A paint system establishes the paint technology that is used to coat a given object. In the case of vehicle refinishing, single-coat and two-coat systems are different. Each of these variants has specific characteristics, which is why knowing the differences between a single-coat and a two-coat system is necessary to adapt the work carried out to the required quality.
Do you know what differences we mean? If you don’t know what we’re talking about, don’t worry, we’ll list them for you below, and if you already know them, this will surely help you refresh your knowledge.
Differences between single-coat and two-coat systems
Both the single-coat and the two-coat system allow for painting an object to protect it and beautify it by giving it color and a given level of gloss. However, stemming from this similarity, there are differences between one painting system and another. These differences attend to different aspects of painting that affect the quality obtained, the durability of the coating or its environmental impact, among other things. Please find the most relevant ones in the following table:
1st difference – Definition:
2nd difference – Paint technology:
The second difference refers to the composition of the base. In the case of the single-coat system, it is a solvent base coating. On the other hand, the two-coat base can be either water or solvent-based, and in the case of clear coats, it is always solvent-based.
3rd difference – Harmful and polluting effect:
In the bilayer system, there are systems on the market that are not so respectful towards the environment, while there are others that are more compliant. With regard to environmental preservation, the water-based two-coat systems comply with the strictest regulations regarding environmental protection. Generally, in order to comply with restrictive legislation on environmental issues, we would use low-VOC clear coats. Single-coat systems.
4th difference – Environmental resistance of the paint:
Single-coat finishes are less environmentally resistant than two-coat systems, which are designed to offer increased durability. This means that over time and depending on weather conditions, they could degrade, losing brightness and showiness.
5th difference – Colorimetric limitations:
Single-coat finishes used in the automotive sector are only available in plain colors, which significantly narrows down the color palette and customization options. In the two-coat system, the colorimetric variety is very extensive. There are all kinds of plain colors, metallic, pearlescent and with special effects. Thanks to this, car owners enjoy many more options when it comes to customizing their vehicles.
6th difference – Main applications:
Due to their limitations, the current applications of single-coat bases are mainly focused on commercial vehicles and new cars, where the aesthetic aspect is not so important for the client (white, black, plain red, etc.). On the other hand, the two-coat system is used in finishes where the aesthetics sought cannot be achieved using single-coat finishes, such as metallic, pearlescent or candy colors.
7th difference – Preparation of primers:
Since they are coatings with a certain filling power, primer preparation in single-coat systems is less laborious than in two-coat topcoats. Generally, they cover sanding scratches up to P-400 dry. Normally, due to the particles and special finishes, in the two-coat system, the preparation is a little more rigorous to avoid scratches that we would not see in single-coat finishes. It is very common to use blending techniques in this type of topcoat. Thus, we will also carry out a specific preparation for this type of application.
8th difference – Application:
As a general rule, the application of single-coat colors is carried out in two coats. Both are applied using the same technique, and the only precaution to be taken is to avoid overloading the first one in order to cover the patch, since the coverage is achieved with the second coat. In two-coat colors, different applications may be identified
- The two-coat plain colors are applied in two coats.
- Metallic and pearlescent colors in two covering coats and a final mist coat, which is applied from a greater distance and using less pressure. The effect particles must be laid completely flat on the surface.
- Special effect colors are applied based on the manufacturer’s instructions and color type.
- The clear coat is applied after the application of the base coat.
9th difference – Color adjustment:
The adjustment of the single-coat colors is easier, since they do not include any type of effect. Matching the color of a two-coat base is more complex, especially when working with metallic, pearlescent and special effect colors. With two-coat matt topcoats, the adjustment of this type of clear coats is also a problem, since there are no specific tools to determine the level of gloss.
10th difference – Color:
The difference in tonality in these colors after refinishing is less frequent, due to the fact that there is less variety of colors and they do not integrate effects. The greater ease of color adjustment that characterizes them also reduces this risk. The wide range of colors and effects available means that there is a greater risk of color changes and the appearance of phenomena such as the flop effect. Therefore, it is essential to have specific tools that facilitate the color identification process.
11th difference – Correction of defects
In single-coat systems, we will usually use a sanding and polishing process that will allow for correcting the issue or defect. In the case of the two-coat system, the existing sanding margin corresponds only to the clear coat, so that if it is sanded excessively, rims appear on the base coat and repainting becomes necessary.
12th difference – Cost
The single-coat system has a lower cost since only one process and therefore one product is needed. In the two-coat system, the cost is higher given that a two-coat base and a clear coat need to be used.
Single-coat vs two-coat paint
The use of a single-coat or two-coat coating responds, fundamentally, to the type of work carried out. In this sense, the most demanding topcoats require the use of two-coat painting systems, while single-coat paints are sufficient for commercial finishes. In any event, if you are looking for the highest quality and greater durability, two-coat finishes may be the solution.