Types of car paint: classification and selection features

Choosing the right paint and varnish material is a fundamental step in the body restoration process, which determines not only the visual appeal, but also the durability of the coating. The automotive chemical market today offers a wide range of solutions, from classic one-component formulations to complex multi-component systems with an overflow effect. Understanding the chemical basis of each type of paint can help you avoid costly renovation mistakes.

It is easy for an inexperienced car enthusiast to get confused in abbreviations like HS, MS or Base Coat, however, it is these parameters that dictate the drying technology and the necessary conditions for application. An error in choosing the compatibility of solvents or hardeners can lead to defects that will have to be eliminated by completely repainting the element. Therefore, before purchasing materials, you need to clearly understand what kind of result you want to get and what resources you have.

In this article we will analyze in detail the main types of paints, their technical characteristics and areas of application. We will consider both budget options for local repairs and professional systems used on factory conveyors. This will help you make an informed decision that fits your goals and budget.

Basic classification of automotive enamels

All automotive paints can be divided into two large groups according to the type of drying: one-component (1K) and two-component (2K). One-component materials dry solely due to the evaporation of the solvent, without requiring the addition of a hardener. Such compositions are often used for the restoration of discs, calipers or interior elements, where high chemical resistance is not required.

Unlike them, two-component systems consist of a base and hardener, which are mixed immediately before use. As a result of the chemical polymerization reaction, a durable film is formed that is resistant to gasoline, oil and mechanical stress. It is these materials that make up the lion's share of the body repair market.

Paints are also divided according to the type of binder. The most common are acrylic, alkyd and polyurethane compositions. Acrylic enamels are prized for their excellent gloss and ease of polishing, while alkyd (glyphthalic) paints are known for their high hiding power but long drying time. Polyurethane options are considered the standard of durability in modern body repair.

• 🎨 1K (Single component): They dry in air, do not require a hardener, and are less resistant to chemicals.
• 🧪 2K (Two-component): Requires mixing with a hardener and forms a super durable coating.
• 🛡️ Polyurethane: Maximum elasticity and chip resistance.

⚠️ Attention: Never attempt to apply varnish over one-component acrylic paint without first checking for compatibility and fully curing. Solvent from the varnish can "lift" the base coat, creating permanent "shagreen" or wrinkling of the finish.

It is important to understand that the choice between 1K and 2K depends on the area being painted. For external body elements exposed to aggressive environmental influences, the use of one-component materials without subsequent varnishing is considered a temporary solution. Two-component systems provide metal protection from corrosion for years to come.

Acrylic paints: quality standard and glossy shine

Acrylic car enamels are today the most popular choice for car painting due to their balance between price, quality and ease of application. The basis of these paints are polyacrylates, which provide a high degree of color saturation and excellent gloss even without the use of additional varnish (in the case of two-component acrylics).

The key feature of acrylic is its ability to polymerization. Unlike alkyd paints, which take a long time to dry and shrink, acrylic compositions form a hard film faster. However, they often require heat treatment or the addition of a special catalyst to achieve full strength. The pot life of the finished mixture is usually from 2 to 4 hours, after which the paint in the can begins to thicken and becomes unusable.

There are hard (HS - High Solid) and soft (MS - Medium Solid) acrylics. Solids contain more solids and less solvent, which allows you to apply a thicker layer without smudges and get a deep gloss after polishing. Soft acrylics are cheaper but require more layers to achieve a similar effect.

When working with acrylic paints, it is important to observe the temperature regime. The optimal temperature for drying is considered to be 20°C. At lower temperatures, the drying process slows down, which can result in dust getting onto the sticky surface. At high temperatures, paint may dry too quickly, causing an "orange peel" appearance.

Another important aspect is the compatibility of acrylic with various primers. Modern acrylic enamels adhere perfectly to epoxy and polyurethane primers, providing reliable adhesion. However, applying acrylic to old nitro-enamel coatings without an insulating layer is strictly prohibited due to the risk of dissolution of the lower layer.

Alkyd (Glypthal) enamels: traditions and features

Alkyd paints, often popularly referred to as “glyphthals,” have long been a standard in the auto industry. They are based on alkyd resins modified with vegetable oils. The main advantage of such enamels is their exceptional hiding power: One or two coats are often enough to completely cover color and surface imperfections.

However, alkyd paints have a significant drawback - a long drying period and lack of hardness in the first days after application. The paint film remains soft and susceptible to mechanical damage for several weeks. In addition, these materials are prone to oxidation when exposed to ultraviolet radiation, which leads to loss of gloss and surface chalking faster than acrylic counterparts.

In modern body repair, alkyd enamels are rarely used, mainly for restoring vintage cars or painting agricultural equipment, where aesthetics are secondary. They require mandatory application of varnish for protection, since they themselves do not have sufficient weather resistance for modern operating conditions.

• 🕰️ Long drying: Complete polymerization takes up to 30 days.
• 📉 Shrinkage: Prone to significant shrinkage when drying.
• 💰 Price: Usually cheaper than acrylic counterparts.

⚠️ Attention: Alkyd paints should not be applied over acrylic primers or putties without carefully checking the instructions. The solvents they contain may cause swelling of the underlying layers if they are not completely dry or are not chemically compatible.

If you do decide to use alkyd enamel, make sure that the painting area is well ventilated but free of dust. Due to the long “unstick” time, dust has a greater chance of settling on the surface, ruining the appearance. It is also worth considering that such coatings can be polished only after a full set of hardness, that is, no earlier than after a month.

Metallic, pearl and xerallic: spectacular pigments

When it comes to visual effects, colors like metallic, mother of pearl and more modern Xeralic. It is important to understand that these materials themselves are not independent coatings. These are the so-called “bases” (Base Coat), which require the application of a transparent varnish to protect and create depth of color.

Metallic contains crushed aluminum particles. Depending on the size and shape of these particles, the surface may shine like a mirror or have a soft, diffuse glow. The technique of applying metallics requires high skill: uneven spraying leads to a defect known as “bulling” (different shades at different viewing angles).

Mother of pearl uses mica coated with metal oxides. This material has the ability to refract light, creating a color shifting effect depending on the viewing angle. Pearlescent paints are usually applied in three stages: a colored base, a layer of pearlescent (transparent with pigment) and a varnish. This makes the painting process more labor-intensive and expensive.

What is the difference between Xeralic and regular metallic?

Xirallic is a pigment based on aluminum oxide of complex shape. Unlike the flat flakes of ordinary aluminum, Xeralic particles have a faceted structure. This creates a glow-from-within effect that is brighter and deeper than regular metallics and is often compared to the sparkle of precious stones.

The technology for applying such paints requires the use of spray guns with a certain torch and pressure. For metallics, the wet-on-wet method or with interlayer drying is often used so that the metal particles settle evenly. Violation of technology leads to the fact that the car may look spotty.

The varnish for such systems must be of high quality, with UV filters to prevent fading of the effective pigments. Cheap varnish can become cloudy over time, hiding all the beauty of the complex coating underneath.

Comparison table of paint characteristics

To simplify the choice of material, we provide a comparative analysis of the main parameters. This table will help you quickly navigate the advantages and disadvantages of each type of coating, depending on your tasks.

Parameter	Acrylic 2K	Alkyd (Glyphthal)	Metallic/Pearl	Nitroenamel (1K)
Chemical resistance	High	Average	Depends on the varnish	Low
Drying time	24 hours (full 7 days)	72 hours (full 30 days)	24 hours + varnish	1 hour
The need for varnish	Desirable (for gloss)	Required	Required	No
Covering power	Medium (2-3 layers)	High (1-2 layers)	Low (many layers)	Average
Difficulty of application	Average	High (due to viscosity)	High (risk of appleiness)	Low

As you can see from the table, 2K acrylic paints are the most universal solution for most body repair tasks. They combine acceptable drying time and good durability. Alkyd paints are becoming a thing of the past, giving way to more technologically advanced materials, although they find their niche in specific cases.

Nitro enamels, which were once the basis of the automotive industry, have now been almost completely replaced. Their main advantage - drying speed - is offset by extremely low durability and environmental hazards when applied. It makes sense to use them only when restoring factory-made cars of certain years of manufacture.

Application technology and surface preparation

Regardless of the type of paint chosen, 80% of painting success depends on the quality of surface preparation. Degreasing, sanding and proper priming are steps that cannot be ignored. Even the most expensive paint will not stick to a greasy or smooth surface.

The painting process usually looks like this: first, a primer-filler is applied, which evens out micro-irregularities. This is followed by a layer of insulating primer (if necessary), and only then paint. For two-component systems, it is critical to maintain the mixing proportions of the components. The use of measuring cups and scales is mandatory.

An important point is to create the right conditions in the spray booth. The temperature of the air and the surface of the part must be the same to avoid condensation. Humidity should not exceed 65%, otherwise dullness or “craters” may appear on the freshly painted surface.

⚠️ Attention: When working with two-component paints containing isocyanates, the use of a high-quality respirator with carbon filters is mandatory. The vapors from these substances are toxic and can cause serious respiratory problems even if inhaled briefly.

After applying the finishing coat, it is important to give the paint time to initially cure before use. Although the part may be dry to the touch after just an hour, the chemical processes inside the film continue for several days. During this period, it is not recommended to wash the car or expose it to aggressive chemicals.

Frequently asked questions (FAQ)

Can varnish be applied to one-component acrylic paint?

Technically this is possible, but it is risky. One-component paints (1K) dry by evaporation of the solvent and remain soft inside. Aggressive solvent from a two-component varnish can dissolve the base, creating defects. If you decide, you need to wait for complete polymerization (several weeks) or use special insulating primers.

How many coats of paint need to be applied for complete coverage?

Typically 2-3 coats of base color are required for a solid color and 3-4 thin coats for a metallic to avoid streaking. The amount depends on the hiding power of the particular enamel and the contrast of the color of the substrate. Always do a test spray on cardboard.

What is the difference between HS and MS varnish?

HS (High Solid) - varnish with a high solids. It gives a thicker layer, holds polish better and gives a deep gloss. MS (Medium Solid) - more liquid, cheaper, but gives a smaller layer and is less polished. For a car, HS is preferred.

Do I need to sand each coat of paint?

When painting “wet on wet”, sanding between base coats is not required if the drying intervals (flash-off) are observed. Only the primer is sanded before painting and, if necessary, the varnish is sanded before polishing if defects arise (specks of dust, smudges).