One of the trained skills of a professional detailer is compounding and polishing your vehicles paint to remove imperfections such as etching from acid rain or bird bombs, micro-marring from improper wash technique, and oxidation. Proper correction of these blemishes is to remove microns of the paint surface or clearcoat to 'level' the paint surface.Most vehicles have a paint thickness reading of 4.0-4.5 mils (thousands of an inch) and even severe correction with wetsanding will only remove about 0.3 mils. Is it possible to "polish the paint off your car"? Not likely, as a typical detail will remove less than 0.05 mil of clearcoat. However, frequent severe paint correction could greatly diminish the finish which is why proper paint care is important in the first place. So what happens if the scratch is already through the paint and primer?
A typical rule of thumb is if you can feel the scratch with your finger nail then it is beyond repair from the scope of simple polishing. Scratches into the primer are common and should be touched up with paint to prevent rusting. If the scratch is through the paint and primer into the metal, then it should be touched up immediately. Paint pens and touchup paint bottles can be found at the local automotive parts store or online (I recommend Paint Scratch). Often people just use touchup paint to gob it onto the paint surface and leave it as is, creating a spot even more unsightly than the original scratch. I will show you how I correct these deep scratches to remove them completely from sight.
How To Fix Deep Scratches
This is a scratch repair from a recent detail that was far too deep to be corrected from polishing. I did the repair before the actual detail and documented it here for demonstration. The blue masking tape is only for the purpose of making the area more visible. I also adjusted my lighting frequently while working on the repair so the image levels were adjusted for better continuity. The camera position and focus were not changed throughout the repair.
The basics of this sort of scratch repair is to apply the paint. Let it dry and fill the scratch, then level the paint surface. Touchup paint comes in both color and clearcoat, however the color is typically the only one needed. As the paint dries it will condense into the scratch, but the excess will remain on the surrounding area. The repair is completed by removing the excess paint by wetsanding the area then buffing the surface to a mirror shine. (See Below)
Here is this process in action:
The scratch is filled with the touchup paint and allowed to dry (about 10 minutes). This is where most people would end the repair, but you can see how obvious the blemish still is.
The sand paper (2000 grit) is presoaked in water to soften and the area of the repair is lightly sprayed with water.
The repair is gently sanded to remove the excess touch up paint. The fresh paint is much softer than the surface, so it comes off fairly easy.
You can easily see the scratch slowly disappearing!
The scratch is no longer visible but now we need to address the sanding marks.
After one pass with the buffer and compound, you can see there is still a little more work to do to remove the sanding marks but the scratch is gone.
No more scratch!!
The tape is removed and the fender polished to a mirror finish and here is how the repair now looks:
The result is many times better than a slopped on gob of paint and there is no chance of further damage from rusting caused from exposure to the environment. This repair can take between 30-45 minutes per scratch.
Here's to a happy owner and a happy BMW!
