Stone & rock chips are a very common occurrence, especially if your car does allot of miles, and once they begin to inflict your car, which usually happens around the font end, they can really begin to let down the overall appearance and leave it looking tired and neglected, even if it is fairly new or if the rest of it is in a good condition. Stone & rock chips can also lead to other damage such as clear coat flaking/failure and corrosion, as dirt and moisture can work its way into the chip and under the paint, and react with the metal panel underneath leaving unsightly rust spots. It is therefore important to pay attention to, and repair these damaged areas if possible, and the good news is that it can be done yourself fairly easily if you have access to the correct items and products.
There are generally two levels of stone & rock chip repair. The first kind is where the chip is simply covered with a matching colored touch up paint. This is far better than doing nothing and simply leaving the chip, as it protects the panel underneath from corrosion and the surrounding paintwork/lacquer from potential flaking/peeling, however usually the touch up repairs remain highly visible and can look very crude and unrefined.
The next level of repair is where, after touching up, the area is flatted and polished, in order to level the surface and remove any obvious sign of damage or repair. Before dealing with any stone & rock chip repairs it’s very important to ensure that the area is thoroughly cleaned in order to remove any road traffic film, contaminants, wax, grease or sealant so that the touch up paint can bond properly and the repair will last. A degreasing product, traffic film remover, or isopropyl alcohol can all be used for this.
After being thoroughly cleaned and dried, the area is ready to be touched up. You should source an identical colored touch up paint using your vehicles unique paint code in order to obtain a good match with the surrounding area. Most touch up paints and stone & rock chip repair kits come complete with a brush for application but these are usually highly ineffective and are typically the reason why people often make a mess of touching up cosmetic damage. Instead, a fine artists paint brush should be obtained from an art or model/hobby store and be used to apply the paint, as it will give you much greater control and more of a precision application.
The paint should be thoroughly shaken to ensure it is properly mixed, before being carefully applied in a light dabbing motion to the chip. Stone & rock chips usually do not go right down to the bare metal underneath but if you do have a severe chip it may require a primer base coat prior to the color being applied. These usually come with the repair kits but any appropriate automotive primer can be used. The touch up paint should be applied a number of times, following the paint manufacturers guidelines for drying times in between applications, building it up in layers so that it eventually sits up slightly higher than the level of the original paintwork.
This is the first stage of a stone & rock chip repair and it can be left at this, but preferably, you want to move onto the next stage, in order to fully disguise the chip and touch up. The newly applied paint should ideally be left for 24 hours to allow it to fully cure before any flatting or polishing is undertaken.
A fine grade wet and dry sanding paper then needs to be used to lightly sand over the touch up and level it with the surrounding area until it feels completely smooth to the touch. You only want to sand the touch up and a very small amount of the surrounding area so it is advisable to use something like a pencil, or even your finger with the paper wrapped over the end of it to provide you with enough control to sand only the localized area. Also, a suitable lubricant needs to be used when sanding, to help prevent excessive scratching and to help remove the paint and surface particles.
A soapy water solution or a detailing spray/clay lube are all ideal for this. Once all the touch up areas have been carefully wet sanded and wiped down with a clean, damp micro fiber towel, you will be left with flat, dull marks that will actually look worse than the original chips at this point, but do not worry as the final stage of the repair will eliminate this and restore the surface of your paintwork.
A dual action, or rotary machine polisher needs to then be used to polish out the sanding marks and restore the gloss and clarity to the surface. Usually, a cutting pad and fairly abrasive polishing compound are required to fully eliminate the marks, before moving onto a polishing pad and finishing polish in order to fully refine the finish if necessary. It really just depends on the extent of the repair and the tools and products being used, as to how much polishing work will be required. It should be noted here, that hand polishing alone will not be sufficient enough to remove wet sanding marks and so you should only wet sand your touched up areas if you have access to a suitable machine polisher.
After sufficient polishing, the area should be completely restored and the original chip should be indistinguishable from the rest of the paintwork. If you have metallic paintwork or if you are using a specific repair kit that comes with a lacquer, then you may need to apply it over the touched up area, allow it to completely dry and then repeat the wet sanding and polishing process again. After the repair has been completed, it is advisable to apply a high quality carnauba based wax, or a synthetic sealant to the area in order to further protect it from the elements and to lock in the new finish.
Clearly, prevention is better than cure and it is preferable not to let your vehicle get inflicted with stone & rock chips in the first place, so it is advisable to look into the many options that are available to protect either certain parts, or all of your vehicle from damage, such as paint protection films, car bras and vinyl wrapping.