Restoring a car's paintwork is a process that scares many owners, although local painting is accessible even to a beginner. Small defects, such as gravel chips or deep scratches, will lead to metal corrosion over time if not corrected promptly. Done correctly local painting not only restores the aesthetic appearance, but also protects the body from rust, extending the life of the car.
Before starting work, it is necessary to objectively assess the extent of the damage. If rust has already started to “bubble” under the paint or a large area of the body is damaged, professional repairs may be required in the chamber. However, for pinpoint defects the size of a coin or scratches that do not reach the plastic of the bumper, do-it-yourself restoration will be economically justified. The main thing here is not to rush and carefully follow the surface preparation technology.
The quality of the final result directly depends on the cleanliness of the room and the materials used. Dust settling on fresh paint or an incorrectly selected solvent can ruin the entire job. In this article we will analyze a step-by-step algorithm of actions that will allow you to achieve factory-quality coating in a regular garage.
Damage assessment and selection of materials
The first step is always a detailed inspection of the body in good lighting. It is necessary to determine the depth of the damage: whether only the varnish is affected, whether the base (color) itself is damaged, or whether the scratch has reached the primer and metal. To work, you will need the exact color code for your car, which is usually located on the driver's door pillar or in the engine compartment. It is best to select paint in a specialized color laboratory, where a computer will mix the components to perfectly match the tone.
⚠️ Attention: Even with perfect color selection, the new paint may differ from the old coating that has faded in the sun. Before applying to a visible part, be sure to do a test paint on a metal plate or hidden area of the body.
To perform the work efficiently, you will need a specific set of tools and consumables. You should not skimp on abrasive materials and degreasers, since the adhesion (cohesion) of the layers depends on them. The basic kit includes a polisher or drill with an attachment, a set of sandpaper of different grits, a degreaser, an anti-corrosion primer (if there is exposed metal), base enamel and automotive clear coat.
Special attention should be paid to the choice of paint type. Modern cars are most often painted using the “base enamel + varnish” system, while older models or some budget options may use acrylic enamels that do not require varnish. You can determine the type of coating by wiping the hidden area with a white rag soaked in polish: if the color remains on the rag, it means there is no layer of varnish on top, and the painting technology will be different.
Preparation of the workplace and
The success of an event depends 80% on preparation. Painting in a dusty garage or outdoors in windy weather is doomed to failure, since any grain of sand that gets onto the fresh varnish will become a noticeable defect. The ideal room should be well lit, have a temperature of +18 to +22 degrees Celsius and minimal air circulation to avoid dust. Before starting work, be sure to wet clean the floor and walls to remove dust.
A list of necessary equipment should be compiled in advance so as not to interrupt the process. You will need:
- 🧤 Personal protective equipment: respirator with carbon filter, rubber gloves, safety glasses.
- 🔧 Tools for cleaning: sander (or hand block), sandpaper P320, P600, P1000, P2000.
- 🧴 Chemistry: degreaser (anti-silicone), polishing paste, primer in aerosol or spray.
- 🎨 Spray gun (if the paint is not in cans), compressor, masking tape and covering film.
It is important to check the serviceability of the compressor and spray gun. The air pressure should be stable, usually in the range of 2-3 atmospheres, depending on the paint manufacturer's recommendations. If you are using ready-made aerosol cans, make sure that the ball inside moves freely, which indicates the normal consistency of the contents. To mix ingredients, use measuring cups with the proportions indicated on the jar.
Use a tack cloth immediately before painting - it effectively removes the smallest lint and dust that the eye cannot see, but which will spoil the gloss.
Stripping and priming technology
The surface preparation process requires patience and accuracy. First, the damaged area and the area around it are thoroughly washed and degreased. Then the edges of the chip or scratch are mechanically cleaned. Your task is to make the transition from intact paint to damage as smooth as possible, so that no steps are visible after painting. For this, sandpaper with grit P320-P600 is used.
If there is exposed metal in the defect, it must be treated with a rust converter (if there are oxides) and coated with acid or epoxy primer. This layer will prevent further corrosion. The primer is applied in thin layers with interlayer drying specified by the manufacturer. After drying, the primer is sanded with fine sandpaper P800-P1000 until perfectly smooth.
Sanding sequence: P320 (removing old paint) -> P600 (smoothing) -> P1000 (preparing for primer) -> P2000 (polishing transitions)After priming, the surface is degreased again. It is important not to touch the prepared surface with your hands, as skin oil will impair the adhesion of the paint. At this stage, you can use masking tape and film to cover adjacent body parts that cannot be painted. The adhesive tape must be glued so that it does not extend into the area where the paint is being sprayed, otherwise, after removing it, a sharp border will remain.
☑️ Surface preparation checklist
Process of applying paint and varnish
Applying base enamel is the most critical stage. The paint must be applied in thin layers, giving each layer time for the solvent to evaporate (usually 10-15 minutes). The first layer may be translucent (“foggy”), this is normal. The second and third layers are applied more richly, covering the primer and the old color. It is important to hold the spray gun or can perpendicular to the surface at a distance of 15-20 cm.
There should be no pauses between layers longer than the specified time, otherwise interlayer adhesion may be disrupted. If the paint starts to dry too quickly (for example, in hot weather), you can add a drying retardant. After the base enamel has completely covered the surface and is even in tone, you need to let it dry to a matte state (usually 20-30 minutes) before applying varnish.
| Parameter | Basecoat | Acrylic varnish (Clearcoat) | Primer |
|---|---|---|---|
| Number of layers | 2-3 layers | 2 layers | 1-2 layers |
| Drying time (20°C) | 15-20 min between coats | 10-15 min between coats | 30-60 min between coats |
| Finish state | Matte | Glossy | Matte/Semi-matte |
Varnishing is done in a similar way: two thin but wet layers. The varnish should spread to form a glossy “orange peel” that will then buff off. Do not try to pour everything at once in one thick layer - this will lead to drips that are very difficult to remove. If a drip does form, let the varnish dry completely (preferably a day), then carefully cut it off with a blade and sand it.
What to do if the paint comes out in spots (apples)?
Applespotting often occurs when painting with metallic paints due to uneven distribution of aluminum powder. To avoid this, the final base layer (the "fog layer") is applied from a greater distance and with more solvent. This helps the powder set evenly. If stains already exist, they can only be removed by completely repainting the element or by thorough polishing after varnishing if the defect is not deep.
Polishing and removing defects
Immediately after painting, the surface may not look ideal: there may be shagreen (unevenness of the varnish), dust or small debris. Polishing allows you to remove these defects and give the body a mirror shine. You can start polishing only after the varnish has completely polymerized, which takes from several days to weeks, depending on the type of varnish. However, there are “hard-to-dry” varnishes that allow polishing after just 24 hours.
The polishing process is divided into two stages: restorative and finishing. First, an abrasive paste and a hard wheel (usually orange or white) is used to remove the shagreen. Movements should be smooth, without strong pressure, so as not to rub the varnish into the paint. After obtaining a uniform matte shine, proceed to the finishing paste and soft circle to remove holograms.
⚠️ Attention: Be extremely careful when polishing the edges and corners of the body. In these places the varnish layer is thinnest, and it is very easy to rub it down to the base enamel, which will require a complete repainting of the part.
To achieve the best result, use a polishing machine with variable speed control. Start at low speed (about 1000 rpm) to distribute the paste, then increase to 2000-2500 rpm to work. After polishing, the surface must be washed and coated with protective wax or ceramic compound to consolidate the effect.
The quality of polishing determines 50% of the visual perception of painting. Even perfectly applied paint will look cheap without proper finishing treatment with abrasive pastes.
Common mistakes and how to avoid them
Beginners often make a number of mistakes that ruin all their efforts. One of the most common is insufficient defatting. This leads to the paint being applied with defects (“craters”) or completely peeling off after some time. Always use a high-quality degreaser and two wipes: one to apply, the other dry to remove any residue.
Another common problem is incorrect paint viscosity. If the paint is too thick, it will not spread, leaving shagreen. If it is too liquid, drips are guaranteed. Use a viscometer for an accurate measurement, or strictly follow the instructions on the can for the amount of solvent you add. The temperature in the room is also critical: in the cold, the paint dries longer and can become dull; in the heat, it dries instantly, without having time to spread.
Ignoring the “transition” technology when painting locally leads to the fact that the border between new and old paint becomes noticeable. To make the transition invisible, a new layer of paint should overlap the old one, shading the boundaries with a solvent. This requires skill, so for large areas it is better to practice on an unnecessary part.
Why can paint peel off after a month?
Most often, the reason lies in moisture or oil from the compressor getting into the paint, or in applying paint to poorly dried soil. It is also possible to use incompatible materials (for example, applying acrylic paint to nitro primer without an insulating layer).
Is it possible to tint a car with regular spray enamel?
Yes, for very small chips this is acceptable, but for noticeable areas the result will differ from the factory one. Car enamels from spray cans often have a different shade and less durability than professional code-matched paint. In addition, it is difficult to control the pressure and spray pattern.
How long does it take for paint to dry on a car?
The base enamel dries “touch” in 15-30 minutes, but complete polymerization takes several days. The varnish dries in 24 hours at room temperature, but will gain hardness within 2-3 weeks. You can wash your car with aggressive chemicals no earlier than after a month.
Do I need to remove the part from the car for painting?
For chips and scratches, removal of the part is not required. If the damage is located at the junction of parts or requires complex polishing of the transitions, removing the element (door, wing) can facilitate access and provide a better result.
How to remove paint streaks if they have already dried?
The dried drip should be carefully cut off with a razor blade flush with the surface, then sanded with P2000 sandpaper and water until the step disappears. After this, the sanding area is polished with an abrasive paste to restore gloss.