Painting restoration is a complex technological process that requires not only expensive equipment, but also a deep understanding of the chemistry of materials. Quality of painting It depends on how accurately the master observes each stage, starting from cleaning the old layer and ending with finishing polishing. The slightest deviation from the regulations or violation of temperature regimes can lead to defects that will appear after a while.
Modern methods of painting allow you to recreate the factory coating, which cannot be distinguished from the original without special devices. However, to achieve this result, it is necessary to strictly control the humidity, temperature in the chamber and drying time of each layer. In this article, we will discuss professional technology in detail so that you understand exactly what you pay money for in the service.
Surface preparation and defects
The first and most critical stage is bodywork. It is from the quality of cleaning and degreasing that the adhesion of future layers depends. If you miss this stage, the paint can swell or peel off after a few months of operation of the car.
The wizard should carefully examine the car in bright side light to reveal all the hidden defects: chipped, scratches, dents and traces of corrosion. All these areas are marked with a marker for subsequent processing. It is important to understand that simply "paint" rust can not be - you need to completely remove the oxidized metal.
⚠️ Attention: If a through corrosion is found during cleaning, a simple putty will not help. Requires metal digestion or installation of repair insert, otherwise moisture will destroy the body from the inside under a new layer of paint.
Then mechanical cleaning of the repair areas is carried out. Grinding machines with abrasive circles of different grains are used. The transition boundaries between the old varnish and the new material should be smooth to avoid steps after painting. Finishing It is performed with a fine-grained abrasive that creates risks that are easily covered by the soil.
Spattle and geometry alignment
After removing the old varnish and revealing irregularities, the stage of restoring the geometry of the part begins. This is the purpose of the application putty, which come in different types: with fiberglass for deep dents, with aluminum dust for rigidity and finishing fine-grained.
Apply the material in thin layers, allowing each of them to dry. If you pile too much putty at a time, it may not dry inside or give a strong shrinkage, which will lead to dips on the surface. Mixing the base and hardener should be carried out strictly according to the manufacturer's instructions, using measuring rulers.
- 🧪 Proportions: violation of the ratio of the hardener will either lead to non-drying, or to excessive fragility of the layer.
- ⏳ Lifetime: the finished mixture must be applied in 3-5 minutes, after which it begins to harden.
- 🌡️ Temperature: Spattle is better carried out in a warm room, cold material does not lie down well and dries for a long time.
After drying, the surface is grinded. First, a rough abrasive is given the shape, then smaller risks are removed. The perfectly flat surface is checked tactilely or with the help of a developing powder, which shows all the holes and bumps.
Use a developing powder (dry developer) before grinding the putty - it will immediately show all irregularities that are not noticeable.
Grounding and isolation
Printing is the foundation for paint coating. Primary soil It is applied to bare metal to protect against corrosion, and secondary (acrylic) creates the basis for paint and hides the risks from grinding. The technology requires the application of 2-3 layers with interlayer drying.
It is important to choose the correct viscosity of the soil and adjust the spray gun. Too liquid soil can give underdrafts, and thick - "shagrin" (the effect of orange peel), which is then difficult to remove. The pressure at the exit of the gun is usually 2-3 atmospheres, but the exact parameters depend on the model of the sprayer.
| Type of soil | Appointment | Drying time (20°C) | Grinding |
|---|---|---|---|
| epoxy | Anti-corrosion protection | 12:24 hours. | Not grinding (painting) |
| Acid (phosphate) | Metal adhesion | 15-30 minutes | Not grinding. |
| Acrylic 2K | Alignment, the basis | 30-60 minutes. | Mandatory (P400-P600) |
After drying, the acrylic soil is grinded with an abrasive P400-P600 under enamel or P800-P1000 under metallic. Pollination It is not produced, its task is to be matte and homogeneous. Before painting, the surface is again thoroughly degreased with antisilicone.
Color selection and enamel coloring
Getting into color is both an art and a science at the same time. Even if the paint code is indicated on the body, the actual color may differ due to sunburn or the characteristics of the factory lot. Therefore, professional tin-tub It often requires manual fine-tuning.
The colorist mixes the components, paints the metal plate, dries it and compares it with a sample of a car under different lighting. It is especially difficult to work with three-component colors (trico) and complex pearls, where the shade depends on the viewing angle.
Why is the color on the plate and on the car different?
Metallic and mother of pearl are spatial structures. On a flat color, the particles are oriented differently than on the round surface of the body. An experienced craftsman does a "stretch" (spraying with different densities) on a test map to find the ideal angle of particle incidence that coincides with the body.
The finished paint is filtered through a strainer (usually 125-190 microns) before pouring into the spray tank. This is a mandatory procedure, as even a microscopic mottled mottled can damage the entire layer, creating a crater or bump.
Technology of coating paints
The painting process takes place in a special chamber, where dust is excluded. The air temperature should be about 20-22 ° C. Enamel application technology usually includes one or two cover layers and, if necessary, a base layer to create an effect.
The gun is held perpendicular to the surface at a distance of 15-20 cm. Movements should be smooth, with the overlapping of the previous passage by 50%. It is important not to stay in one place to avoid the stains. Interlayer drying It takes 10-15 minutes until the layer becomes matte.
- 🌬️ First layer: A subtle "ghost" is needed for adhesion.
- 🎨 Second layer: The main, covert, gives color.
- ✨ Third layer: (optional) to create a transition or saturation of mother of mother of mother of mother of mother of mother of mother of mother.
⚠️ Attention: Never try to speed up the drying of the base (enamel) with a hair dryer or an IR emitter before applying the varnish. This will lead to boiling of the solvent in the varnish and the appearance of microbubbles that will appear after drying.
After the base is completely dried (usually 20-40 minutes), varnish is applied. Lacquer protects color from ultraviolet light and mechanical influences. It is applied in 1.5-2 layers. The first layer is thin, the second is glossy, "sputter" (wet layer), which gives depth and shine.
☑️ Quality control of painting
Drying and polymerization of lacquer
The final drying can take place naturally or in a drying chamber at 60°C. Thermal drying accelerates the polymerization process, making the coating more solid and resistant. The drying time in the chamber is usually 45-60 minutes.
It is important to follow the temperature schedule. If you sharply heat fresh varnish, the solvent will begin to evaporate too quickly, forming a crust on the surface, under which the bubbles will remain. Therefore, first give 10-15 minutes for "study" at room temperature, then smoothly raise the heating.
After cooling the car, the coating is ready for operation, but full. polymerization All layers take up to 30 days. During this period, it is not recommended to wash the car with chemicals or expose the body to strong mechanical loads.
The quality of the varnish and the observance of drying time determine how long the car will retain its shine and whether the coating will not become cloudy in a couple of years.
Defect elimination and polishing
Even in ideal conditions, small specks or “shoots” may remain on the surface. Abrasive polishing is carried out to eliminate these defects. First, the surface is treated with P1500-P3000 grinding paper (wet grinding) to level the microrelief.
Then a polishing machine with circles of different rigidity and polishing pastes are used. First, a rough paste is used to remove risks, then thin for gloss guidance. Finishing polish It gives the coating back a mirror shine.
It is important not to overdo it and not to wipe the varnish to the base, especially on the sharp edges of the body (ribs of stiffness). These places are polished manually or with minimal pressure. After polishing, the body can be covered with ceramics or wax for additional protection.
How long does it take to paint the detail fully?
The full cycle, including preparation, putty, soil, painting and drying, takes from 2 to 4 days. This time is necessary for the quality drying of each layer. Accelerating the process at the expense of drying time is unacceptable.
Can I paint a car in a garage without a camera?
Theoretically, it is possible, but the quality will be low due to dust. The dust that settles on the wet varnish will spoil the view. A professional camera has an air filtration and extraction system, which eliminates this risk.
Do I need to take out the details before painting?
To obtain factory quality ("zero") it is better to remove pens, moldings and mirrors. Painting "with pasting" always leaves visible borders and improprieties in hard-to-reach places.