Repair Procedure For Moderate Acid Rain Damage
COLOR SANDING & BUFFING
Materials and supplies necessary for this procedure:
^ # 1500 or # 2000 grit wet-dry sandpaper which has been pre-soaked in clean water.
^ Soft foam rubber hand-sanding pad
- 3M P/N 05530; Meguiar's P/N E7200 or equivalent.
^ Liquid automotive washing soap, water pail, hand-held spray pump bottle.
^ Variable speed rotary buffer, speed range 1200 - 1800 rpm (dual-action buffers may not adequately remove sanding scratches).
^ Buffing system of choice (refer to materials listed under repair of Minor damage).
REPAIR STEPS:
1. Move vehicle out of direct sunlight and allow paint surfaces to cool if necessary. Dark painted colors become warmer in direct sunlight and require a longer period to cool off.
2. With vehicle surfaces cool, wash with soap and water and then neutralize any remaining acid with a baking soda and water solution (one tablespoon baking soda to one quart of water), followed with a thorough fresh water rinse.
3. Mix liquid automotive washing soap in a pail of clean water (follow manufacturers mixing instructions) and immerse recommended wet-dry sandpaper. Allow sandpaper to soak for several minutes.
4. Using a # 1500 or # 2000 grit wet-dry sandpaper with a soft foam rubber sanding pad, carefully color sand affected paint areas. To maintain the cleanest possible working surface and prevent clogging of paper, frequently apply clean water from a hand-held spray pump bottle. During this process, wipe down sanded areas often to determine if spots have been removed.
Note: When performing this procedure, be sure to measure paint film thickness before, during (continuously) and after sanding with a Film Thickness to prevent excess paint removal. Film thickness gauges like the ELCOMETER 211 (magnetic) or equivalent, ELCOMETER 300 or Fischer Deltascope MP2 (both digital) or equivalent, are ideal instruments to monitor paint film thickness during the color sanding operation. Consult your local paint or tool jobber for pricing and availability. In all color sanding situations, remove no more than a total of 1/2 mil on clear coats, or 1 mil on solid colors. Also, be certain to always sand in one direction and never in a circular pattern.
5. After affected areas have been sanded, install one of the recommended buffing pads and set buffer speed in the range of 1200 - 1800 rpm for a Meguiar's foam pad; 1500 - 1800 rpm for 3M's wool pads.
Note:
^ When Meguiar's # 2 Hi-Tech Cleaner is used, the # 9 Hi-Tech Swirl Remover should also be used to produce a final finish.
^ If Meguiar's more aggressive # 1 Machine Cleaner is used, the # 3 Machine Glaze should be used to produce a final finish.
^ Regardless of manufacturer, never use different buffing/polishing compounds on the same pad.
6. Based on manufacturer guidelines, apply recommended buffing/polishing material sparingly to about a 2 sq.ft. section of the affected panel and wipe buffer pad once across the area. Begin and continue buffing area until haze of material is almost gone.
CAUTION: Use only light pressure on the buffer to prevent burn-through damage to the paint surface.
7. Carefully inspect the buffed paint area for remaining acid spots. If any are found, further sanding and polishing is necessary.
8. Continue to buff surface and if necessary, re-sand the remaining affected areas. Be sure to continuously measure the paint film thickness during sanding to prevent excess film removal. As stated previously, remove no more than 1/2 mil on clear coats, 1 mil on solid colors.
9. Following completion of color sanding procedure, carry out final buffing/polishing procedure to achieve a hi-gloss finish.