Paint correction is a term used to describe the process of removing all exterior defects from a cars exterior painted surfaces, where safely possible. These may be light/medium washing swirls, light/medium/deep scratches.
For this I use a selection of variable speed rotary polishers, a dual action polisher in some instances, and a selection of cutting compounds (machine polishes). However it is not always possible to polish deeper scratches that have gone down to the paints first layer (primer layer) or down to the metal surface. Equally it may not be possible to polish medium to heavy scratches, if the clear coat/lacquered finish will become too thin.
Before commencing paint correction measurements of the vehicle’s paint thickness are taken using an electronic calibrated device. The depths are noted on a car plan diagram in microns (µ). This process provides information as to whether the vehicle has been previously polished, has had post damage paintwork since leaving the factory, or has had areas of filler.
Car paint depth (thickness) can vary between manufacturers’ and, can even be different if the exact same model has been manufactured in a different country. Generally paint depths should be between 100 and 200 µ. Whilst most vehicles have a three coat finish (primer, colour, lacquer or clear coat), some vehicles have a two coat finish (primer & colour) or high gloss finish. Many cars now have a very high gloss finish to some exterior trim, sometimes described as piano black. All of these surfaces can be depth measured if the base material is metal, eg aluminium, steel or galvanised steel, however plastics cannot be measured, eg bumpers.
For machine polishing different grades of cutting compound are used. For a high gloss enhanced finish to brand new paintwork, a single stage polish may only be required. For damaged black paintwork, a 3 or even 4 stage polish may be needed.
I only use 3M, Koch Chemie and CarPro machine polishes, depending on the level of cut required and the desired finish.
If full paint correction is not required, or can't be safely achieved. A less aggressive enhancement machine polish may be carried out to increase gloss and remove washing swirls.