Polishing is pretty much a dark art in the world of automotive detailing: if you believe all the talk about it, it can do everything from removing small scratches to making the damage from a major collision go away. In fact, this is often the most intensive repair that can be done to an existing paint, but it won't do the same job as repainting.
What is polishing?
Polishing is a process in which larger scratches are covered by smaller and smaller scratches until they are no longer visible to the naked eye. This will make your car paint look good to a certain extent, but ultimately, uneven paint surfaces and damage from exposure to the elements can make it look dull. This is where polishing comes in.
Buffing uses a polishing compound, but it removes a thin layer of paint from the surface of the body panel while taking away scratches and damaged paint. The result is a smooth, freshly painted surface that restores the car's lustre.
When should my car be polished?
If polishing and cleaning your car paint doesn't restore its luster, it's time to polish. However, polishing is not a one-step process: once the paint is flat, it still has tiny scratches that need to be sanded away, and then the remaining tiny scratches need to be filled with glaze for the best possible sheen.
Polishing isn't just for old paint either. A new paint job won't have a perfectly smooth surface, so the same care is required to get the finish desired by the new paint.
Polishing Type
Hand Polishing - This is just using a mild polish and a rag to remove paint from small areas. This will smooth out the paint surface around minor scratches and make them disappear.
Orbital Polishing - The orbital bumper rotates the foam disk, but the disk also moves in a circular pattern to prevent the pads from staying in one place for too long. It's not as intense as high-speed polishing, so it's usually used by professionals to get the job done.
High-Speed Polishing - Larger pads and higher speeds allow high-speed buffers to remove large amounts of paint at once. This can quickly remove major damage, but it can easily damage the paint. While hobbyists may try hand polishing or even orbital polishing, high-speed polishing should always be left to professionals.
Polishing isn't just how it's applied. With a range of polishing pads and polishing compounds designed for specific jobs from heavy oxidation removal to finishing, experts need to know which combination will provide the best results.
When is not enough polishing?
The results of polishing can be dramatic, but it's not a panacea. There is only so much paint that can be removed: If too much paint needs to be removed, or if not enough paint can survive the process, the surface needs to be repainted.
If the paint is heavily oxidized, it will appear chalky. At this point, the paint may be too far from the polish.
Very deep scratches can penetrate the paint all the way to the primer or metal. Smoothing the surface removes so much paint that the body panels are exposed to the elements.
For the past 25 years or so, cars have been painted using the varnish process. This will apply a thick clear coat over the colored primer. If this layer is damaged, it may flake off, exposing the base coat. The only way to restore the finish is with a new paint job.