POLISHING AND SWIRL MARK REMOVAL TECHNIQUES

SUBJECT: INFORMATION ON POLISHING AND SWIRL MARK REMOVAL TECHNIQUES FOR BASECOAT/CLEARCOAT PAINT

MODELS: 1993-96 PASSENGER CARS AND TRUCKS WITH BASECOAT/CLEARCOAT

THIS BULLETIN SUPERSEDES AND CANCELS BULLETIN #111702. PREVIOUS DIVISIONAL PUBLICATION NUMBERS WERE:

BUICK 93-10-22 CADILLAC T-93-104 CHEVROLET 93-188-OB GM CANADA 93-10-158 OLDSMOBILE 07-93-106 (SERVICE GUILD) PONTIAC 93-10-28

TODAY'S BASECOAT/CLEARCOAT PAINT FINISHES ARE VERY DIFFERENT FROM MATERIALS USED ON VEHICLES IN THE 1980'S.

MATERIALS, PROCEDURES AND EQUIPMENT WHICH ONCE WORKED WELL FOR POLISHING TRADITIONAL FINISHES MAY NOT BE ACCEPTABLE FOR USE ON BASECOAT/CLEARCOAT PAINT SURFACES. THE USE OF OUTDATED MATERIALS, PROCEDURES AND EQUIPMENT MAY PRODUCE WHAT APPEARS TO BE ACCEPTABLE RESULTS UNDER SHOP LIGHTING, BUT WILL BE UNACCEPTABLE TO THE OWNER WHEN THE FINISH IS EXPOSED TO SUNLIGHT (TYPICALLY, SWIRL MARKS).

WHILE THE FOLLOWING INFORMATION CAN BE MOST HELPFUL IN THE NEW CAR "PREP" AREA, IT SHOULD ALSO BE MADE AVAILABLE TO THE "USED CAR" AREA AND THE COLLISION/PAINT REPAIR AREA.

KEEP THE VEHICLE CLEAN AND DRY:

- AVOID WASHING VEHICLES IN DIRECT SUNLIGHT.

- AVOID USING STRONG SOAPS OR CHEMICAL DETERGENTS.

- USE "BRUSHLESS" TYPE AUTOMATIC CAR WASH EQUIPMENT.

- AVOID USING PRODUCTS CONTAINING ACIDS (UNLESS SPECIFIED TO CORRECT A CONDITION SUCH AS "RAIL DUST").

- DON'T USE BRUSHES OR BROOMS TO REMOVE SNOW OR ICE FROM VEHICLES IN STORAGE OR ON LOTS.

- CLEANING AGENTS AND WATER SHOULD BE DRIED PROMPTLY AND NOT ALLOWED TO DRY ON THE SURFACE.

- STANDING RINSE WATER SHOULD BE DRIED PROMPTLY AND NOT ALLOWED TO DRY ON THE SURFACE.

- DRYING WITH A SOFT CHAMOIS IS RECOMMENDED.

DON'T CREATE A PROBLEM:

- DO NOT POLISH VEHICLES UNLESS A SURFACE CONDITION EXISTS THAT CAN ONLY BE CORRECTED BY POLISHING (SEE ATTACHED CHART).

- IF A SURFACE CONDITION DOES EXIST, THE REPAIR APPROACH SHOULD BE ONE OF "LESS IS BEST" (THE VERY LEAST IT TAKES TO CORRECT THE CONDITION).

- AVOID REMOVING TOO MUCH CLEARCOAT (WHENEVER POSSIBLE, USE PAINT GAGES BEFORE, DURING, AND AFTER POLISHING).

- USE ONLY THE PRODUCTS RECOMMENDED IN THIS BULLETIN (OR THEIR EQUIVALENT).

- MAKE SURE THAT ANY POWER POLISHING EQUIPMENT DOES NOT EXCEED THE REQUIREMENTS IN THE POLISH MANUFACTURER'S RECOMMENDATION OR IN THE ATTACHED CHART.

FINAL STEP:

THE FINAL STEP OF THE FINESSE/POLISH PROCEDURE IS THE REMOVAL OF SWIRL MARKS. SWIRL MARKS ARE DEFINED AS VERY FINE SCRATCHES IN A UNIFORM CIRCULAR DIRECTION THAT CAUSE AN OPTICAL DISTORTION ON THE PAINT SURFACE. SWIRL MARKS MAY NOT BE VISIBLE WITH SHOP LIGHTING. THEY SHOULD BE VIEWED IN DIRECT SUNLIGHT OR UNDER SPECIFIC LIGHTS, I.E. SODIUM VAPOR (PARKING LOT TYPE LIGHTS).

SWIRL MARK REMOVAL - TO REMOVE SWIRL MARKS, USE AN ORBITAL POLISHER (DA) WITH SPEEDS IN THE 1,500 TO 2,000 RPM RANGE. APPLY A SMALL AMOUNT OF THE APPROPRIATE MATERIAL (SEE CHART) TO THE SWIRL MARK AREA. USE THE PAD ON THE RANDOM ORBITAL BUFFER TO SPREAD THE MATERIAL EVENLY OVER POLISHED AREA BEFORE BUFFING. WHEN BUFFING, KEEP PAD FLAT AND CONSTANTLY MOVING OVER THE REPAIR AREA. POLISH WITH HEAVIER PRESSURE APPLIED FOR 4-6 SECONDS, THEN POLISH WITH LIGHTER PRESSURE FOR 6-8 MORE SECONDS. ALWAYS BLEND OR FEATHER OUTER EDGES OF REPAIR SPOT. AFTER BUFFING, THE BUFFED AREAS SHOULD BE INSPECTED BY THE BUFFING PERSON TO ENSURE THAT THE SWIRLS ARE COMPLETELY REMOVED. IF SWIRLS ARE STILL PRESENT, REBUFF AS NEEDED. HAND WIPE THE SURFACE WITH A CLEAN SOFT, NON-SCRATCHING CLOTH AND A 50/50 MIXTURE OF ISOPROPYL ALCOHOL AND WATER.

- DON'T USE WAX OR SILICONE-TYPE PRODUCTS TO HIDE SWIRL MARKS (THIS CONDITION WILL REAPPEAR LATER AND CAUSE OWNER DISSATISFACTION).

- SPECIFIC CONDITIONS ON PAINT (ENVIRONMENTAL DAMAGE, RAIL DUST, ETC.) CAN BE CORRECTED BY REFERRING TO PREVIOUSLY PUBLISHED SERVICE BULLETINS ON THOSE SPECIFIC TOPICS.

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GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

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