These terms get used interchangeably in advertising, which makes it hard to know what you are buying. In practice they describe different levels of the same underlying process: using an abrasive and a machine to level the surface of the clear coat.
Polishing
Polishing is the general term for using a machine and an abrasive liquid to refine paint. A light polish enhances gloss and removes very fine marring. It is the least aggressive machine step and removes the smallest amount of clear coat.
Compounding
Compounding uses a more aggressive abrasive to remove deeper defects: heavier swirls, oxidation, sanding marks. It cuts faster and leaves its own marring behind, which is why it is always followed by a refining polish.
Paint correction
Paint correction is the overall process of removing defects to a defined standard. It might be one polishing stage or three, depending on the paint's condition and the result you want. The word describes the goal rather than a single technique.
Glazing and filling
Glazes and some all-in-one products contain fillers that temporarily hide defects rather than removing them. They can make a car look excellent for a few weeks, after which the fillers wash away and the swirls reappear.
This is worth knowing before buying a used car that looks unusually good on a dealer lot.
Which one do you need?
- Paint looks good but slightly flat: a light polish
- Visible swirls in sunlight: one-stage correction
- Heavy swirls, oxidation, water spot etching: multi-stage correction
- Preparing for a ceramic coating: correction to the level the paint allows
- Deep scratches that catch a fingernail: none of the above, that is paint repair
Frequently asked questions
- Does polishing damage paint?
- Every polishing step removes a microscopic amount of clear coat. Done properly and infrequently, that is not a concern. Done repeatedly and aggressively, it is.
- Can I polish a car myself?
- With a dual action machine and patience, light polishing is achievable. The risk is in aggressive compounding on edges and thin panels, where damage happens fast.
- How do I know if a shop used fillers?
- Fillers wash out over several washes. If defects reappear a month after a correction, that is what happened.