bumper and headlamp cover. Stamps are always located on the underside for cosmetic reasons.