Paint - Clearcoat Degradation, Chalking and Whitening
Group Ref.: BodyBulletin No.: 331708
Date: November, 1993
SUBJECT:
CLEARCOAT DEGRADATION - CHALKING AND WHITENING
MODELS:
PASSENGER CARS WITH BASECOAT/CLEARCOAT
CONDITION:
The vehicle exterior surface may show large chalky or white patches in the clearcoat, usually but not limited to the horizontal surfaces.
Blacks, Dark Blues, Reds, may have potential for this condition. On rare occasions, other colors may be involved.
CAUSE:
The clearcoat (with sunlight and heat) may degrade and turn white or chalky.
IDENTIFICATION:
On a clean surface, at or above room temperature, firmly apply a 2" wide piece of masking tape to the chalky or white area of the clearcoat and pull upward quickly. The adhesive side of the tape WILL NOT HAVE THE PAINT COLOR ON IT. A light shine or reduced tackiness may be noticed on the tape adhesive surface, indicating clearcoat transfer to the tape.
CORRECTION:
Refinish all horizontal surfaces using the following procedure.
- Remove the clearcoat layer from all horizontal surfaces and the top surfaces of fenders and quarter panels.
NOTE:
In some cases, it will be necessary to remove the clearcoat from the upper vertical surfaces of fenders, doors and quarters (approximately 3"), and the top areas directly above the front and rear wheelhouse openings.
- Lightly sand any previously exposed base color to remove any chalky residue from the surface.
- The vertical surfaces should be sanded and colorcoated to the next lower breakline (typically the body side moldings) for color uniformity of the repair.
IMPORTANT:
The following procedure covers clearcoat degradation only. It does not address any other paint condition.
PROCEDURE:
1. Some vehicle components will be removed, while others will require masking. The list located at the end of this bulletin will establish the removal items. Items not found on the list and non repair areas are to be masked.
2. Prior to removing the paint finish, clean the area to be refinished with soap and water, followed by an appropriate wax and grease remover.
3. Mask the remaining moldings and hardware for protection during sanding.
4. Remove the clearcoat material from all horizontal surfaces (and tops of fenders and quarters) using a DA (dual action orbital sander) and # 120 grit sanding discs. Lightly sand any previously exposed base color to remove any chalky residue from the surface.
NOTE:
Chemical stripping is not recommended because of negative Impact to moldings, non-metal components, ELPO and environmental concerns.
5. Lightly sand the unaffected vertical panels to the next lower breakline, smooth and "featheredge" the surface to be refinished with # 240 or # 320 grit sandpaper for maximum adhesion.
6. Blow off the sanding dust and residue.
7. Remove masking tape and remask all necessary areas for priming.
8. Wipe and clean repair area with an appropriate wax and grease remover.
9. Wipe repair area with a tack rag.
10. Apply a coat of self etching or epoxy primer to the bare metal areas exposed during the sanding process. Follow manufacturer's instructions and recommended dry times.
Typical materials would be: DuPont 615S/616S, BASF DE17/PR80/DA18, PPG DP40/DP401 or equivalent.
V.O.C. materials would be: DuPont 615S/616S, BASF DE17/PR80/DA18, PPG DCP21/DCP212 or equivalent.
11. Apply two to three medium wet coats of primer surfacer to the entire repair area (including vertical surfaces) of the vehicle, following manufacturer's instructions for application and film build requirements.
NOTE:
A guide coat Is recommended to highlight high and low spots during the wet or dry sanding process.
Typical materials would be: DuPont 1120S/1130S/1125S, BASF DP20/PR80/PH36, PPG K36/DT870/K201 or equivalent.
V.O.C. materials would be: DuPont 275S, BASF HP400, PPG DCP21/DCP212 or equivalent.
12. After adequate drying time, wet sand with # 400 grit (or finer) or dry sand with # 320 grit (or finer) sand paper.
13. Repeat steps 6 through 9 and remask the vehicle.
14. Apply a medium coat of primer sealer to the entire repair area.
Typical materials would be: DuPont 2610S/2605S, BASF DP21/DH60/PR80, PPG DP40/DP401 or equivalent.
V.O.C. materials would be: DuPont 210S, PPG DPW1834 or equivalent.
15. Apply 2 to 3 medium wet coats of basecoat (or until primer is hidden). Follow manufacturer's instructions and recommended dry times.
16. Apply clearcoat. Follow manufacturer's instructions and recommended dry times.
17. After sufficient force dry or air dry time, remove masking.
18. Spot finesse/polish as required.
19. Reinstall previously removed hardware and moldings.
HARDWARE ITEM REMOVAL
Vehicles have many different hardware options and treatments, but the following list of items can be used as guidelines for item removal.
^ Windshield moldings (non-modular type windows)
^ Back window moldings (non-modular type windows)
^ Side view mirrors (outer panel mounted)
^ Ft. door belt seal strips (doors without window frames)
^ Name plates on fenders, doors, quarters, fascias and deck lids
^ Antenna base (power or fixed mast types)
^ Wiper arms (on vehicles with cowl grilles)
^ Cowl vent grille
^ Fender marker lamps
^ Tail lamps
^ Rocker aero molding emblems
^ Roof weld seam moldings
^ Auxiliary weatherstrips
^ Deck lid lock cyl. cover
^ Wheel opening moldings
^ Roof drip scalp moldings
^ Door edge guards*
^ Spoilers*
^ Luggage racks*
^ Hood grills/ornaments*
^ Decals*
^ Stripes*
^ Body side moldings if mechanically retained. If adhesive retained, mask molding.
NOTE:
Only items marked with an asterisk are "add" conditions to the Major Operation being performed. Removal time for the other Items listed is included in the allowance.
LABOR OPERATION: A6110
TIME ALLOWANCE: See Chart That Follows (**)
NOTE:
The time allowances provided on the chart includes the hardware removal and installation (as indicated by the list guidelines), the masking and unmasking of the vehicle, clearcoat removal (as indicated by the guidelines), the refinish (and colorcoat when required), mix time for primer/paint and clearcoat, finesse/polish where required, washing and preparing the vehicle for delivery.