The question of the need to use additional liquids for paints (varnishes) often puzzles beginners and motorists who decided to repair the body. Acrylic paintsThe nutrients used in auto repair are complex chemical compositions where the balance of components plays a crucial role in the final result. Many people mistakenly believe that if the can of paint is open, the contents are immediately ready for application, ignoring the physicochemical properties of the material.
In fact, the answer to the question of whether a diluent is needed depends on many factors: environmental conditions, method of application and the state of the material itself. In professional car painting acrylic almost always require adjustment of viscosity to ensure proper spreading and the absence of defects on the surface of the body. Ignoring this stage can lead to shaking, leaking, or even detachment of the coating in the future.
Understanding nature acrylic binder This prevents fatal mistakes in painting. Unlike oil compounds, acrylic polymerizes under the influence of air and temperature, and the addition of incorrect solvents can completely stop this process or, conversely, accelerate it so that the paint dries even in the spray gun. It is therefore important to distinguish clearly when supplementation is needed and when it will only cause harm.
Chemical composition and role of solvents in acrylic
To understand why a diluent is needed at all, it is necessary to consider the structure of acrylic paint. This is a dispersion of pigments and fillers in an aqueous or organic medium containing polymer. In the automotive industry, two-component systems are most commonly used, where a hardener is added to the base, but even these require fine tuning of viscosity. The solvent in this case acts not just as a liquid for liquefaction, but as a regulator of the evaporation rate.
Organic solventsThe nutrients that make up the specialized diluents affect how quickly the volatile fraction will evaporate. If this process goes too quickly, the paint will not have time to spread, forming a rough shaver. If the evaporation is too slow, there will be stains, especially on the vertical surfaces of the body. It is critical to use only those diluents that are recommended by the manufacturer of a particular paint system.
There is a misconception that water can replace a special solvent for acrylic. Although there are water-soluble acrylics, they are rarely used in auto repair because of their low performance compared to solvative systems. Attempts to dilute car acrylic enamel with water will lead to the stratification of components and loss of adhesion. Chemical compatibility It is the foundation of a long-lasting coating.
⚠️ Note: Never use acetone or aggressive solvents (e.g., 646 in its pure form for some systems) without compatibility testing, as they can cause acrylic resins to clot, turning the paint into an unusable mass.
What is happening at the molecular level?
When the correct diluent is added, the polymer molecules get more space for movement, which reduces viscosity. When the solvent evaporates, the polymer chains approach and form a strong grid.
When a diluent is really needed
Determine the need to add a diluent can be several key features related to working conditions and the condition of the paint. First of all, it is the temperature in the paint chamber or garage. At low temperatures, the viscosity of the material naturally increases, making it impossible to spray high-quality through the spray duct. In such cases viscosity adjustment It becomes a mandatory procedure.
Also, a diluent is needed if you use paint that has stood for a long time and thickened, but has not yet lost its properties. Even fresh material is often supplied in a consistency that requires fine-tuning for a specific tool. For example, for pneumatic spray guns with a diameter of dusa 1.3 mm requires a more liquid paint than for the roller or brush, although in auto repair the latter are used extremely rarely.
Another important aspect is the application method. If you're working with metallic (metallic), the viscosity control is critical for the proper distribution of aluminum powder. Too thick paint will not give the desired effect, and too liquid will lead to stripes. For base layers, special diluents are often used that evaporate quickly to reduce drying time between layers.
- 🌡️ The room temperature is below.
+20°CA faster "dilluent" is required. - 🔫 Use of a spray gun with a small duose (less than a
1.4 mm) requires a reduction in viscosity. - ⏳ Long-term storage of paint led to its natural thickening.
- 💎 Work with spectacular pigments (pearl, metallic) to control the orientation of particles.
Types of diluents: how to choose the right one
Choosing a diluent is not just buying the first can you see that says "solvent." In professional coloring and painting of cars, there is a gradation according to the evaporation rate, which directly depends on the ambient temperature. Fast diluents They are designed to work in cold conditions, as they contribute to the accelerated drying of the layer, preventing influxes.
For hot weather or working in a heated chamber at high temperatures, you need to slow-motion. They allow the paint to stay in liquid state longer, providing perfect spreading and a glossy finish. If you use a quick solvent in the heat, the paint will "boil" on the surface, forming matte spots and a shavern, which will have to be sanded. Medium diluents are considered universal and suitable for standard conditions +20..+25°C.
It is also important to pay attention to the chemical basis. For acrylic enamels, varnishes and soils, solvents based on esters, ketones and aromatic hydrocarbons are usually used. It is important that solvent It was the same type of resin. Use of universal solvents of type 647 or 650 It is permissible for washing the tool, but for breeding high-quality paint it is better to take original products of the same brand.
| Type of diluent | Temperature regime | Evaporation rate | Application |
|---|---|---|---|
| Fast (Fast) | before +15°C |
Tall. | Cold rooms, local repairs |
| Normal medium. | +15..+25°C |
Medium | Standard Conditions, Universal Use |
| Slow (Slow) | higher +25°C |
Low. | Hot weather, large areas of painting |
| Specialist | Depends on TK | Different. | For pearls, matte varnishes, textures |
When buying a diluent, always take it with a margin of 10-15% of the calculated volume, since part of the liquid will inevitably go to wash the spray gun between the layers or change color.
Mixing and proportions technology
The process of preparing the working mixture requires accuracy and compliance with the sequence of actions. Disruption of proportions can lead to the hardener It will not react properly and the coating will remain soft or brittle. Usually, the exact mixing proportions are indicated on the paint can or on the technical card (TDS), for example, 2:1:10% (Two paint parts, one hardener, 10% diluent)
First, the base is poured into the container, then a hardener is added, and only after careful mixing is a diluent introduced. This rule is important because adding a diluent to a concentrated hardener can cause an unwanted chemical reaction. Stirring should be intense to lift all pigments from the bottom, especially in heavy areas. metallized paints.
To measure viscosity, professionals use a viscometer - a funnel with a calibrated hole. The time of the jet leak indicates whether the mixture is ready to work. If you do not have a viscometer, you can use the method "by eye", but it requires experience: the mixture should flow from the stirrer with a uniform trickle, breaking off about a centimeter from the edge, and not drip and do not flow.
☑️ The procedure for mixing paint
Usually, acrylic compounds with a hardener retain properties from 2 to 4 hours. The diluent can slightly extend or shorten this time depending on its evaporation rate, but you should not count on this.
⚠️ Warning: Never pour residues of mixed hardener paint back into a shared jar! This will lead to damage to the entire volume of the material due to the polymerization reaction that has begun.
How dangerous is improper dilution
Ignoring dilution rules or using inappropriate liquids leads to a whole bunch of defects, the elimination of which will require a complete repainting of the part. One of the most common effects is shagrain (orange peel) when the surface becomes bumpy. It happens when paint-viscosity It is too high and does not have time to spread until the time of drying.
The other extreme is the subductions that occur when excessive dilution or the use of too "slow" solvent in a cold room. The paint loses its thixotropicity and flows down under the influence of gravity. In addition, an improper solvent can cause varnish clouding (the “whitening effect”), especially at high humidity, when moisture condenses into a layer of paint.
The most serious defect is the loss of adhesion. If solvent The liquid is insufficient, the polymer chains do not adhere to the surface or the previous layer properly. Over time, such a coating will begin to peel off layers or swell with bubbles. Restore such a detail can only be a complete removal of the coating to the ground or metal.
- 🍊 Shagrens and irregularities due to too thick mixture.
- 💧 Sweating and flowing with excess solvent.
- 🌫️ The loss and loss of the stain at the finish.
- 🧱 Peeling and swelling due to poor adhesion.
A properly selected diluent provides not only ease of application, but also ensures that the physicochemical properties of the coating (hardness, elasticity, gloss) will correspond to the manufacturer's stated requirements.
Recovery and storage of materials
If the acrylic paint thickened in the jar, but the expiration date has not yet expired, you can try to restore it. To do this, you need to carefully add a fresh diluent of the same brand and mix thoroughly. However, it is worth understanding that if the paint has already begun the processes of gel formation (it turned into jelly), then no additives will not help - the material is subject to disposal. Primary polymerization irreversible.
To store paint residues, it is important to minimize contact with air. After use, close the lid tightly, having previously wiped the neck of the can from the paint to ensure tightness. You can flip the jar upside down for a few seconds to create an air plug from solvent vapor, which will prevent the formation of a film on the surface.
Store acrylic materials should be in a dark, cool place, away from fire sources and heating devices. The optimal storage temperature is indicated on the container, usually this range from +5°C before +25°C. Before reuse, the material that has been in the warehouse must be kept at room temperature for several hours and re-check the viscosity.
Can I mix paints from different manufacturers?
Theoretically, it is possible if they are on the same chemical basis (for example, both acrylic-polyurethane). But in practice, it is a lottery: there may be problems with the compatibility of hardeners and solvents, which will lead to defects. Better not take the risk.
Frequently Asked Questions (FAQ)
Can I dilute acrylic paint with water?
For car acrylic enamels and varnishes - categorically not. The water does not mix with organic resins and will cause stratification. Water is suitable only for special water-soluble bases, which are used in professional paint shops with special equipment.
What to do if the paint dries in the jar?
If a solid lump or film is formed throughout the thickness, throw it away. If the paint just became thick as sour cream, try adding a diluent and stirring a drill with a nozzle. If after 10 minutes of active stirring, the lumps have not dissolved, the material is spoiled.
Do you need a soil diluent?
Yes, acrylic soils also require dilution to working viscosity. Usually a more "coarse" diluent or the same universal is used for soils, but in larger proportions than for paint, to ensure good filling of the drawings and pores.
How to wash acrylic paint from the tool?
Until the paint is dried, it is easy to wash it off with a special washing solvent (for example, 646 branded
Does the diluent affect the color of the paint?
A quality diluent should not change color after drying. However, if too much solvent is used, the cover will decrease and the color may appear paler or more transparent, especially in darker colors.