How to dilute water-based paint for a spray gun

I want to carry out any finishing work as soon as possible so that the car or painting walls and ceilings, the room gets an attractive appearance, and can be used for its intended purpose. That is why today less and fewer home craftsmen take up brushes and rollers and prefer painting from a spray gun.

This technology allows you to get a perfectly smooth and smooth coating in a matter of minutes, and at the same time spend a minimum of effort. But in order for the result to meet expectations, you will have to follow certain rules.

For example, it is correct to determine which paint is suitable for a spray gun in your case, and how to properly dilute it. This is what you will learn from this article.

Why dilute the paint

As is known, the diameters of the spray gun nozzles can vary significantly and vary in the range: from 0.1 to 4 mm. And we still do not take into account cartouche pistols, which are also included in this group of tools.

Having judged logically, it becomes clear that an airbrush with a nozzle of 0.1 mm will clearly not be able to actively spit out thick enamel, but will require a mixture of the most liquid consistency.

At the same time, if such “colored water” is poured into the tank of a spray gun with a nozzle of 4 mm, then when working it will break it into very large drops that will begin to form smudges on the surface.

Based on this, before you figure out how to dilute the paint for the spray gun at home, you should clearly determine what diameter the nozzle is installed on your tool.

Varnish coating

Applying varnish to the surface

Before you start applying the varnish, it must be diluted with a solvent and a fixative in accordance with the manufacturer's instructions. It is usually applied in two or three layers. For the first application, it is diluted weaker.

The painting technology assumes mandatory drying of each layer (as well as the base). Often the masters check whether the varnish has dried by touching the surface with a finger in an inconspicuous place.

If the finger sticks slightly, but the varnish is no longer smeared, you can paint further. But still, you should not rush, and it is better to apply the next layer on the completely dried previous one. It is necessary to avoid smudges, because it is quite difficult to remove them.

Usually, this will require completely removing the layer. As for the effect of shagreen leather, which may appear on the surface, you can get rid of it by polishing or sanding a layer of varnish (after it is completely dry).

Types of paints

The principle of operation of the spray gun allows it to spray absolutely any fluid materials. To date, there are dozens of paint manufacturers on the market with thousands of various variants of mixtures. It is impractical to analyze each product separately, but we will tell you about 5 main groups, from which all possible derivatives come.

Alkyd enamels

They are created on the basis of varnish in a mixture with various solvents, fillers and color pigments. It is widely used for covering wood, metal and even concrete. As a diluent of alkyd enamel, white spirit is often used.

Acrylic paints

They are based on polymers of esters. They are most often used in painting. As a material in finishing works, they can be applied to wood, metal and plaster. They are diluted with ordinary or distilled water at room temperature.

Water-based emulsion paints

Like acrylic, they are made on the basis of polymers mixed with water and coloring pigments. Incredibly popular in construction and finishing works, as the cheapest and most practical material. All water-dispersed paints can be diluted with ordinary, clean water.

Oil paints

They are a combination of inorganic dyes with fillers mixed in drying oils or vegetable oils. They have a high toxicity, but a very bright shade. For example: an excellent metal paint for a spray gun, it has a lead meerkat in its composition. Oil paints are widely used in production, when working with metal or plastic. They are diluted with white spirit, foam, turpentine and other solvents.

Nitroemali

They are made on the basis of nitrocellulose varnish mixed with inorganic pigments. It is widely used when working with metal, often in the painting of car bodies. When choosing a spray gun for metal paint, from which nitroemal will be sprayed, it is necessary to consider tools only with a metal body. You can dilute this type of paint with white spirit, solvent 646 or a special composition recommended by the manufacturer.

What to choose a paintwork for a car

There are several types of paints that are used for painting a car. Today, four of their types are most often used:

acrylic enamels that have the ability to dry quickly, forming a strong, shiny layer;
To choose the right solvent, you need to know the composition and properties of the paint used
alkyd car paints that require prolonged drying, which form a surface resistant to mechanical or chemical influences;
nitroemals, the coating of which has a low resistance to external factors, one of the most popular nitrocracks is synthetic enamel with the effect of metallization (metallic);
water-based paints, which are used recently, but are already gaining popularity due to their environmental friendliness.

Each owner must decide for himself what material to choose for painting a car based on its properties or cost.

Determination of viscosity

The consistency of the substance can be very approximate, especially when it is determined " by eye”, without the use of special equipment, and even more so, experience. Of course, you can always refer to the fluidity of certain common liquids (oil, kefir, shampoo), but it will never be possible to achieve accurate indicators in the same way.

Namely, the basis of uninterrupted quality of work is the ability to establish the exact viscosity of the paint for the spray gun. The viscosity of the paint is determined by a simple device-a viscometer, and the data obtained are calculated in DIN units or seconds (in domestic models).

The device of the viscometer is extremely simple and consists of a 100 ml container with a hole of 4, 6 or 8 mm and a holder that can be removable. Budget models are made of plastic, and more professional ones are made of polished metal. How to use a viscometer to measure the viscosity of paint, we will tell you about the points:

How to dilute it

The uniformity of the ready-to-apply mixture largely depends on the component used in dilution. Before you dilute the paint for the spray gun, you should read the manufacturer's recommendations on the package, since each paint and varnish material has its own unique composition.

Unfortunately, there is no universal means for diluting paint, and although we know such famous solvents as 646 or white spirit, they are not suitable for all paint and varnish mixtures.

For example, acrylic-urethane paint, it is best to dilute with a solvent P-12, and if you use the previously specified means, you can burn the coloring pigment.

You can use universal solvents only if you do not know the name of the paint and pour it from an unnamed canister. Or, if the quality requirements are as low as possible. In other cases, you should follow the recommendations on the packaging of a specific mixture or on the official website of the manufacturer.

How to breed different car enamel compositions?

The use of thick paint when painting a car leads to an unsightly result — various defects, swellings and shagreen. Applying a viscous auto enamel with a spray gun causes the absence of a mirror shine and an attractive appearance of the body.

The paint must be diluted immediately before performing the procedure for painting the surface of the vehicle body. Compliance with the mixing proportions of the compositions and the correct choice of solvent will ensure high-quality trouble-free application of auto enamel and a fast drying process.

Dilution of the paint allows you to achieve an ideal viscosity of the paint composition, sufficient to cover the entire area of the car body. The wrong choice of solvent can lead to problems in the coloring process — poor adhesion to metal surfaces, delamination, the formation of thick lumps and "flakes".

Please note!

Before choosing how to dilute the paint, you should carefully read the instructions on the packaging of the car enamel. Many manufacturers of paint coatings give recommendations on the use of their products and the choice of a solvent.

Different solvents are suitable for certain types of automotive paint:

· White spirit.

It is used mainly for degreasing and cleaning the painted surface of the body before applying enamel. Suitable for slate or rubber-bitumen mastic, it is not recommended to use it for diluting acrylic enamel;

· №646

An aggressive solvent that not only reduces the degree of viscosity of the paintwork, but also leads to a change in its chemical composition. With caution, it should be used in combination with acrylic paint and some types of primers;

· №647.

The solvent is used with automotive lacquers and nitrocracks, it has an aggressive effect;

· Multicomponent composition of P-4.

Contains acetone or toluene in the composition, is used for diluting alkyd enamels;

· Toluene and xylene

are intended for dilution of paint containing a chlorinated polymer.

Please note!

When choosing a suitable solvent, it is necessary to take into account the degree of polarity of the paint material. If liquid hydrocarbons are used in the manufacture of enamel, kerosene or white spirit is suitable for diluting it, the presence of hydroxyl group molecules indicates the polarity of the enamel, which alcohols and ketones are suitable for diluting.

Acrylic car enamels contain a certain amount of water in the composition. Reducing their degree of viscosity before use requires the addition of a hardener followed by the introduction of a solvent. Economical and budget dilution options are such diluents as No. 651 and P-12.

Pure toluene or xylene, as well as multicomponent P-4, are suitable for alkyd enamel. The use of nitro paint to give the car body a metallic shining effect requires a competent choice of diluent, usually paint manufacturers indicate the recommended composition in the instructions on the package (for example, No. 646).

When choosing a solvent for paint, in addition to its type and polarity, it is necessary to take into account the temperature dependence. Some diluents are positioned as universal, others are designed for use at a specific ambient temperature (negative or positive).

When diluting the paint, it is worth considering the recommendations:

When painting at a normal temperature (15-20 degrees), the enamel must be dissolved for 3-5 %;
At a reduced and subzero temperature, the solvent should be added in a larger amount — at least 5-10%.

The appearance of the car is a very important factor that can tell a lot about both the owner and the vehicle itself. With the help of well-executed painting, even the oldest car can be transformed, and the quality of this procedure strongly depends on the chosen automotive solvent. Therefore, it is very important to know what solvent to dilute the car paint with.

According to the chemical composition, organic solvents for painting cars practically do not differ from other solvents for enamels and paints that are used in production and in everyday life. Automotive solvents should perform three functions:

Clean and degrease surfaces.
Dilute the paint to the desired consistency.
Wash tools after work (for example, a spray gun).

The choice of a solvent for car paints is determined by the type of work carried out and the characteristics of the composition for painting.

The main indicators of solvents for car paints are: density, appearance, fire hazard level, acidity, flash point, degree of toxicity, water content, volatility, as well as the content of chemical impurities.

But still, the main characteristic is the degree of volatility, or in other words, the rate of evaporation of the solvent on the surface to be painted. According to the degree of volatility, solvents are classified into slow (suitable for painting a car in the summer), universal (for work in the off-season, have an average degree of evaporation), fast (used in winter).

How to dilute the paint

The most important stage of the entire above guide. It requires increased accuracy, accuracy, and most importantly, regularity. For most lacquers and enamels, the percentage of the infused diluent is 5-30% of the total volume, and for water-based paints, it can even reach 50%.

Therefore, in order to understand how to dilute the paint for the spray gun correctly, it is necessary to determine its initial viscosity using the above-mentioned viscometer. If the consistency is too thick, it is lowered by pouring small portions of diluent, mixing thoroughly and re-measuring, until the viscosity becomes optimal.

You can focus not only on the data of the viscometer, but also on the filling of the composition indicated on the package (concentration). Paint and varnish mixtures can be low-filled, medium-filled and high-filled. Low-filled paints usually have enough 5% ± 3%. Highly filled ones can be diluted up to 30%. Medium-filled compositions are diluted within the limits, between the two previous ones.

As a concentration designation, some manufacturers indicate the following marking on the containers (the values are indicated in increasing order: from liquid to viscous):

Having determined the viscosity, you can start the mixing process. It is better to do this in a cylindrical container with smooth walls (like a regular paint can). As a stirrer, you can use a regular sanded stick without burrs, or a metal ruler, which is also recommended to smooth the edges. To mix larger batches, you can use a drill with a special nozzle in the form of a crosspiece.

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