Plastic parts can be identified by the SAE code, which is usually found on the
rear of the part, and/or by the characteristics of the plastic. Knowing the type of
plastic aids in selecting the proper repair materials and in selecting the proper
repair procedure.
Look for the SAE code stamped into the part.
Code Found
- Match the code to those in the plastic identification chart to determine
whether the plastic is thermoplastic or thermoset plastic, and whether the plastic
is rigid or flexible. Refer to
Plastic Identification and Refinishing Systems
.
- Identify any special handling procedures. Refer to
Handling Precautions For Plastic
.
No Code Found
Caution: Do NOT use a plastic burn test to distinguish the type of plastic. The
burn test produces vapors which are harmful.
Perform 1 or both of the following tests to determine if the part is thermoplastic
polyolefin or thermoset non-polyolefin.
Float Test
- Cut a shaving of plastic from the back of the part.
The shaving
should be free of mold release agents and paint.
- Place the shaving in a container of water.
• | Thermoplastic polyolefin floats |
• | Thermoset non-polyolefin sinks |
Abrasion Test
• | Sand a spot near the damaged with Grade 36 Roloc Disc. |
• | Thermoplastic polyolefin material melts or frays when sanded. |
• | Thermoset non-polyolefin material sands cleanly. |
Thermoplastic and thermoset plastics can be either rigid or flexible. Thermoplastic
plastic parts are best repaired with a hot iron plastic material-feed welder, but
are usually replaced. Thermoset plastic can be repaired with epoxy or other more rigid
2 package repair material.