identify plastic & determine repair method
If you can’t find the Plastic ID Symbol...
Identification Process for Bumpers
Identification Process for Plastics in General
Is the plastic extremely rigid?
Note: welder must be very hot to per- form this test effectively.
Is the part very rigid with lots of glass fibers in the broken area?
Probably SMC. Repair using Method E with 2020 SMC Hard- set Epoxy.
Does it bubble, brown or smoke when you try to melt it?
Flexible or Rigid?
Judging from the feel and appearance of the plastic, test weld with one that matches best.
Xenoy (PC/PBT). Repair using Method B with 5003R7 Poly- carbonate Rod.
Is the back- side of the part yellow?
Polyurethane. Repair using Method A with 5003R1 Urethane Rod.
Does it bubble and smoke when you try to melt it?
Probably TPO, TEO, or TPE. Repair using Method C with Uni- Weld FiberFlex.
Probably Poly- urethane. Repair using Method A with 5003R1 Ure- thane Rod. If waxy feeling, may also be Crosslinked Poly- ethylene. Repair using Method C with 5003R4
Thermoset Rigid Plastic, like Metton. Repair using Method E with 2020 SMC Hardset Epoxy or Method G PlastiFix Rigid Plastic Repair System
To perform a test weld, clean and sand a small area on the backside of the part. Make a small spot weld on the surface. After the weld cools, try to pick it off with your fingernail. The one that sticks best is the one to use.
Very Rigid - R7 Rigid - R3, R6 Semi-Rigid - R2, R4, R5 Flexible - R1, R4
Do any of these rods stick well?
Repair with selected welding rod using Method B.
If Rigid, repair with Method G PlastiFix Rigid Plastic Repair System. If Semi-Rigid, probably TPO, TEO, or TPE Repair using Method C with Uni-Weld FiberFlex.
More than 95% of late model bumper covers are made from one of three materials. Here’s the approximate breakdown:
TPO, TEO .........85% PUR...................10% Xenoy ................3% Other .................2%
FiberFlex will be the best way to repair most of today’s bumpers. PUR is used most commonly on higher-end cars. Xenoy is almost gone nowadays.
clean surface and align damage
Clean Surface Before Repair
In order to maximize strength and adhesion of the repair, it is important to thoroughly clean all contaminants from the surface in the damaged area.
Step 1. Clean both sides with soap and water. Dry off with a clean cloth or compressed air.
Step 2. Spray on 1000 Super Clean Plastic Cleaner and wipe off while wet with a clean, lint-free cloth. Wipe in one direction to avoid spreading contaminants back over the clean area.
If the plastic is distorted, heat with 6500VT high temp heat gun and reshape the distorted area. When heating plastic, it is important that the plastic be heated all the way through. Hold the heat gun on the area until the opposite side of the plastic is uncomfortable to the touch. Once heated, force the plastic back into position with a block of wood or other tool, then cool the area with a clean cloth.
Thermoset polyurethanes (PUR, RIM) have a “memory” that will often cause them to go back to their original position if held under a heat lamp or in a heated spray booth.
If the part is cut or torn to the edge, align the outer surface with 6481 aluminum body tape and begin the repair process on the backside. By aligning the outer surface, you minimize the amount of filler required later to restore the proper profile to the part.