Damage or defects that appear on the car’s paintwork are the great enemy of the owner, but also of the painter, the bodyshop and for productivity. The occurrence of damage or defects spoils the visual appearance of the affected part, and represents an additional cost for the bodyshop when it is liable.
Two of these unwanted defects are paint discoloration and color change of the bodywork. If you are interested in learning more about them, here are some tips on how to prevent discoloration and color change in the bodywork.
What do we mean by discoloration?
Discoloration is defined as any variation or loss of color that occurs on a painted or unpainted surface. Thus, both painted bodywork components and unpainted plastic parts are susceptible to discolorations that change the original shade of color.
How does discoloration occur?
Discoloration of the surface is caused by different factors that alter the molecular structure of the different paints, either by attacking the color of the coating itself, causing it to yellow or lose its gloss. The most common conditions that cause these effects are the following:
- Weather factors. Dew, salinity and ultraviolet radiation are weather factors that, over the years, cause discoloration on uncoated plastic materials or on any painted component. These factors affect single-coat paints and single-component aerosol coatings to a greater extent, although the two-coat system is also affected when the clear coat used is of low quality. Discoloration is caused by a change in the shade of the paint that provides the color or by degradation of the clear coat (yellowing or loss of gloss).
- Low chemical resistance or low quality paints. Topcoats are classified into two-coat and single-coat systems. While single-coat topcoats have disappeared in the factory, they are still used in repairs due to their lower cost compared to the two-coat system. In spite of this very attractive advantage, the reality is that single-coat paints tend to fade over time because they offer lower chemical resistance than two-coat paints. Also other products such as low-quality clear coats or single-component textured paint aerosols for plastics offer more limited environmental resistance that can lead to color fading.
- Improperly performed repairs. Any vehicle driving on public roads is susceptible to some form of incident or accident that requires a subsequent repair. During this process, it is important for the operator to consider the need to use quality products and to apply them according to the manufacturer’s instructions. The clearest example of this is the excessive addition of hardener when the putty is mixed. This excess causes the pigment to redissolve with the subsequently applied layers of paint, causing the appearance of stains that are visually perceived as discoloration. It can also be caused by the use of unsuitable hardeners or from a poor application of metallic colors.
- Lack of coating on the parts. The application of paints on different surfaces provides a protective effect that prevents the weather (humidity, rain, salinity, sun, etc.) from damaging the base material. It is obvious that any vehicle bodywork comes factory painted, although in some versions the plastics come uncoated, a circumstance which, over the years, inevitably causes the plastic to age in the form of discoloration. This color change is quickly apparent when the plastics begin to turn a whitish color.
- Certain types of dirt. Despite the fact that the paint used in the automotive industry is very resistant, there are certain types of dirt that chemically attack the structure of the paint, leading to discoloration. Bird droppings, pine or acacia resin, insect remains or environmental pollution caused by certain industries (cement, concrete, etc.) are factors that can cause color changes on the paint.
- Inadequate cleaning. Paints are prone to getting dirty and certain dirt tends to remain embedded in them. This sometimes leads to the use of overly aggressive products such as acidic, alkaline or solvent cleaners to remove the most resistant material (tree resin, tar, etc.). Additionally, if these cleaners are not applied correctly, they can cause marks or abrasions on the paint that result in changes to the color shade, discoloration or appearance of stains and loss of gloss.
- Bodywork color. Some red, yellow, white and black colors used for bodywork painting absorb a higher amount of sunlight, resulting in a higher risk of localized color changes.
Tips for correcting and preventing discoloration and color change to the bodywork
The following table shows the most common causes of paint discoloration and how to correct and avoid the problem in each case:
Weather factors – Bodywork color
Correction:
- Discoloration due to loss of gloss: polish the surface.
- Discoloration of the color or clear coat: sand to remove and refinish.
Prevention:
- Protect the surface with wax or ceramic coatings.
- Refinish with quality products.
Low quality or low chemical resistance
Correction:
- Clean the surface, seal with specific primer, if necessary, and refinish
Prevention:
- Refinish with quality products.
- Follow the manufacturer’s instructions exactly.
Improperly performed repairs
Correction:
- Sand the surface, seal it with specific primer and refinish.
Prevention:
- Refinish with quality products.
- Follow the manufacturer’s instructions exactly.
Lack of coating on the parts.
Correction:
- Replace the plastic.
- Sand and paint it.
Prevention:
- Protect the plastic with ceramic coatings.
- Refinish with quality paints.
Embedded dirt
Correction:
- Option 1: Clean with cleaners specific to each type of dirt, decontamination with ferric cleaner or a clay bar, sand the damage, if necessary, and polish the surface.
- Option 2: (only if option 1 is not sufficient): sand and refinish.
Prevention:
- Clean as soon as it is detected.
- Frequent washing and periodic decontamination
- Protect the surface with wax or ceramic coatings.
- If repaired, use quality products and follow the manufacturer’s instructions.
Inadequate cleaning
Correction:
- Option 1: repeat cleaning with suitable products and/or decontaminating agents.
- Option 2 : polish the damaged area.
- Option 3 : only if option 2 is not sufficient: sand and refinish.
Prevention:
- Choose a suitable cleaning product.
- Acid or alkaline pH cleaners, do not let dry and apply in the proportions indicated by the manufacturer.
- Use microfiber cloths and do not rub the surface.
- If refinishing, use quality products and follow the manufacturer’s instructions.
Protect against paint discoloration
Paint discoloration is a defect that appears on the paint as a result of different factors. When it comes to repairing it, it is necessary to be certain of its origin in order to determine the causes and thus use the most appropriate correction and prevention methods. Any repair should be carried out with the most suitable products and always following the manufacturer’s instructions.
