PP, ABS or PE: how to tell what the part is made of

The welding rod must be the same plastic as the part. Otherwise the materials will not bond: the seam looks solid but peels off at the first impact or frost. So identify the material before buying a rod.

Where to find the marking

The maker stamps the material code into the part itself — raised letters in angle brackets. Look:

• On the back of the part — most often right there.
• On bumpers — near the mounts and along the edge, closer to the corners.
• On tanks and canisters — on the bottom or on the side near the neck.

What the codes mean

• >PP<, >PP+EPDM< — polypropylene. Bumpers, washer tanks, wheel arch liners, guards.
• >TPO<, >TEO< — polypropylene with rubber. Modern bumpers, softer to the touch.
• >ABS< — acrylonitrile butadiene styrene. Housings, body kits, dashboards, grilles.
• >PE<, >HDPE<, >PE-HD< — polyethylene. Canisters, tanks, kayaks, garden equipment.
• >PVC< — polyvinyl chloride. Pipes, profiles, rigid covers.
• >PPR< — polypropylene random copolymer. Heating and water pipes.

If there is no marking, or a different one

Markings >PA< (polyamide), >PC< (polycarbonate) and >PUR< need a different approach — an ordinary rod will not weld them. If the marking has worn off or you cannot find it, send a photo of the part on Telegram: the shape, colour and break usually reveal the material.

A quick test on the spot

Shavings of polypropylene and polyethylene float in water; ABS and PVC sink. It does not replace the marking, but it rules out half the options when no stamp is visible.

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