Recovery of a carβs paintwork is a process where accuracy is more important than speed, and knowledge of technology determines whether a part will shine for years or start peeling after a month. The question of how many layers of paint and varnish to apply, has no single universal answer, as it all depends on the type of materials used, color and painting conditions. Optimum thickness The coating is a balance between decorative properties and mechanical strength, the violation of which leads to defects.
Many beginners mistakenly believe that the more material is poured on the part, the better the protection, but this is not true. Excess thickness provokes the appearance of shashavens, subtricks and even detachments, and insufficient - lumens and weak cover. In this article, we will discuss the physics of the application process. ecrylic And varnish formulations so that you understand what exactly happens on the surface of the metal at the time of staining.
β οΈ Note: Non-compliance with the time intervals of interlayer drying (interlayer exposure) is the main cause of bubbles and βboilingβ of paint, regardless of the number of layers applied.
The structure of the ideal paint coating
Before talking about the numbers, you need to understand what the βcakeβ of the coating on the body of the car consists of. Modern LCP is a complex system where each layer performs a strictly defined function, and replacing one component with another is impossible. Primary soil (primer) is responsible for metal adhesion and anticorrosion protection, secondary soil (filler) equalizes the risks and creates a base, and then decorative layers go.
The decorative part consists of a base (colored pigment) and a varnish (protective layer). The base paint can be single-component (1K), where the pigment is mixed with the varnish, or two-component (2K), requiring separate varnishing. It is in the second situation that the question of the number of layers arises most acutely, since the varnish is applied on top of the dried base.
- π¨ Sound filler: It creates a smooth surface and prevents subsidence.
- π Basic enamel: gives color and visual effect (metallic, mother of pearl).
- π‘οΈ Acrylic varnish: protects against ultraviolet radiation, chemistry and mechanical damage.
The thickness of each layer is measured in microns, and the control of this parameter is carried out by a thickness gauge. For factory coating, 80-120 microns per parts are considered the norm, while for local repairs this figure can reach 150-180 microns without loss of quality, if the technology is complied with.
Technology of application of basic enamel (Bases)
Applying the base paint is the foundation for the final color. The number of layers of the base directly depends on the cover of the pigment and the desired shade. Usually painters apply two to three full layers, but there are nuances. The first layer, often referred to as a βfogβ or binder, is applied thinly to ensure adhesion to the soil and avoid solvent spikes.
Second and third layers They are applied wet, overlapping each other by 50-70%. It is important not to overdo it: if the layer of the base is too thick, the solvent will not have time to evaporate before applying the varnish, which will lead to clouding or bloating. For complex colors, such as red or yellow, an additional, fourth layer may be required for full cover.
βοΈ Control of base application
Particular attention should be paid to drying between layers. Interlayer drying It is usually 10-15 minutes at a temperature of 20Β°C. If you apply the next layer earlier, the solvent will βlockβ inside, if later β an oxide film can form on the surface, worsening adgzia. Visually, the readiness of the base for varnishing is determined by the matte shade: if glossy areas appeared, then the layer has not yet dried up.
How many layers of varnish are needed for the perfect result
Lacquer is the final shield of the car and its application requires jewellery precision. Standard technology involves the application of two full layers. The first layer of lacquer is applied finely, rubbing movements to create an adhesive bond with the base. The second layer is applied more abundantly, forming a coating body and glossy shine.
Some craftsmen practice applying 1.5 or 2.5 layers, especially if high-dry residue varnish is used (see below).HS-lac). In this case, the first layer is made binder, the second is fully wet, and the third (half-shaped) is made to align the shaverin and add volume. However, for beginners, the classic scheme of "two full layers" is recommended, since the risk of leakage at three layers increases many times.
| Type of lacquer | Recommended number of layers | Thickness of one layer (ΞΌm) | Features |
|---|---|---|---|
| MS (Medium Solid) | 2 full | 30-40 | Requires dilution, medium flow |
| HS (High Solid) | 1.5 - 2 | 40-50 | High dry residue, less shrinkage |
| UHS (Ultra High Solid) | 1 - 1.5 | 50-60 | Very thick, applied in one passage. |
| Ceramic | 1-2 | 2-5 | It is applied in micro-layers, requires polishing. |
When applying the second layer of varnish, add 5-10% of the diluent to improve the spreadability, but only if the manufacturer's instructions allow.
It is important to observe the direction of the spray gun. If the base has dried vertically, the first layer of varnish is often applied horizontally, and the second layer is applied vertically again to cover possible gaps. This provides uniform thickness and the absence of βappleβ (variousness when viewed from an angle).
Effect of paint type on number of layers
Different types of pigments behave differently. Solid colors (ordinary enamel without effects) usually overlap in two layers, since the pigment in them has a good covering ability. They are easier to work with, and the risk of getting stripes is minimal even for less experienced craftsmen.
The situation is changing with metallics and pearls. Here, aluminum particles or mica must fit in a certain order to give the correct glare. If you apply too many layers or make them too thick, the particles will sink into the solvent and lie down chaoticly, causing the color to become darker and lose depth. For such flowers, it is critically important. viscosity and exact observance of drying time.
β οΈ Note: When working with three-component colors (Candy), the number of layers of the base can reach 5-7, but they are applied in microscopic doses, otherwise the color will turn black.
The transparency of the base should also be taken into account. Some repair bases have high cover and allow you to close the ground in two passes, while cheap analogues may require a third layer, which increases material consumption and work time.
Common mistakes in applying LCP
One of the most common mistakes is to try to βpourβ the part with varnish the first time, ignoring the binder layer. This is almost guaranteed to lead to the formation of craters and bubbles, as air from the pores of the base does not have time to escape. The other extreme is the application of varnish on an undried base, which causes clouding (mattenness) of the entire coating.
Another problem is the lack of distance to the surface. If you hold the gun too close, there is an effect of βorange peelβ and staining. If too far - the paint dries on the fly, lying dry cereal, which then can not be polished. Distance 15-20 cm It is the best for most squirrels.
What do I do if I get a slack?
Do not try to remove fresh undertone with a cloth or finger - you will only make it worse. Let the varnish dry completely (it is better to leave for a day), then carefully cut the swelling with the blade level with the surface and polish this area. If the undertone is deep, local repainting will be required.
Don't forget to keep the cell clean. The dust that settles between the layers of varnish will spoil the whole work. Each extra layer increases the likelihood of debris getting into the area, so you should not aim for the maximum amount, but for the optimal thickness that provides protection and shine.
Quality control and final thickness
How do you know if there are enough layers? Visually, the surface should be evenly glossy, without matte spots and stripes. However, the best way to control is to use a thickness gauge. After complete drying (polymerization), the thickness of the varnish should be about 40-60 microns, and together with the base - 60-90 microns.
Exceeding the total thickness of the LCP above 200 microns (including soil) makes the coating brittle. When hit by a stone or deformation of the part of such a βcakeβ will crack to metal, while the thin factory coating can simply stretch. Therefore, the phrase βyou can not spoil porridge with oilβ in the painting business does not work.
- π Measure: Measure the thickness of the measuring device in 5-7 points of the detail.
- π Visual control: Inspection in bright side light will reveal a shaking.
- β³ Time: let the varnish gain hardness before polishing (usually 24 hours).
Gold standard repair: 2 layers of base + 2 layers of varnish give the optimal balance between color depth, protection and durability of the coating.
FAQ: Frequently Asked Questions
Can I apply the varnish in one layer?
Technically possible, using special UHS-varnishes with a high dry residue, but it requires high professionalism. For standard HS-varnishes, one layer will be too thin, it will quickly lose its shine and will not hide the risks of grinding.
How long after the base can you apply the varnish?
Usually the interval is 15-30 minutes at a temperature of 20 Β° C. The main sign of readiness - the base should become matte. If you swipe your finger in an inconspicuous place, there should be no paint on the glove, but the finger should be dry.
What happens if you apply 4 layers of varnish?
Most likely, the varnish will flow during the drying process or begin to boil. Excess thickness prevents the release of the solvent, which leads to the internal tension of the film and subsequent cracking or detachment.
Do I need to grind the base before the varnish?
No, the base enamel cannot be grinded. It has a porous structure for clutching with the varnish. Grinding will break this layer, and the varnish will lie with defects. If the base has landed dust, it can be neatly removed with a sticky napkin, but not sandpaper.