Plastics Identification, How to ID Plastics

Plastics Identification:

You can only weld “like” materials. For example, Polypropylene (most car bumers) can only be welded with a Polypropylene welding rod. So it is very important to first identify the material to be welded. Today most plastics used in the manufature of modern vehicles are stamped with plastics identification codes, however, where this identification is not present, a welding test is required to ID the material to be welded. The quickest, safest and easiest way to do this is using a Techspan Rod Test Kit or RTK

Rod Test Kit (RTK) weld test procedure:

  • Simply clean an area on the underside of the part to be tested. Ensure you remove any contamination (grease, oils, paints etc) before attempting his test
  • Select a rod from the Rod Test Kit (RTK) that appears and feels similar to the parent material
  • Attempt to weld (approx. 30mm) of the selected rod to the parent material, leaving a tail (30mm long) at 90 deg to the parent
  • Once complete, allow to cool. It is important to note that plastics will not hold full strength until completely cold
  • Attempt to remove the rod with a pair of pliers, pulling at 90 deg to the welded part. If the rod snaps off leaving the material on the parent, you know you have a match
  • Repeat the test with another rod selection until you find the correct match

For more in depth information covering the Plastic Welding Technique – click here