Applying the base coat is one of the most critical stages of painting a car, on which not only the appearance, but also the durability of the entire paintwork depends. Even minor mistakes at this stage can lead to color subsidence, "orange peel" effect or premature peeling of varnish. In this article we will look at professional base application techniques, features of working with different types of paints and critical nuances that 80% of beginners ignore.
Modern base enamels are divided into three main types: acrylic, metallics and mother-of-pearl. Each requires a specific approach, from dilution to spray technique. For example, metallics are sensitive to pressure in the spray gun, and pearlescent paints can “run away” if applied at the wrong angle. We will tell you how to avoid typical problems and achieve deep, rich color no defects.
1. Choosing a base: acrylic, metallic or mother-of-pearl?
Not only the final appearance of the car, but also the complexity of the work depends on the type of base enamel. Acrylic bases are the easiest to apply, but they do not give such a deep effect as metallics or pearlescents. The latter require ideal surface preparation, since any unevenness will be enhanced by light refraction.
When choosing, pay attention to:
- 🔹 Soil compatibility: some bases require special insulating primers (for example, for water-soluble paints).
- 🔹 Mixing system: Metallics are often sold as
base + hardener + thinner, and acrylic ones can be ready for use. - 🔹 Covering power: Pearlescent paints may require 3-4 coats for an even color, while acrylics usually require 2 coats.
Professionals often use databases from PPG, Sikkens or Mobihel — these brands offer wide palettes and stable quality. However, domestic analogues are also suitable for budget repairs, for example, Vika or Duxone, if you choose the right thinner.
2. Body preparation: why 90% of defects occur at this stage
Even the most expensive base will lie unevenly if the surface is not properly prepared. Main stages:
- Cleaning: removing silicones, wax and grease stains using degreaser (for example, App W900).
- Ground grinding: use abrasive
P800-P1200for a matte surface. For metallics and pearlescents it is better to takeP1000-P1500- this will reduce the risk of pigment subsidence. - Blowing with compressed air: Dust particles left behind after sanding can ruin the result.
A critical mistake many newbies make is skipping anti-silicone treatment. Silicones contained in polishes or even household dust lead to cratering (small funnels) in the base. To avoid this, after degreasing, wipe the surface with a cloth soaked in white spirit, and let it dry completely.
Remove all stickers and moldings | Matte the ground with P1000+ abrasive | Degrease the surface with anti-silicone | Blow with compressed air (pressure 4-6 bar) | Check the lighting (no glare from lamps)-->
3. Equipment settings: pressure, nozzle and distance
The parameters of the spray gun directly affect the quality of the coating. Optimal settings:
| Base type | Pressure (bar) | Nozzle size (mm) | Distance to surface (cm) | Travel speed |
|---|---|---|---|---|
| Acrylic | 2.0–2.5 | 1.3–1.4 | 15–20 | 40–50 cm/s |
| Metallic | 2.2–2.8 | 1.2–1.3 | 20–25 | 30–40 cm/s |
| Mother of pearl | 2.5–3.0 | 1.1–1.2 | 25–30 | 20–30 cm/s |
Critical for metallics and pearls uniform spray. If you hold the gun too close, the paint will lay down in a thick layer and may “bump” when drying. If it's too far away, the pigment won't spread evenly, and spots will appear. stripes. Optimal spray angle - 90° to the surface, deviations more 15° will lead to uneven coverage.
Before starting work, check the viscosity of the paint with a viscometer. For most bases, the optimal expiration time is 18–22 seconds at 20°C.
4. Application technique: layers, overlapping and drying
The base is applied in 2–4 layers depending on type and color. General rule: each subsequent layer should overlap the previous one by 50–70%. For metallics and pearls, it is important to keep the gun in the same direction - usually "criss-cross" (the first layer is horizontal, the second is vertical).
Typical application patterns:
- 🔸 Acrylic bases: 2 layers with interlayer drying for 5–10 minutes.
- 🔸 Metallicas: 2-3 layers, the last layer is applied “wet on wet” to even out the pigment.
- 🔸 Mother of pearl: 3-4 layers with increased drying between layers (10-15 minutes), as the pigment settles more slowly.
The temperature and humidity in the spray booth must be stable: 20–25°C and 50–70% accordingly. At a lower temperature, the paint will take longer to dry, and at a higher temperature it may crack. Pearlescent bases are especially sensitive to drafts: even a weak air flow can blow away the pigment, creating an uneven color.
What to do if the base is uneven?
If you notice streaking or "spotting" after application, do not try to correct it with an additional coat - this will only make the problem worse. Allow the base to dry completely (24 hours), then sand the defective area with a P1500-P2000 abrasive and reapply 1-2 coats. For metallics and pearls, it may be necessary to completely remove the old base down to the primer.
5. Common mistakes and how to avoid them
Even experienced painters sometimes encounter defects. Here are the most common problems and their causes:
⚠️ Attention: If, after applying the base, small craters appear (like from a shotgun), most likely the surface was poorly degreased. In this case, it is necessary to remove the defective layer and repeat the preparation using anti-silicone degreaser.
"Orange Peel" arises due to:
- 🔘 The pressure in the spray gun is too high (more than 3 bar).
- 🔘 Rapid evaporation of the solvent (often happens at high temperatures in the chamber).
- 🔘 Incorrect paint viscosity (too thick).
Color Drawdown (when the base looks dull after varnishing) is typical for metallics and pearls. Reasons:
- 🔘 Insufficient number of layers (less than 3 for mother of pearl).
- 🔘 Inter-layer drying is too long (the pigment settles unevenly).
- 🔘 Using unsuitable varnish (for example, HS varnish instead of MS-varnish for mother of pearl).
For metallics and pearlescents, be sure to use a “binding” layer of varnish - the first layer of varnish is applied with an increased amount of thinner (up to 20%) to “fix” the base pigment.
6. Drying and preparation for varnishing
After applying the last layer of base, it is necessary to wait technological pause before varnishing. The time depends on the type of paint and conditions:
- 🕒 Acrylic bases: 15–30 minutes at
20°C. - 🕒 Metallicas: 30–60 minutes (longer for dark colors).
- 🕒 Mother of pearl: 1-2 hours (pigment needs time to settle).
Before varnishing, be sure to check the base for unstuck: Lightly touch the paint with your finger in an inconspicuous place. If it does not stick, you can apply varnish. If the base has “lifted” (it has become sticky), this means that:
- 🔴 Incorrect thinner used (too slow).
- 🔴 The chamber has high humidity (more than 70%).
- 🔴 The base layer is too thick (it should have been applied thinner).
To speed up drying you can use IR heaters, but it is important to avoid local overheating - this can lead to bubbling paints Optimal distance to the heater: 1–1.5 meters.
7. Features of working with different colors
Some colors require a special approach:
- 🟡 Yellow and orange: often have low coverage and may require 3-4 coats.
- ⚫ Black metallics: sensitive to layer thickness - may appear when repainted stripes.
- 🔴 Red mother of pearl: prone to pink shade if the lighting in the camera is incorrect.
- 🟢 Green metallics: can give bluish tint, if applied too thinly.
For dark colors (black, dark blue) critical soil quality - any irregularities will be visible after varnishing. Light colors (white, silver) are more forgiving, but require perfect cleanliness in the camera, since even microscopic dust is visible on them.
When working with pearlescent paints, use gray soil instead of the standard white or black. This will help avoid unwanted tints in the final color.
8. Varnishing: how to fix the result
Varnish is applied over the base to protect and add gloss. Important:
- 🔹 Use varnish of the same brand as the base (for example, PPG D8115 for bases PPG).
- 🔹 Apply 2-3 layers with inter-layer drying for 5-10 minutes.
- 🔹 For metallics, make the first layer of varnish semi-dry (“fog”) so as not to disturb the orientation of the pigment.
After varnishing, the car must be dried for at least 24 hours at room temperature or 2–3 hours in the drying chamber at 60°C. Complete polymerization of the varnish takes up to 7 days — during this period, you cannot wash the car with aggressive shampoos or polish it.
⚠️ Attention: If after varnishing there are cloudy spots, this is a sign of incompatibility between the varnish and the base or drying too quickly. In this case, a complete repolishing or repainting of the part will be required.
Frequently Asked Questions
Is it possible to apply base without primer?
No, soil is required. It ensures adhesion and evens out micro-irregularities. The exception is local repairs, when the base is applied to old paint, but in this case the surface must be matted with abrasive P1200–P1500.
How many base layers are needed for mother of pearl?
Usually 3-4 layers. The first layer is “fog” (light spray), then 2-3 full layers with drying between layers for 10-15 minutes. The last layer should be the most uniform.
Why did the base become dull after varnishing?
It's called color subsidence. Reasons: too thin base layers, long drying time between layers or unsuitable varnish. The solution is to repaint the part in accordance with the technology.
Is it possible to paint metallic paint in a garage without a spray booth?
Technically it is possible, but the risk of defects increases significantly. It is difficult to control dust, temperature and humidity in a garage. If painting in the garage, use dust screen made of polyethylene and heater to stabilize the temperature.
How to avoid streaks on metallics?
Streaking (or "tiger effect") is caused by uneven spraying. To avoid them:
- Hold the gun at the same distance (20–25 cm).
- Move the gun at the same speed.
- Use antistatic gun or ground the part.