There are two types of vehicle paintwork, clear coated and single stage. Clear coated has a clear lacquer that protects the paintwork underneath. Single stage paintwork has no protective lacquer layer and so the paintwork is open to abuse from the elements. If a car has single stage paint and is not cared for properly it can begin to fade and oxidize. UV rays from the sun affect the pigment in the paint and it can begin to fade. Rainwater and surface contaminants can attack the surface causing it to oxidize. This is especially common with red single stage paintwork.
If a single stage paintwork has faded and oxidized considerably it’s quite common to be told that the vehicle would require a full re spray in order to fix it, however this is untrue and the paintwork can successfully be fully restored with the use of abrasive polishes. On rare occasions clear coated paintwork can also fade but as the paint is under the lacquer it cannot be restored by polishing as so would unfortunately require a repaint. The first step to restoring oxidized single stage paintwork is to thoroughly wash and clay the car to remove both loose and bonded surface contaminants ensuring the surface is as clean as possible before polishing.
The severity of the oxidation will determine what kind of polish product should be used. If the vehicle is not too heavily oxidized then an all in one polish product should be able to successfully cut through the oxidation with its light abrasives and restore the paintwork to a high standard. If the paintwork is more heavily oxidized you will need to use a designated abrasive polish product. You should begin using the least abrasive polish only stepping up to a more aggressive product if necessary.
Ideally a dual action polishing machine should be used for restoring oxidized paintwork as it will effectively help to cut through the oxidation and break down the abrasives in the polish, it will also save a little time and require much less effort than polishing by hand. If the paint cannot be polished with a machine though, you can successfully restore oxidized paintwork by hand but it will require a little more effort to ensure that the product is thoroughly worked in and properly broken down. If an abrasive polish is used to remove the oxidation you should ideally re polish the area with a less abrasive product to refine the finish.
Once polished and restored, it is important that the paintwork is properly protected to prevent it from oxidizing again. A good quality synthetic sealant or wax should be used. It is advisable that the chosen product is layered or applied more than once initially to ensure a sufficient level of protection is present, as what you are doing is effectively substituting the lack of clear coat with the protective product. The paintwork should then be regularly maintained by washing it with a good quality waxed based shampoo product, and reapplying the protective wax or sealant as the level of protection fades.