Swirl Marks Explained
Swirl Marks - what are they, what causes them and what can you do with them?
Swirls are superficial surface defects in the paints lacquer (or clear coat), typically caused from improper wash or drying techniques.
Improper washing techniques can be defined as not using safe wash methods. Safe wash methods such as the 2 bucket method with a microfiber wash mitt will ensure dust and dirt is pulled away from the paintwork and rinsed into a bucket of fresh water, eliminating the risk of scratching the paints surface with trailing debris on the next pass with the shampoo and mitt.
Your typical jumbo sponge will allow dirt to sit between the panel and itself allowing it to be rubbed against the paints surface. This coupled with a single bucket where the sponge is then rinsed into, will mean the sponge is likely to pick the dirt (however minuscule) that you just removed and scratch it around the paintwork.
Nylon brushes used by a car wash also inflict damage of a similar nature, sometimes in straight lines (called wash marring) instead of the circular 'spider webbing' associated with swirl marks. The density and strength of the nylon strands are often harder than the paints surface, allowing defects to he engraved into the lacquer, this with added dirt from a dirty wash bucket (which is typical in a car wash environment due to the volume of vehicles that get 'cleaned' with little time in between to maintain buckets) will inevitably cause some form of paintwork damage. This is also the case with the automated car washing systems often available at petrol stations.
Drying with a chamois leather as they're actually abrasive, or wiping a dusty car without any form of lubrication (detailing spray or similar) will also result in this kind of light paintwork defect.
Swirls can typically be removed with machine polishing, the amount of polishing stages required to achieve an improvement or as near as perfect as possible will all depend on client requirements and budget, paint thickness levels and severity of the defects. Machine polishing will 'sand down' the lacquers surface to remove the sharp corners of the scratches to offer a visual improvement, or removed entirely where possible. This form of mechanical abrasion is permanent, and cannot be reversed.
Us as detailers will assess how much lacquer we would be comfortable with removing, just because a scratch can be removed almost entirely, doesn't mean it should due to factors such as paintwork preservation. Lacquer has UV inhibitors that could become inefficient when the thickness of lacquer is reduced, resulting in the colour coat (the coloured layer of the paint) fading underneath the lacquer, resulting in needing a paintwork respray.
Going in blind without paintwork thickness readings, with overly aggressive polishing techniques and compounds is often the workmanship of the inexperienced and the untrained, typically found on the Facebook marketplace or the likes offering ridiculously cheap detailing services. You simply cannot remove scratches safely whilst preserving the paintwork for the low prices and quick timescales they're offering.
Swirls can also be temporarily masked with the use of a glaze, or a glaze based polish. Often 'glazing' swirls is a budget method of rectification as its a lot quicker to achieve. Think of this as filling the scratches temporarily, rather than removing permanently and they will inevitably become visible within a few months.
To prevent or lower the risk of swirls on a new vehicle, or a freshly detailed vehicle would be the installation of a ceramic coating. Once installed the coating will become ultra hard and help prevent wash marring, although not a substitute for using incorrect wash techniques. (More info on this to follow).