In a previous post, we talked about the different finishes explaining the characteristics and composition of each of them, and the importance of correctly identifying them for profitability of the bodywork and paint shop.
The purpose of this article is to deepen the knowledge of the three-coat paint finishes, a paint system that is increasingly in demand among drivers due to its aesthetic appeal and spectacular nature.
What are Three-coat colours?
Initially, due to their high cost, three-coat colours were reserved only for premium and high-end cars.
However, over time, their use has spread among manufacturers. At present, practically all the big brands have this type of colour in their catalogue for their new models.
Despite having a higher cost compared to other finishes, the demand for the three-coat colours among drivers is becoming increasingly significant.
The spectacular finish and the vividness of the colour are some of the reasons why three-coat paint is becoming more and more popular.
On the other side of the scale are professional painters, for whom the complexity of the repair and the demand for optimal results in repainting is increasing.
This technological evolution of colour also entails a greater complexity and preparation, which will certainly have an impact on the time and cost of the repair.
It is therefore essential that professionals have the appropriate knowledge to tackle this type of work.
Applying solid colours to metallic colours is a step that already meant a major leap in the day-to-day running of the bodywork and paint shop.
The emergence of these new colours with metallic and pearl effect pigments (Colorstream, etc. Xirallic) have multiplied the work options and their difficulty. If we add to this the fact that each manufacturer can have a unique type of application for a colour formula, or use different basics to obtain the same result, the possibilities increase exponentially.
Coats involved in three-coat car paint
The three-coat finish is a type of car paint finish that consists of the following coats:
- First coat: a base colour coat, composed of different basics of the painting system. This will be in charge of providing the generic shade to the finish.
- Second coat: this coat’s composition may differ from one manufacturer to another. Some painting systems use a translucent colouring coat, which allows light to pass through and to be reflected on the base. For a greater simplification and swiftness in the process, at SINNEK we have developed an innovative application system that optimises colour matching in complex three-coat colours, based on a special base integrated within the W6000 series system, WS/6134 Transparent Red. This base provides many advantages over the traditional dyed varnish system, such as reduced costs and repair time or improved blurring capacity.
- Third coat: a final varnish coat that aims to provide the shine and protection required to the finish.
The main difference between two-coat and three-coat colours is that the latter provide greater colour vividness, a mix of depth effects and a variety of reflections.
Types of three-coat finishes
Depending on the type of pigmentation in both the first and second coats, three-coat finishes can be classified as:
Three-coat solid colour / pearl effect finish
This three-coat finish is usually used in red and yellow pearl colours, but especially in pearly whites.
It is undoubtedly the most widely used type of three-coat among manufacturers and consumers, and has become a trend, due to its colourfulness when exposed to a source of bright light such as sunlight. This is achieved by applying the following coats:
- A first coat for the solid colour base, within the grey scale, that will not have an impact on the final colour but serves to get the mixture.
- A second coat with a semi-transparent pearl effect, that gives depth to the solid base colour and reflections depending on the impact of light.
Three-coat finish with metallic or pearl base / solid effect
This option is becoming increasingly popular, and it is becoming increasingly common to see cars with this type of three-coat finish on the roads. This is achieved by applying the following coats:
- A first metallic base coat (usually silver), within the grey scale, that does not have an impact on the final colour but serves to achieve the mixture.
- A second coat of semi-transparent tinted varnish, that acts as an effect coat. This coat is composed of resin, along with basics or additives that provide colour. Although it is called a varnish or tinted lacquer, it actually works as a second colour base, which is uncatalysed and is applied before the lacquer. This coat will dye the metallic base coat, giving it a very striking metallic shine.
The best known three-coat finishes on the market include pearl reds like Ford’s Hot Magenta (9RTEWTA), green like the Ultimate Green (9GFE5ZA) and three-coat red like Peugeot’s Rouge Babylone or Citroën’s (LKR), Renault’s Rouge Flamme (NNP), Alfa Romeo’s Rosso Competizione (134/B) or Mazda’s popular Soul Crystal Red (46V).
How to repaint using a three-coat colour
SINNEK always focuses on following the data sheet specifications in terms of drying times, gun adjustment or application of the effect coat, in order to minimise the occurrence of possible errors in the repair.
Due to its greater complexity, three-coat finishing is a type of finish that involves more working time and cost of materials (effect coat materials, mixing container, etc.) than single or double coat colours.
The repair process involves the following steps:
1. Choosing the right colour version
To select the correct colour code, you must first know if the vehicle has been repainted or if on the contrary it keeps its original factory colour. If it has undergone any previous bodywork repairs, we recommend using the spectrophotometer for a correct colour reading.
This way, possible errors in colour matching will be minimised, thus obtaining a much more accurate colour information than if you took the colour card corresponding to the model’s manufacturing colour code as a reference.
2. Cleaning and degreasing of the surface
Thoroughly clean the surface to be repaired with degreasing agent and a dusting cloth.
3. Determine the number of coats with an effect to be applied on the base coat.
Conduct different colour tests on different test tubes.
This will allow you to adjust the final colour and know how many coats of the second base you should apply to get the best result. The test will consist in:
- Applying the first two-coat base (base coat) + stipulated evaporation time. In the SINNEK W6000 Series, this first coat is always activated, in order to ensure the stability and reaction of the process. You have 1 hour (depending on the room temperature) from the time you mix it with the activator.
- Apply a second double-coat base (number of coats depending on the colour) + stipulated evaporation time.
- Apply varnish + stipulated evaporation time.
Once all the test tubes are ready, compare them with the surface of the part to be repaired, to find out which one reproduces the colour most accurately, and how many coats is most suitable.
It is important that these tests are performed by the same technician who will repair the vehicle.
Each professional can apply the coats using a different distance or using a different movement of application, so the number of effect coats required may vary from one painter to another.
In addition, it should be noted that the coat thickness produced by a three-coat system will be much greater than that of other finishes.
If it is too thick, it can cause the water-based paint to contain some humidity, making it difficult to harden, and subsequently affecting the resistance of the topcoat.
To avoid this problem, following the evaporation intervals between coats recommended by the manufacturer is essential.
4. Priming colour according to the finishing colour
Do not use one type of priming colour per system, but rather adapt it according to the shade of the three-coat finish to be applied.
Thus, in a white three-coat colour we recommend always using a white primer, or in dark three-coat colours, a black or grey primer.
The main reason is that the three-coat colour applied on a similar shade of primer will require less coats to achieve a correct opacity and coverage, thus minimising the risks of obtaining an incorrect colour match or possible painting defects such as low gloss.
5. Three-coat colour application with blurring
Once the colour tests have been made in the test tubes, and you have chosen one of the versions, apply on the surface to be repaired.
As noted earlier, the possible differences in distance and speed of application and the coat thickness are factors that can produce colour differences.
Therefore, in three-coat finishes, a recommended practice is to apply the product using the blurring technique in order to minimise any possible matching error or colour leap, especially between parts and adjacent areas.
This type of practice is also recommended for two-coat finishes, with the exception that in a three-coat colour both the base and the effect coats must be blurred.
When blurring both coats, a larger area will be required for a subtle blurring, so you will use adjacent areas more often than in other finishes.
As you can see, three-coat finishes are undoubtedly more complex than other types of finish.
However, if you follow the paint manufacturer’s technical specifications and follow the times required for each process, any experienced professional will be able to obtain high-level colour matching results when faced with a three-coat colour repair.
Mastering its application will also have an impact on your workshop’s profitability, helping to increase productivity and efficiency.