Study Guide: Paint Correction and Protection, Part I

Two of the International Detailing Association’s Certification Tests contain an extensive overlap of knowledge. The “Paint Correction and Protection” and the “Detailing Terminology” tests bothrequire an extensive understandingof OEM paint technology, common paint problems and their solutions, and chemicals and equipment used by detailers on vehicle paint. Thus, for the next couple of entries of the Study Guide, I will be discussing the topic of vehicle paint.

So, as you are studying for the Paint Exam, the terms that you are learning will help you with the Detailing Terminology Exam.

In this month’s column, I will spend most of the time describing common paint problems, which fall into two categories. There can be contamination on the surface, and there can be damage that goes into the paint layers.


Surface paint problems include environmental fallout, ferrous oxide deposits (rail dust), paint overspray, bug and tar splatters, cement splatters, and water spots.

Environmental fallout is a generic term that refers to all of the particulate crud that is floating around in the air. This stuff settles down onto the paint surface of the vehicle as it sits outside in the open air. Things like volcanic dust, jet fuel, paint droplets,industrial particulates (e.g., sanding and grinding debris), and any number of atomized chemicals released from industrial operations.

Most of this stuff by itself is not a problem for the paint, but when combined with water from precipitation or dew, most environmental fallout becomes fused with the surface of the paint. Sometimes, the result is water spots, which are mineral deposits on the surface of the paint. In the extreme case, like acid rain, the fallout and water combination actually etches into the paint, creating a sub-surface problem (more about this later). It is difficult to distinguish between water spots and water etching until the technician actually works on the area with detailer’s clay or compound.

Water spots are left on the surface when water droplets are allowed to dry on the vehicle’s surface. The spotting is caused by leftover minerals and other solids that are contained in most tap water. As the water dries, the minerals settle onto the paint surface, leaving rings the size of the original water drops.

Paint overspray, which is tiny droplets of atomized substances such as paint mist that settles out of the air onto automobile surfaces appearing as tiny speckles, also sticks to the paint. Most overspray can be removed using detailer’s clay, but sometimes wet-sanding and buffing are necessary.

Iron oxide deposits are a specific form of environmental fallout that are made up of tiny iron particles that come from industrial operations. You may have heard the term rail dust, which refers to the ferrous oxide particles that come from railroads. As the trains run along the rails, the contact and friction between the steel wheels on the train cars and the iron rails causes small,almost microscopic pieces of iron to spit out and float away in the air.

Iron oxide particles can also come from other metal-working industries such as ship-making. They appear as small brown nibs on the surface of the paint. Sometimes, especially on white vehicles, there is a brown ring surrounding the particle. The total width of the ring is less than 1/32 of an inch. On darker vehicles, the iron particle might be surrounded by an iridescent ring. Typically, iron oxide particles can be removed with detailer’s clay, but sometimes a portion of the particle can remain imbedded in the paint, requiring more aggressive cleaning techniques like acid washing.

Another surface paint problem is orange peel, the nubby rough appearance of paint that looks much like the texture of the skin of an orange. It is an artifact of the painting process and can cause the paint surface to be less reflective. Orange peel can only be removed by wet-sanding (sometimes known as “color sanding”).

Cement splatters are difficult to remove. The best way I have found is to first spray the cement with a citrus-oil-based cleaner. The cleaner will partially penetrate the cement and help to loosen it. Use a plastic spatula oryour fingernail to gently scratch off the cement. The oil in the cleaner will lubricate the paint surface, helping to reduce scratching. Unfortunately, some scratching of the paint is inevitable. So it’s necessary to polish the area after the cementhas been removed.

Removing bugs and tar can be accomplished with one of the many chemicals designed just for these contaminants. If the contamination is light, simply pour the chemical on a towel and wipe the affected area. If the contamination is heavier, it may be necessary to use a non-scratching scrub sponge to help agitate away the tar or bugs. Always apply wax to the cleaned area, as most of these chemicals will remove any existing wax.


Sub-surface paint problems occur when the damage goes below the surface of the paint. Such damage includes oxidation, scratches, chips, staining, and etching.

Oxidation is a condition of automotive paint in which certain chemical substances within the finish attach to oxygen molecules in the air over time, causing the paint surface to become dry, dull, and sometimes “chalky.” Put more simply, it is the drying out of the paint. Paint starts out as a liquid that is sprayed ontothe car. The paint quickly dries to the point that it feels “solid.” But the paint never stops drying out. The liquids that made up the paint before it was sprayed onto the car continue to evaporate, albeit at a slower and slower rate, over time. Without regular waxing, and after many years or heavy exposure to heat and sunlight, the paint will dry to the point that it becomes dull.

In single-stage paint systems, oxidation can be mostly removed by compounding or polishing the paint surface, which removes the “dead” paint. On clear-coat paint systems, oxidation appears as cloudiness in the clear coat (not the basecoat). Unfortunately, clear-coat oxidation begins deeper in the paint and is virtually impossible to remove.

Another paint problem that is caused by age is paint cracking. Sometimes called “checking” or “crazing,” it is caused when the layers of paint expand and contract at different rates, causing one of the layers to split or crack. These small cracks appear similar to a dry lakebed on the surface of the paint, in a random, multi-directional pattern. They can be quite deep into the paint surface and generally cannot be fixed with standard detailing techniques.

Scratches are essentially small gouges into the paint. Scratches can fall into one of three categories: micro-scratches, moderate scratches, and deep scratches. Micro-scratches are super fine scratches caused by light contact like normal washing. These types of scratches, which some people call “cob-webs” or “spider webbing,” are typically only visible in sunlight.

Swirl marks are another form of micro-scratches that are caused by aggressive buffing with a simple rotary (high-speed) buffer while using abrasive cleaners or compounds. For this reason, they can be considered “technical” micro-scratches because they are caused by the detailing technician. Swirl marks appear in the shape of circular arcs while non-technical micro-scratches have a much more random pattern. All types of micro-scratches can typically be removed with light polishing, for example by using a swirl-removing polish and a foam polishing pad.

Moderate scratches are those that can be removed or at least made to look less noticeable. These are often caused byincidental contact with the paint, like rubbing up against a side panel with a gym bag or sliding a box onto the trunk. Deep scratches are those that are downto the basecoat or primer. Unfortunately, these cannot be removed, nor can theybe made to look less noticeable using standard detailing techniques.

Other sub-surface problems include staining and etching, which can be caused by acid rain, bird droppings, and engine fluids. Etching is when the surface contaminant eats away at the paint. Bird droppings and eggs are famous

for this. It is difficult to repair etching, especially if it is deep into the paint. Acid rain is natural precipitation contaminated with acidic compounds from industrial pollution. It can cause damage like etching or discoloration of automotivefinishes and glass. The best solution isprevention — educate your customers on the importance of regular waxing or sealant application.

Paint chips or nicks are caused by sharp impacts like rocks or keys or other car doors. Some nicks can be improved using remedies similar to those used for scratches. Chipped-off paint, however, cannot be improved using standard detailing techniques. Instead, professional touch-up paint techniques can be used to fill in the chip, making it less noticeable.


There are many ways that paint can become damaged. Often there are several types of damage that, combined, cause the paint to look dull and old. Understanding the types of damage, and then using the correct chemical, equipment, and technique to correct the damage can go a long way to making most cars look great.

The International Detailing Association offers its Certified Detailer program to both members and non-members. It is the only independent certification currently available to professional detailers. The program currently consists of 10 tests that assess the taker’s background knowledge of detailing. This month’s column is one in an on-again, off-again series that is designed to present a study guide for those interested in taking the tests. Get more information or sign up for the tests at

Prentice St. Clair is president of Detail in Progress, a San Diego-based automotive reconditioning consulting firm. To contact him, e-mail or call (619) 701-1100.