Local paint restoration is a skill that allows the car owner to save significant money on specialized services. Often small chips, scratches or abrasions do not require complete repainting of the part, but they cannot be left unattended due to the risk of metal corrosion. Modern technologies make it possible to achieve factory-quality coatings if you approach the issue of choosing materials wisely.
The key step here is selection of paint in cans, since the final visual result depends on the matching of the shade. A mistake at this stage will result in the repaired area appearing as a “foreign” stain, negating all polishing and surface preparation efforts. Automotive enamel is a complex chemical composition that fades and changes its properties over time, so simply buying a can of paint “by eye” at an auto parts store is a risky undertaking.
In this article we will analyze in detail the process of color identification, methods of computer tinting and the nuances of self-coloring with aerosol materials. You will learn how to find the color code on the body, the difference between base and varnish, and what tools are needed to obtain a smooth surface without streaks or shagreen.
Color identification: code search and catalogs
The first and most important step is to determine the exact factory shade of your vehicle. Manufacturers assign each color a unique paint code, which allows you to recreate an identical mixture of pigments. This code does not need to be guessed or visually selected; it is indicated on a special plate or sticker located in certain places on the body.
Most often, the information is located on the driver's side pillar, under the hood on the engine compartment bulkhead, or in the trunk. For brand cars BMW the code is usually located on the counter, and Volkswagen it can be found in the spare wheel well or in the service book. It is important not to confuse the color code with the VIN number or trim code.
If the plate has become unreadable due to age or damage, the code can be found through the dealership by providing the vehicle's VIN code. There are also online catalogs and databases where you can find the desired number by model and year of manufacture. However, remember that over the years of use, the factory paint may have faded, and the new can of code may differ from the current condition of the body.
⚠️ Warning: Do not rely solely on the color name (such as “Black Magic” or “Crystal White”). The same name can be used for different shades in different years of production of the same model.
After receiving the code, you need to understand the type of paint. It could be acrylic enamel, which does not require varnishing, or “metallic” and “pearl”, which must be varnished for protection and shine. Incorrect determination of the type will result in the surface being matte or, conversely, too glossy at the repair site.
Selection methods: ready-made solution or computer tinting
There are two main ways to obtain paint in an aerosol can: purchasing a ready-made factory can or ordering individual computer tinting. Finished cylinders are produced in large batches strictly according to the manufacturer’s recipe for a certain year. This is a cheap and fast option, but it has one critical drawback - it does not take into account the fading of the old coating of your car.
Computer tinting in a specialized studio allows you to create a mixture that is as close as possible to the current state of your car’s paintwork. The master colorist mixes base pigments by weight, using a spectrophotometer or visual assessment of colors. This is especially true for complex colors such as knitwear or xserial, where the hue depends on the viewing angle.
When ordering tinting in a can, it is important to consider the volume. For local repair of chips and scratches, 150–200 ml of base is usually sufficient. If you plan to paint an entire part, for example, a door or wing, it is better to take 400–500 ml in order to have a reserve for overlapping and possible errors during spraying. Spray cans for car enamels are often equipped with special nozzles that imitate the torch of a spray gun.
The cost of individually selected paint is higher than that of a ready-made factory version, but the result is worth it. You get a material that, after polishing the transitions, becomes almost invisible. While the factory cylinder can give a noticeable difference of half a tone, especially on cars older than 3-5 years.
Why does paint fade?
Automotive enamel is exposed to aggressive effects of ultraviolet radiation, temperature changes, acid rain and reagents from roads. Pigments, especially red and black, lose their saturation over time, and clear varnish turns yellow or cloudy. This is why new factory code paint often looks brighter than the old body.
Required materials and surface preparation
A high-quality result is impossible without careful preparation. Even perfectly selected paint will not adhere well to a dirty, greasy or non-greased surface. Before starting work, it is necessary to prepare the repair area by removing rust, old peeling coating and dirt.
To work, you will need a set of abrasive materials. Start sanding with P320 or P400 grit, gradually moving to P600 and P800 to create a smooth transition. If there is exposed metal, it will need to be primed with an acid or epoxy primer to prevent corrosion from occurring under the new coat of paint.
Degreasing is a mandatory step that should not be skipped. Use special anti-silicones that do not leave streaks. Regular benzine or thinner may leave a greasy film, resulting in enamel peeling or fisheye craters immediately after application.
☑️ Checklist for preparation for painting
In addition to paint and primer, you will need: masking tape, covering paper or film, dust removal wipes, and possibly thinner if the consistency of the paint in the can seems too thick for your spray bottle (although this is rare in ready-made aerosols).
Technology of applying enamel from a spray can
The painting process requires care and adherence to temperature conditions. The optimal ambient temperature is from +18 to +22°C. At lower temperatures, the paint takes longer to dry and may lose its shine, and at high temperatures it can set too quickly, forming “shagreen” (orange peel).
Before application, the can must be shaken vigorously for 2-3 minutes to mix the balls inside and lift the settled pigments from the bottom. The first layer is applied with a very thin, so-called “dusty” layer. It serves to improve adhesion (adhesion) and should not completely cover the surface.
The second and third layers are applied wet, but without streaking. Hold the can strictly perpendicular to the surface at a distance of 20-25 cm. Movements should be smooth, covering the already painted part of the previous pass by 50%. This ensures even distribution of the material.
⚠️ Attention: Do not try to paint over the defect with one thick layer! This is guaranteed to lead to drips that will take a long time and be difficult to remove by sanding.
Between layers it is necessary to pause for the solvent to evaporate (usually 10-15 minutes, read the instructions on the bottle). If you are working with metallics, after the base has dried (it will become matte), be sure to apply 2-3 layers of acrylic varnish for protection and depth of color.
To avoid a sharp boundary (step) between the old and new paint, use the technique of “blurring” the edges: apply the last layer of base a little wider than the previous one, and try not to bring the varnish to the boundaries of the repair area, creating a smooth transition.
Material compatibility chart and drying times
To achieve a professional result, it is important to maintain the compatibility of materials. Nitroenamel cannot be applied to acrylic primer or vice versa if they are not chemically compatible - this will lead to swelling of the coating. Below is an approximate drying time table for common types of car enamels at a temperature of +20°C.
| Material type | Drying time "from dust" | Interlayer dwell time | Complete polymerization |
|---|---|---|---|
| Acrylic enamel (2K) | 15-20 min | 20-30 min | 24 hours |
| Metallic base | 10-15 min | 15-20 min | Does not polymerize (requires varnish) |
| Acrylic varnish | 20-30 min | 30-40 min | 7-14 days |
| Primer-filler | 30-40 min | 60 min | 12 o'clock |
Please note that complete polymerization (strength gain) can take up to two weeks. During this period, it is better not to wash the car with aggressive chemicals or subject it to active mechanical stress. The varnish finally hardens and gains strength during this period.
Using infrared drying or placing the car in a warm chamber can shorten the initial drying time, but you still shouldn’t rush into polishing. Early polishing of fresh varnish can lead to clouding and the appearance of holograms.
Finishing and defect removal
After the varnish has completely dried, the surface may have some shagreen marks that differ from the factory one, or dust particles that have entered during the work process. Polishing is necessary to level the surface and obtain a perfect gloss. They start with abrasive polishing with a paste with a grit of P1500 or P2000, if the shagreen is strong, or immediately move on to medium-abrasive compounds.
Polishing This is done using a polishing machine with a soft wheel or manually if the repair area is very small. The main rule is not to rub the varnish through to the paint. The movements should be crosswise, without putting too much pressure on the tool. After abrasive, the surface is treated with finishing polish to remove micro-scratches and add depth.
If after painting there are minor defects, such as craters or small drips, they can be carefully removed with a scalpel (by cutting off the top) and polished. In the case of a serious color mismatch or shagreen that cannot be removed by polishing, the varnish and base layers will have to be removed with a solvent and the process must be started again.
⚠️ Attention: When polishing transitions, use only soft circles and finishing pastes so as not to matt the base varnish around the repair area.
The quality of the final polishing determines 50% of the success of the visual perception of the repair. Without polishing, even perfectly matched paint will look dull and rough.
Frequently asked questions (FAQ)
Is it possible to mix paint from different manufacturers in a spray can?
Strongly not recommended. The chemical composition of solvents and resins may vary between brands, which will result in paint curling, discoloration, or poor adhesion. Use products from the same line or leave the mixing to professionals.
How many coats of varnish should I apply to metallics?
Applying 2-3 layers of varnish is considered optimal. The first layer is a thin, binding layer. The second is the main one, wet, creating gloss. The third layer is applied if volume is needed or if the second layer lays unevenly. The main thing is to prevent drips.
Why can the paint in the can differ from the code on the body?
This occurs due to the natural fading of the old coating under the influence of the sun and reagents. New factory code paint will always be brighter. To perfectly match the tone, computer tinting is required taking into account the degree of fading or “transition” painting technology.
Do I need to prime a plastic bumper before painting?
Yes, definitely. For plastic (PP, ABS), a special adhesive primer is required, which ensures adhesion of the enamel to the flexible surface. Without it, the paint will begin to peel off over time as the bumper deforms.
How to store an open can of spray paint?
If there is any paint left in the can, turn it upside down and press the spray nozzle until clear gas comes out. This will clear the valve. It should be stored in a cool place, away from sources of fire, preferably at a temperature above 0°C, so that the structure of the emulsion is not disturbed.