High-quality painting of the car is a complex technological process that requires not only expensive equipment, but also strict adherence to the sequence of operations. Many owners of vehicles mistakenly believe that the restoration of paintwork is limited only to the application of finishing enamel, but it is the preparatory work that determines the durability and appearance of the result. Disruption of technology at any stage can result in defects such as shaking, craters or peeling off of material.
In the professional environment of body repair, a clear algorithm of actions is distinguished, ignoring which is unacceptable. Painting of auto stages of work include surface preparation, removal of irregularities, insulation of repair areas and multilayer application of materials. Each layer performs its function, from adhesion to corrosion protection to deep color creation. Understanding the physicochemical processes that occur when materials are drying allows the master to avoid common mistakes.
This article is a detailed guide that will reveal the technical nuances of each step. We will look at how to properly prepare the metal, what tools are needed for grinding and why the temperature regime in the paint chamber is critical. Whether you plan to contact the service or do the work yourself, knowing the theory will help you control the quality of the execution.
Dismantling of elements and primary surface preparation
The first and one of the most time-consuming stages is the dismantling of the hinged elements of the body. To obtain a qualitative result without the boundaries of transition and dust, it is necessary to remove handles, moldings, mirrors, headlights and bumpers. Experienced painters know that the coloring "discussion" allows you to apply the material in hard-to-reach places and avoid visible joints. Left in place rubber seals can become a source of moisture under a new layer of paint in the future.
After dismantling, the body is thoroughly washed using degreasing compounds. This is necessary to remove bitumen stains, silicone contaminants and road dirt. It is important to use special degreasing agents that do not leave the film and completely evaporate from the surface. Residues of oils can lead to the fact that the soil or enamel simply does not lie on the metal, forming a “fish eye”.
⚠️ Note: When using aggressive solvents for degreasing, be sure to check their compatibility with plastic body elements so as not to damage their structure.
Next is the assessment of the condition of the paintwork. If you plan a complete repainting, the old lacquer is completely coiled. In the case of local repairs, the boundaries of the old coating are expanded and sanded to create a smooth transition. adhesion Materials directly depend on the quality of mechanical surface treatment.
Corrosion removal and alignment of body geometry
If there are corrosion foci on the body, they must be removed to pure metal. Rust tends to spread under a layer of paint, so surface treatment is ineffective here. Mechanical cleaning methods are used using grinding machines and abrasive circles. Deep lesions of the metal may require cutting out damaged areas and welding new rempleks.
After stripping the metal, it is often necessary to restore the geometry of the part if it has been deformed as a result of impact. For this purpose, slips and hydraulic stretch marks are used. Correction of the metal is a critical step, since applying thick layers of putty on a curved surface will not solve the problem, but only create the appearance of flatness. Body metal It must be in the correct shape before any chemical compositions are applied.
Acid soil (phosphate) is applied to the cleaned areas, which prevents the re-emergence of corrosion. It creates a thin film that provides a chemical bond of the metal with subsequent layers. Skipping this stage when working with bare metal is considered a gross technological error.
Use indicator oil when working with a rye hammer to visually control the treated area and not overheat the metal.
Spattle and grinding: creating the perfect plane
Spattle is necessary to eliminate micronervousnesses that cannot be removed by a richt. At this stage, a car putty is used, which is selected depending on the depth of the defect. For deep dents, compositions with aluminum powder or fiberglass are used, and for the final alignment, soft finish putty shoes are used. It is important to observe the mixing proportions of the base and hardener specified by the manufacturer.
The process of grinding the putty requires the use of bars and abrasives of various grains. Start with a large grain (for example, P80 or P120) to form a circuit, gradually moving to a smaller one (P240, P320). Grinding It should be carried out by cross movements to control the plane and not create holes. The use of a developing powder helps to see all the irregularities that need to be improved.
The quality of grinding directly affects the appearance of the finished part. Any scratch from a large abrasive left under the ground will appear after painting under the influence of temperature and solvents. Therefore, the transition to the next stage is possible only after reaching a perfectly smooth surface.
☑️ Quality control of spatula
After grinding works are completed, the surface is again degreased and blown with compressed air. The dust left in the pores of the putty can cause defects when applying the soil. Therefore, cleaning is given special attention.
Body grounding and insulation of repair areas
Printing is the link between the prepared surface and the finish enamel. Acrylic soil-filler is applied in 2-3 layers with interlayer drying. Its main task is to fill the risks from grinding, level the microrelief and provide uniform coverage. Thickness of layer soil should be sufficient for subsequent grinding, but not exceed the permissible standards to avoid detachment.
An important point is the isolation of areas that are not subject to painting, as well as the creation of a smooth transition (stewing) between the repaired site and the old coating. For this purpose, special solvents and abrasives are used, which blur the border of the old varnish, making it invisible after painting.
⚠️ Attention: Before applying the soil, make sure that a high-quality moisture separator is installed in the compressor air supply system, since the oil hitting the surface will lead to a defect.
After drying, the soil is also subjected to grinding. Usually used abrasives P400-P500 under enamel or P800-P1000 under the base. Grind it carefully so as not to wipe the layer to the metal, especially on the ribs and sharp edges of the part. In case of tiring, the defect must be subtracted locally.
Why is it important to choose the right soil?
Some soils are incompatible with certain types of putty or enamels. For example, applying acrylic enamel to incompatible soil can cause a chemical reaction that leads to wrinkling of the coating. Always check the technical maps of the materials.
Preparation for painting and setting up of equipment
Final preparation before applying enamel includes thorough cleaning of the chamber from dust, blowing the part and re-degreasing. Special sticky wipes are used, which collect the smallest villi and dust. Cleanliness At this point, it is the number one priority, as any mottled material will spoil the glossy layer.
Setting a spray gun is an art that requires understanding the viscosity of the material and air pressure. The spray torch shall be adjusted so as to ensure uniform distribution of the paint without dry stains and stains. The distance to the surface and the speed of the hand of the master also play a key role.
| Parameter | Description | Impact on outcome |
|---|---|---|
| Air pressure. | The power of pushing paint out of the dusa | Affects the size of the torch and the degree of spray |
| Breadth of torch | Coverage area per pass | Determines the speed of work and uniformity |
| Submission of material | The amount of paint per unit time | Regulates the saturation of the layer and the risk of subtricks |
| Viscosity | The thickness of diluted paint | Critical for spouting and drying time |
Coloring paint is done either manually or by a computer program. Getting the exact color hit is a difficult task, especially for cars with age, as the factory color could burn out. Therefore, computer selection is often required taking into account the fading of the old coating.
Proper tuning of the spray gun and cleanliness in the chamber is more important than expensive paint. Marriage due to dust or an incorrect torch is almost impossible to fix without repainting.
Applying enamel and lacquer coating
The process of applying the base (color layer) occurs in several stages. The first layer is made thin, "dusty" to provide adhesion. The subsequent layers are applied more saturatedly, overlapping the soil and creating a uniform color. Between the layers, exposure (Flash-off time) is required to evaporate the solvent, usually 10-15 minutes.
After drying the base enamel (it becomes matte), varnish is applied. The lacquer protects the color from ultraviolet light and mechanical influences, and also gives depth and gloss. It is applied, as a rule, in two layers: the first is a thin binder, the second is a complete one, forming the coating body. It is important to avoid drying between layers of varnish to avoid the problem of interlayer adhesion.
The temperature in the chamber must be strictly observed. It is usually +20...+25°C. At low temperature, the varnish may not spread and remain matte or go shaking, and at high - dry too quickly, without having time to form a smooth surface. Time to dry It also depends on the type of hardener (fast, normal, slow), which is selected depending on the volume of the part being painted and the temperature in the chamber.
⚠️ Warning: When working with two-component varnishes and hardeners, be sure to use a respirator with carbon filters. The isocyanate vapors contained in hardeners are toxic and can cause serious respiratory diseases.
Finishing and polishing
Even in ideal conditions, after painting, small defects may remain on the surface: dust, shashashare (“orange peel”) or small decasses. To eliminate them, the finishing polish is carried out. This step begins after the complete polymerization of the lacquer, which can take anywhere from a few hours to several weeks depending on the materials.
The polishing process involves abrasively grinding the surface with water or dry using P1500-P3000 abrasives. This allows you to cut the top uneven layer of varnish and level the surface to the perfect gloss. Then the surface is polished with a machine using pastes of various abrasiveness.
The result of proper polishing is a deep, mirrored shine that hides the traces of repair. Polishing Not only does it improve the appearance, but it also seals the surface layer of the varnish, making it more resistant to scratches. The final touch is often the application of protective waxes or ceramic compounds.
How do you tell a shashavel from a dust?
Dust is solid particles protruding above the surface that can be felt with the nail. Shagrin is an uneven spread of lacquer, forming bumps that are part of the coating itself, not a foreign body.
Frequently Asked Questions (FAQ)
How long does it take to paint the car completely?
The time depends on the amount of work and technological pauses for drying. On average, a full cycle, including preparation, putty, primer and painting, takes from 5 to 10 working days. Accelerating the process with IR-drying lamps can shorten the time, but requires caution.
Can I paint a car in a garage without a paint camera?
Theoretically, it is possible, but the quality will be much lower. The lack of air filtration will cause dust to settle onto fresh paint, and the inability to control temperature and humidity can cause drying defects. Garage painting requires a minimum: clean room, good lighting and ventilation.
What is a transition and why is it needed?
The transition (or stub) is the area where the new paint smoothly merges with the old. It is necessary for local repairs so that the eye does not notice the boundaries between the new and old coating. It is done by special application of the base and varnish with access beyond the repaired zone.
Do I need to remove all the old varnish before painting?
With full repainting, yes, the surface is completely rewound. When local repairs, only varnish is removed in the damage zone and a transition to the surrounding area is made. If the old varnish is well maintained and has no cracks, its complete removal is not required, it is enough to create an adhesive layer.