How to Identify Thermoplastics prior to Welding

Plastics Identification – How to ID thermoplastics:

As you can only weld “like” materials – for example, Polypropylene can only be welded with a Polypropylene welding rod – it is very important to first identify the material to be welded. Today most plastics used in the manufacture 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) – test procedure:

  1. Simply clean an area on the part to be ID tested. Ensure you remove ALL contamination (grease, oils, paints etc) before attempting his test
  2. Select a rod from the “Rod Test Kit” that appears and feels similar to the parent material
  3. Attempt to weld approx. 30mm of the selected rod to the parent material, leaving a tail sticking up at 90 deg to the parent
  4. Once complete, allow the plastic to cool. It is important to note that plastics will not hold full strength until completely cold
  5. 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
  6. 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