Sooner or later, every car owner is faced with the need to update the paintwork. Be it the consequences of a minor accident, a sun-bleached hood, or simply a desire to change the image of a loved one sedan, the question of choosing a material comes up sharply. Acrylic paint has been one of the most popular solutions for auto body repairs for several decades due to its availability and ease of application.
Unlike more difficult to work metallics or demanding conditions polyurethane enamels, acrylic forgives many mistakes of beginners. It dries quickly, holds color well and allows you to get a glossy shine even in garage conditions. However, in order for the result to please the eye for years, and not become covered with chips in a month, it is necessary to strictly follow the preparation and application technology.
In this article we will look at all the nuances of working with acrylic enamels. You'll find out why adhesion more important than the thickness of the layer, how to properly dilute the material and whether it is worth saving on varnish. The information will be useful both to those who plan to paint their car with their own hands, and to car owners who want to control the quality of work in the service.
Characteristics of acrylic car paint
Acrylic enamels belong to the group of materials that dry due to the evaporation of the solvent and subsequent polymerization. The basis of such paints is acrylic resins, which after drying form a durable, elastic film. The main feature is the high drying speed, which significantly speeds up the repair process compared to alkyd analogues.
Modern acrylic compositions have excellent hiding power, allowing you to cover the color of the old coating in 2-3 layers. They are resistant to ultraviolet radiation, do not turn yellow over time and retain color saturation. In addition, acrylic has good elasticity, which is critical for body parts subject to vibration and thermal expansion.
When purchasing paint, pay attention to the HS (High Solid) marking - these are highly concentrated materials that shrink less when drying and require fewer layers.
However, the material also has its limitations. Acrylic paints are less resistant to mechanical damage, such as scratches from branches or high-pressure washing, compared to two-component polyurethanes. Therefore, applying a protective varnish over the base is a mandatory step for the durability of the coating.
Necessary tools and room preparation
The quality of painting depends 80% on preparation. To work, you will need not only the paint itself, but also a specialized tool. It is strictly forbidden to paint in a living room or outdoors: dust and insects will spoil the gloss, and drafts will disrupt the polymerization process.
The ideal option is a spray booth, but for garage repairs a clean, well-lit room with an air temperature of +20°C is suitable. Be sure to wet clean the floor and walls to remove dust. Drafts are not allowed, but ventilation must ensure the removal of solvent vapors.
- 🎨 Spray gun (spray gun) with a nozzle of 1.3–1.5 mm - for applying base and varnish.
- 🔧 Compressor with receiver - must provide stable air pressure.
- 🛡️ Personal protective equipment - respirator with carbon filters, gloves, suit.
- 🧼 Degreaser and anti-silicone - for final cleaning of the surface.
Pay special attention to preparing the spray gun. Before pouring paint, make sure the needle and nozzle are clean and the spray pattern is adjusted. Using cheap Chinese spray guns often leads to spitting and uneven application, so it is better to choose a proven tool with adjustable material flow.
Technology for preparing the body for painting
Surface preparation is the most labor-intensive stage, which directly determines how long the new paint will last. If you apply enamel over grease, rust, or poorly sanded soil, it will begin to peel or bubble after a short time.
The first step is to make matting old covering. If you are painting the entire part, the old paint must be sanded with P400-P500 abrasive. This will create the risk necessary for mechanical adhesion of the new material. A glossy surface cannot be painted “for gloss” - the material will simply run off or lie unevenly.
⚠️ Attention: Never use gasoline, kerosene or aggressive solvents (acetone, 646) for degreasing at the final preparation stage. They can soften old soil or leave a greasy film, which will lead to defects. Use only specialized
antisilicone.
After sanding, the surface is thoroughly blown with compressed air and wiped with a cloth moistened with a degreaser. The movements should be progressive, without reciprocating actions, so as not to smear the contaminants. After this, touching the surface with gloved hands is strictly prohibited.
☑️ Preparation checklist
Diluting paint and setting up the spray gun
Acrylic paint is sold as a ready-made concentrate or requires mixing with a solvent. The proportions are usually indicated on the can by the manufacturer and may vary. For standard conditions (temperature +20°C) a ratio of 10:1 (10 parts paint to 1 part solvent) is often used, but the exact data must be consulted in the technical data sheet (TDS).
The thinner is selected depending on the room temperature. For hot weather, use a “slow” solvent so that the paint does not have time to dry on the fly, forming shagreen. In a cold room, on the contrary, a “fast” solvent is needed to accelerate evaporation.
Recommended pressure at the outlet of the spray gun: 2.0 - 2.5 atm.Setting the spray pattern is a critical point. Before painting, do a test pass on cardboard or an old piece. The torch should be smooth, without breaks or thickening at the edges. If the paint streaks or spits, check the viscosity of the mixture and the air pressure.
The secret of the perfect torch
If the torch is shaped like a figure eight or breaks in the middle, the nozzle is most likely clogged or the atomizer horn is damaged. Disassemble and rinse the spray gun head in solvent with ultrasound or a brush.
Acrylic materials begin to thicken within 2-3 hours after mixing with a hardener or solvent. Prepare as much mixture as you can produce in one work session.
Acrylic enamel application process
Applying paint requires skill and calm. Hold the spray gun perpendicular to the surface at a distance of 15-20 cm. Movements should be smooth, parallel to the plane of the part. The speed of moving the tool should be uniform: too fast - there will be little paint (not painted), too slow - drips.
The first layer is applied thin, the so-called “dust layer”. Its purpose is to create a base for adhesion, not to cover up the color. Don't try to paint everything the first time. Allow the first coat to dry (usually 10-15 minutes, depending on temperature and type of solvent) before applying the second.
- 🌫️ The second layer is the main one, applied more intensely, covering 50-70% of the surface with the previous pass.
- ✨ The third layer (control) - allows you to even out the shade and achieve gloss if the paint is one-component.
- ⏱️ Interlayer exposure - strictly according to the instructions, do not overexpose the time, otherwise the interlayer adhesion will be broken.
Pay special attention to edges and difficult terrain. On sharp edges, paint tends to shrink, leaving a thin layer that will quickly rub off. These places can be carefully covered with additional light spraying, but without fanaticism, so as not to form sagging.
Drying, polishing and parameter table
After applying the finishing layer, the drying process begins. Acrylic paints dry “touch” after 20-30 minutes, but they gain full chemical and mechanical strength in 7-14 days. During this period, it is better not to wash the car with chemicals or subject it to heavy loads.
If after drying shagreen (orange peel) or dust particles are found, the defects are eliminated by polishing. You can use abrasive pastes only after complete polymerization of the varnish or paint, otherwise you can wipe the coating down to the metal.
| Parameter | Value/Time | Terms |
|---|---|---|
| Touch dry | 20-30 minutes | +20°C, humidity 60% |
| Interlayer drying | 10-15 minutes | Depends on solvent |
| Complete polymerization | 7-14 days | Natural drying |
| Drying temperature | 20°C - 60°C | No sudden changes |
Full chemical resistance of the acrylic coating is achieved only two weeks after painting. Until this time, washing with shampoo and active use are undesirable.
To speed up the process, you can use infrared dryers, but you need to heat the part evenly, starting from the edges, to avoid boiling of the solvent under the paint crust. Sudden heating may cause bubbles and craters to appear.
Frequent mistakes and defects when painting
Even experienced craftsmen are not immune from defects, but knowing the reasons for their occurrence helps to minimize risks. The most common problem is drips. They occur due to the spray gun being too close, the hand moving slowly, or the paint being too thin.
Shagreen (coarse grain) often appears when working in a too hot room or when using a fast solvent. The paint does not have time to spread and hardens in the form of tubercles. The cause may also be insufficient air pressure or a large distance to the part.
⚠️ Attention: If you notice dullness (blue discoloration) on the glossy finish immediately after painting, this is a sign of high humidity in the room or water getting into the compressor. You cannot dry such a part with a hairdryer - the moisture will be driven deeper. It is necessary to allow the moisture to completely evaporate and repolish the surface.
Craters (fisheyes) are small, round depressions caused by silicone or oil on the surface. It is difficult to deal with them; often only complete repainting using anti-silicone additives helps. Prevention is more important than treatment here.
Comparison of acrylic with other types of coatings
When choosing a material, many compare acrylic with metallized enamels or powder coatings. Acrylic wins in price and ease of local repair. A scratch on acrylic can be polished or tinted with a brush, which cannot be done efficiently on metallic without transferring to the adjacent part.
However, in terms of color depth and effects (mother of pearl, chameleon), acrylic is inferior to more complex systems. For budget cars, commercial vehicles or parts that do not require perfect gloss (internal sills, underbody), acrylic is the best choice.
In the long term, acrylic may require more frequent polishing to restore shine as it is less hard than two-part varnishes. But with proper care (regular washing, use of wax), the coating lasts 5-7 years without loss of decorative properties.
The Compatibility Myth
Many people believe that acrylic cannot be varnished. This is not true. The varnish fits perfectly on an acrylic base (Base Coat) if the technology is followed. Confusion arises with one-component acrylic enamels, which dry by evaporation and do not require varnish, but do not provide as much protection.
Conclusion
Painting your car with acrylic is an affordable way to make your car look attractive again. The material forgives many mistakes, dries quickly and is inexpensive. The main thing is not to skimp on surface preparation and high-quality solvents, since they are the ones who determine the final result.
Compliance with the temperature regime, cleanliness in the work area and the correct choice of tools will allow you to obtain a result that is not much inferior to the factory one. Remember that patience and accuracy in this matter are more important than speed.
Can I paint with acrylic over old paint?
Yes, you can, if the old coating is durable, does not peel off and does not have swelling. Be sure to mat the surface with P400-P500 abrasive and degrease it. If the old paint is chalking or crumbling, it must be completely removed.
How long does acrylic paint dry before polishing?
Although the paint becomes hard after a few hours, it is recommended to start abrasive polishing no earlier than 24 hours, and ideally after 3-7 days, to avoid the risk of damaging the layer that has not yet fully polymerized.
Do you need varnish for acrylic paint?
If you use one-component acrylic (1K), varnish is not necessary and may even be harmful. If it is a two-component base (2K Base Coat), then varnish is required to protect the color and add gloss. Always read the instructions on the can.
How to dilute thickened acrylic paint?
Use only the thinner recommended by the manufacturer (usually 647, 650 or brand thinner). Do not add gasoline, acetone or other aggressive liquids - they can curdle the resin.