Sistemas de acabado de pintura en automoción

During the inspection and assessment of the vehicle’s damage, it is essential to correctly identify the type of finish of the paint. This step will provide you with relevant information during the pre-repair phase, enabling you to assess its scope and complexity more accurately.

Therefore, it is essential for the professional painter to have an in-depth knowledge of the different finishing systems of a car paint.

How are car paint finishing systems classified? 

A vehicle’s paint system is classified according to its number of finish paint coats (colour and clear coat). The use of one type of finish or another will be determined by factors such as the type of vehicle to repair, the aesthetic appearance you wish to achieve or the application system used.

The most commonly used automotive paint systems are single layer base coat, two-coat and three-coat finish, the painting process being adapted in accordance with that applied in the repair. 

Capas de pintura para coche

It is essential for professional bodywork and paint shop to know them in depth, in order to optimise the repair time and product and tool costs.

Pigment types in car paint 

In order to better understand the different coats that make up a vehicle’s paint coat, you must first know what each coat contains and what its properties are.

In general terms, car paint is composed of pigment, which is the element that transfers colour, and gloss, which is provided by the resin that is also part of the paint.

Pigmento Color Pintura

In most cases, different pigments will be differentiated from others depending on the type and number of special particles they contain:

Solid pigments 

These pigments are composed of organic and inorganic particles that provide high opacity and coverage (one of the main fundamentals of painting). In addition, they allow to obtain practically all effect-free shades and achromatic colours, from primary to secondary. 

Special pigments 

Also called “Flip Flop”, “Chameleon” or “Iridescent Chromatic”. They provide chrome effects, sidereal effects, even temperature-sensitivity. They give rise to xirallic-type of colours. 

Metallic pigment 

Aluminium particles that provide a higher opacity and a metallic aspect to the paint. Depending on the size of these particles (fine, medium and coarse) it will provide a different reflection and shape (irregular or lenticular for colours that shine more brightly). 

Pearl pigments 

Manufactured from natural shiny “MICA” particles coated with metal oxides (titanium), which, depending on the number of coats, grant different interference, absorption and reflection phenomena. This type of pigment is also known as pearlescent

Efectos en la pintura por la reflexión de la luz
Impact of light on different types of colours

Paint coats on a new car 

In order to be able to correctly differentiate the different finish coats, it is convenient to know the substrates that make up the complete coat of paint of a newly manufactured car that has not been previously repainted. 

Capas de pintura que componen un coche

The type and number of substrates will also vary depending on the type of material the paint is to be applied to (steel, aluminium or plastic). Generally, a coat of paint on sheet metal will consist of:

  • Original horizontal coat thickness: 140 microns. 
  • Original vertical coat thickness: between 90 and 120 microns. 
  • Phosphating and passivating:provides anticorrosive protection and excellent adhesion. 
  • Cathodic electrophoresis: aqueous solution with + and – charged anticorrosive pigments. 20 microns. 
  • Filler: provides uniformity and adhesion to the finish coat. 40-50 microns. 
  • Finish: 
    • Single layer base coat: 40-50 microns 
    • Two-coat: 15 + 35-micron clear coat 
    • Three-coat: 15+15+ 35-micron clear coat 

Types of paint used in car repainting

The process involving repairing and repainting a vehicle generally includes the types of paint used according to their position from the topcoat paint: intermediate coat and finish paint. 

Intermediate coat or insulation paints 

This is the first coat of paint. It provides protection to the metal and the necessary anchoring to the finish paint. An incorrect application of this paint will impact on the finish paint, on its matching, coverage or possible appearance of different painting defects

Aplicación masilla pintura de fondo

This type of paint includes products such as polyester putties, fillers, primers, adhesion promoters or elasticisers, among others. 

Finish paints 

As its name suggests, the finish paint is the topcoat of paint on the surface

Its purpose is to give colour, brightness and effect so as to reproduce the vehicle’s original appearance. It also has a protection function against possible surface damage caused by chemical or mechanical agents. 

Types of car paint finishes 

As mentioned above, finishing systems are classified according to the number of coats they have: 

Single layer base coat finish 

This is a finish that is obtained with a single coat. All the components required (colour, gloss level, chemical-mechanical and UV resistance) are mixed in it.

This coat alone provides all the final appearance and paint protection features.

  • Advantages: fast application. High hardness. More cost-effective. 
  • Disadvantages: lower chemical resistance and less variety of colours (metallic or pearl colours can be achieved, but in smaller quantities). 

Two-coat finish 

It is currently the most commonly used finish. It consists of two coats, a first coat that provides the colour and effects, and a second coat that provides the gloss and the chemical and mechanical resistance required for its protection.

Capas del sistema bicapa pintura coche
  • Advantages: standardised, fast and cost-effective process. All colours available, including plain, pearl or special effect colours.
  • Disadvantages: higher cost and more complex application than single layer base coat paint. 

Types of two-coat finishes depending on the pigments and resins: 

  • Two-coat solid effect paint: two-coat finishes without any effect (white, red, blue, etc.) 
  • Two-coat metallic effect paint: finishes with metallic pigments and generally small proportions of solid pigments that give the shade. 
  • Two-coat pearl effect paint: this type of finish usually includes solid, metallic, pearly and even xirallic pigments. It is the two-coat that is mostly used today. 

Three-coat finish 

This finishing system consists of 3 layers.

Capas en un sistema tricapa de pintura
  • Intermediate coat colour.
  • Special effect colour (transparent coat that allows light to pass through and reflects the intermediate coat).
  • Clear coat (in some cases, the first clear coat layer is dyed with a special pigment). 

The following advantages and disadvantages of the three-coat system stand out:

  • Advantages: very bright colours, effects and reflections impossible to achieve with any other finish. 
  • Disadvantages: higher cost and complexity of matching compared to other finishing systems. 

Methods to differentiate between different types of finishes 

Different methods can be used, depending on the level of experience of the professional and the accuracy of the information to be obtained, from less to more reliable: 

Human eye

A professional painter with extensive experience will be able to tell at a glance whether the colour is solid, metallic or pearly, and the different types of finish. 

The greatest difficulties can be encountered when distinguishing between single layer base coat and solid two-coat finishes, or between pearly two- and three-coat finishes. Of course, this method is the one that can lead to more diagnostic errors. 

Identification sanding 

Another alternative would be to gently sand down an area of the surface you want to identify. This way, if the sanding remains are whitish, you know that the last coat that was applied is clear coat (two-coat). On the other hand, if the remains obtained are powder of the colour of the vehicle, you would be looking at a single layer base coat finish.

However, this method is not as effective in differentiating a two-coat finish from a three-coat finish, as both have clear coat as their topcoat.

Colour formulation 

In case of doubt, the unmistakable way to establish the pigments that are present and therefore the type of finish, would be by the colour formulation.

Como medir el color con el espectro

SINNEK recommends using this method since, in addition to correctly identifying the finish, you will obtain information about the mixture and its composition. 

  1. If the formula contains only conventional basics in the mix, it will be a smooth two-coat. 
  2. If the formula contains metallics but not pearls, it will be a metallic two-coat. 
  3. On the other hand, if the mixture contains some basic pearly, you will be looking at a pearly two-coat. 

In case of doubt, you can check this using SINNEK’s colour management software. You can also view our tutorial on how to use the spectrophotometer for colour measurement.

Benefits of knowing the different types of finishes for a workshop’s profitability 

Correctly identifying a car’s finish in the assessment carried out prior to a repair is essential for handling the work to be done in the most profitable way. 

An expert eye, like that of a professional painter, can tell the difference between metallic and pearly particles with the naked eye because of the different brightness and shade they provide.

But there may be other profiles within the workshop, such as the manager or the supervisor, who do not have the identification skills that work experience provides. 

Knowing a car’s paint finish will help you determine:

The cost of materials and time to be spent on the work 

Depending on the car’s finish, you will have to invest more or less time, which will have an impact on the cost/hour ratio. Generally, a single layer base coat paint repair will be less costly in time and product than a two or three coat repair. 

Nowadays there are different methods to know the exact type of finish. This will minimise possible errors during the repainting process, and will give you more time and confidence to plan each repair. As mentioned above, the use of a spectrophotometer is currently the most reliable method.