Deep Scratch Repair Overview
The first step in repairing a scratch on your car is to identify what type of scratch you are dealing with. The chart below shows the different types of scratches you might encounter on your vehicle.
If you can feel the scratch and it catches your fingernail, or the primer color or bare metal is exposed, you are indeed dealing with a deep scratch that will require primer, basecoat, and clearcoat in order to be fully repaired.
The Repair Process:
1. Surface Preparation - Thoroughly clean the area with soap and water and then dry completely. Use wax and grease remover and a clean microfiber towel to assure the area is free of surface contaminates. For better results do not apply paint in direct sunlight, high humidity, or where silicone waxes and tire dressings are present.
2. Sanding - Sand out rust, scratches, or bad surface damage with 180-320 grit sandpaper. Primer will cover over 180-320 grit sand scratches. Use 600 wet sandpaper to sand the area you will use basecoat. Wet sand the blend panel (area that might get some basecoat and will get clearcoated) with 1000-1500 grit wet sandpaper. Entire area to be painted should be dull and smooth.
For new plastic parts lightly scuff the area with a grey (fine) scuff pad. For new metal parts you may lightly use a red (medium) scuff pad for topcoating with solid colors or grey scuff pad (fine) for metallic and pearls.
3. Masking Off Adjacent Panels - Mask off adjacent panels using automotive grade masking tape and masking paper to prevent overspray. Never tape off mid panel or you will see a tape line. Make a line with tape first, then tape paper to your existing tape line. Doubling up newspaper will work fine but paint has a possibility of bleeding through with excessive heavy coats. Use 1 1/2" or 2" masking tape for small areas like tail lights and reflectors. In the case of painting in an enclosed area mask the entire car with plastic sheeting to prevent overspray.
4. Primer- Shake primer well. Apply aerosol primer spray paint over clean, sanded metal or plastic treaded with adhesion promoter. Primer will fill 180-320 grit sandpaper scratches. Apply 3 or more coats, waiting at least 5-10 minutes in-between each coat. After 30 minutes, the primer can be sanded with 600 grit sandpaper. Use water to clean off sanding dust and dry the area completely. Replace the dust contaminated masking tape and paper. Do not use prep solvent or wax and grease remover over the fresh primer. Instead- use a tack rag to pick up any remaining lint and dust particles.
5. Basecoat Application - Thoroughly shake the basecoat aerosol can before applying. Spray a test panel with base coat and clear coat first to compare color match and coverage. Apply as many medium coats necessary to cover the area, waiting 5-10 minutes between each coat. Each coat should appear uniform and dry between each coat. You may gently use a tack cloth between each dry coat of basecoat. Spray light dust coats if a metallic or pearl color looks too dark. Wait 30 minutes before using clear coat.
Tri-coat paints require a slightly different process. Spray the groundcoat color first, one coat at a time until the area is covered. Then apply the midcoat pearl color one coat at a time until you achieve the pearl effect of the factory color.
6. Clearcoat Application - Shake the aerosol clearcoat can well. Allow 30 minutes after base coat color has been applied to apply the clear coat. Apply 4-5 wet (but not dripping) coats waiting at least 10 minutes in between coats. Each coat should be dry to the touch (not tacky) before moving on to the next. Feel along the tapeline in order to see if the clearcoat has dried instead of touching the panel. Please note that warmer weather will shorten the dry time, and cold weather will extend the dry time. If you fail to allow adequate time for the clearcoat to dry, it may result in a color mismatch, heavy orange peel texture, and/or a lack of gloss.
After one day, you may wet sand out any orange peel or dust embedded in the clearcoat. Start by using 1500 grit wet sandpaper, then apply rubbing compound to restore gloss to the area. Do not wax your vehicle for at least 30 days.