Plastic parts can be identified
by the SAE the 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 one 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.