Gambar 2 - Bird Burn
This diagram (gambar 2) shows how the burn from a bird dropping looks on the paint surface. In most cases the burn won't be very deep, but you will see it on the surface of the paint. Polishing helps to level the surrounding paint so the etch mark no longer shows.
Gambar 3 - Swirl Mark
The reason swirl marks and other micro marring show up so prominently on black and other dark colors is because the sides of the marring reflect light. When you polish, the edges are rounded and reduce reflection.This diagram shows what severe micro marring might look like in a cross section of paint.
Gambar 4 - Medium Scratch
This is a medium scratch (Gambar 4). You will be able to feel it with your fingernail, but it does not go through to the primer. The best way to fix this kind of scratch is to round down the edges using a medium-grit rubbing compound, and bring back full gloss with a good polish.
Gambar 5 - Deep Scratch
Deep scratches and chips that go through the color coat into the primer or down to the metal can only be repaired using touch-up paint.
PAINT CHIP & SCRATCH REPAIR
You'd be hard pressed to find a car on the road that does not have paint chips and parking lot scratches. While good detailing practices can't prevent nicks and scratches, repairing them will restore your car's "like new" appearance. In this section, I'll describe the methods I've used for years to repair chips and minor scratches.
Paint Chip & Scratch Reality
Touching up small nicks and scratches is well within the skill level of most do-it-yourself car enthusiasts. Some nicks can be quickly repaired with a small dab of touch-up paint, while others will require more time, effort and skill. It's important to know what you should and shouldn't tackle, based on your knowledge of paint and tools.
By far the easiest colors to repair are black and white. Black and white are very forgiving on shade variations. Conversely, metallic paints (those with metal flakes) can be quite difficult to match perfectly.
Before you get started repairing nicks and scratches, you should know what to expect. Small nicks are easy to repair by filling the nick with paint, leveling the filled area, and buffing the repair area to blend and restore luster. Repairing small scratches, as from a key or shopping cart, is similar, but more time consuming. Fixing a ding (a small dent which may or may not have taken a nick out of the paint) is not usually possible for the do-it-yourselfer.
Here are some other things you should know:
- If you know your car's factory paint code, you can purchase an exact color match touch-up paint from your local dealer. If you don't know the factory paint code, look in your owner's manual for the location of the code, or ask your dealer. If you have a late model car, chances are you will find a color match at your local auto parts store.
- Use a small artist's paintbrush (#2 is ideal) or a round wooden toothpick to apply the touch-up paint, not the fat brush included with the bottle of touch-up paint.
- Always test the touch-up paint for color matching in an inconspicuous area.The area to be repaired must be perfectly clean and free of wax, rust and oils.
- Don't attempt a touch-up if the temperature is below 60 degrees (Fahrenheit).
Here's what you need to properly repair nicks and scratches:
- Color-matched touch-up paint (Try Paint Scratch.)
- Automotive or metal primer (only required if you have exposed metal)
- Dawn dish-washing liquid
- Prep solvent (Prepsol) or denatured alcohol
- Foam swabs (from electronics supply) or pop swabs containing alcohol
- Sanding block and 1500- or 2000-grit wet and dry sand paper (A rectangular rubber school eraser makes a good sanding block for small touchups.)
- Fine cut rubbing compound
- Artist's paintbrush (#2) and round toothpicks (plastic)
- Cotton terry cloth towels
- New pencils with unused erasers
- Rubber cement
- Plastic cups
- Blue masking tape (easy-release type)
- Large-diameter paper hole punch (hand type)
Paint Chip Preparation Process
Before applying paint, you must prepare the chip to accept paint. Although paint may adhere for a while to a chip with rust, dirt or oil, eventually the repair will fail. The preparation process begins the day before you repair the paint chips and scratches.
The afternoon before starting your chip repairs, wash your car with Dawn dish-washing detergent to remove all wax and silicone from your paint. Dry your car thoroughly and put it away for the night.
After washing your car, make up several sanding pencils. Use a hole punch to punch out a few dots from the 1200-grit wet and dry sandpaper. Apply the sandpaper dots to the ends of your pencil erasers with rubber cement. Allow them to dry overnight. You will use the sanding pencils to scuff up and clean out nicks.
To make a chip ready for touch-up paint, you must make sure it does not have loose edges, and then clean it and sand it. I use a toothpick to check the edges of a chip. If the edges are loose or lifted, I use the toothpick to knock off the loose paint. To clean, I like to use denatured alcohol or Prepsol and a foam swab. I pour a little bit into a plastic cup and use a foam swab to clean the chip and surrounding area.
Next, I use a sanding pencil to clean out the chip and rough up the edges. Simply dip the sanding pencil into a cup of clean water, dab a few drops of water on the chip, and gently rotate the sanding pencil over the chip. Keep the area you sand as small as possible. Rotating the sanding pencil back and forth in your fingers 8 to 10 times should be enough to do the job. If the chip has exposed bare metal, or if you can see rust forming, use the edge of the pencil eraser to remove the rust. When you finish sanding the chip, dry it with a terry cloth towel, and clean it again with Prepsol and a foam swab.
How-to Apply Touch-up Paint
Once the damaged areas are cleaned and prepared, you can begin the touch-up itself. If a chip exposed bare metal, you must primer the chip before the color touch-up. After mixing thoroughly, pour or spray a small amount of your primer into a plastic cup. Next, use a clean toothpick to apply the primer. I do this by dipping just the tip (2 to 3 mm) of the toothpick into the primer. If I get a blob, I wipe it back.
Next, I touch the tip of the toothpick to the center of the chip and allow the paint to flow off of the toothpick into the chip. You will be amazed how well the capillary action works. If you prefer, you can use the #2 artist's brush. Do not allow the primer to overflow the sides of the chip. Allow the primer to dry for 2 or -3 hours. You can speed dry the primer with a hair dryer after allowing it to air dry for one hour. Simply wave the hair dryer 3 to 4 inches over the primered chip for 30 to 40 seconds. Do not touch the chips with your hands, as the oils from your skin will prevent the color coat from adhering.
Now, mix your color-matched paint thoroughly, and pour a small amount into a clean plastic cup. As with the primer, use a clean toothpick or #2 artist's brush to apply the color coat. Touch the toothpick or brush to the center of the chip, and allow capillary action to pull the paint into the chip. Apply a small dab at a time, and allow it to dry for 2 to 3 hours. You must repeat this process several times, so don't try to fill the chip in one pass. Applying several thin layers will produce much better results.
The color touch-up process is complete when you have applied enough coats to slightly overfill the chip onto the roughed-up area surrounding the chip. Once you've filled the chip, allow it to dry for another 24 to 48 hours; the longer, the better.
I'm often asked if it's necessary to apply a clearcoat over chip repairs. I don't think it's necessary or adds any noticeable difference. If you get the proper touch-up paint from your dealer, it will match without using a clearcoat. However, if you're a purist in pursuit of perfection, substitute a clearcoat for the last 2 or 3 coats.
Gambar 6 - Filled Scratch
Here is a close-up picture of a scratch after it has been repaired with touch-up paint. The touch-up creates a raised surface. In order to perfect the repair, the raised touch-up paint must be leveled. I will use 1500-grit sandpaper to level the repair. If you are new to wet sanding, use 2000- or 2500-grit paper.
Level & Polish The Paint Repair
Until you level or mill the paint repair down to the same plane as the original paint, all you'll have is an ugly looking blob. Leveling the paint repair is easily done using a small sanding block and 1500- to 2000-girt wet and dry sand paper. I like to use a 1" by 2" rubber erasure as my sanding block, which helps level touch-up repairs with surgical precision. Don't forget to soak your sand paper overnight (30 minutes at a minimum) before use, as the directions indicate.
To level your paint chips, use your finger to put a small dab of car shampoo on the chip repair for lubrication. Next, use your sanding block and sandpaper to mill the high spot off of the chip repair. I always sand in a straight line, with the length of the car, never in a circle. Keep the area you're sanding well lubricated with water. Wet sanding will dull the paint. Don't worry, your polish will easily restore the finish. When the surface looks level, dry it with a clean towel and inspect with your fingertips. If you can feel a high spot, it needs more work.
Gambar 7 - Leveled Repair
This picture shows the repair area after a couple of passes with 1500-grit wet and dry sand paper. The scratch touch-up is almost level, and you can clearly see the surface scratches (micro marring) I put in the paint surface.
The final step is to buff out the repair with a good polish. If I'm working with my rotary buffer or Porter Cable 7424, I like to use Sonus Restore (SFX-1) followed by Sonus Enhance (SFX-2). Apply the compound and polish to a clean foam applicator pad or polishing cloth, rub into the paint area using a short back-and-forth motion (not in circles), and then buff out with a clean terry cloth towel. Tada! The blemish is gone. The job is much faster if you use a machine polisher.
Gambar 8 - Polishing
The next step is to compound and polish. I did fewer than 20 passes (strokes) with rubbing compound. It does not take much to remove surface scratches. To completely polish and restore the surface, I polished the area twice.
Gambar 9 - After Polish
As you can see, the repair and paint finish turned out to be quite beautiful. There are no visible surface marks in the paint, and the touch-up cannot be detected.
source : http://guidetodetailing.com/damage-repair/paint-repair-clinic/