Choosing the right paint material is the foundation of quality painting, whether it is the car body, interior details or building structures. Many beginners make the mistake of believing that you can pour any liquid substance bought in the nearest store into the spray gun. Actually, What kind of paint for the spray gun is suitableIt depends on many factors: the type of sprayer, the diameter of the duse, the pressure of the compressor and, of course, the chemical basis of the material itself.
The use of the wrong composition will inevitably lead to defects: shaking, leaks, “orange peel” or even complete failure of the pneumatic tool. A thick emulsion will clog the channels, and a too liquid one simply flows from the surface without creating a protective layer. Therefore, before starting work, it is necessary to clearly understand the difference between the types of coatings and be able to properly prepare them for application.
In this article, we will discuss the technical nuances of the selection of materials, methods for determining viscosity and specific dilution proportions for different types of paints. You will learn to distinguish finished mixtures from concentrates and understand why saving on solvent can cost you a spoiled project.
The main types of paints for pneumatic application
The modern market offers a wide range of paints (varnishes), and each of them has its own application features. The most common for pneumatic application are acrylic, alkyd, nitrocellulose and water-dispersion compositions. Acrylic enamel They are considered universal: they dry quickly, have excellent cover and are suitable for both cars and furniture. They are often used with hardeners to create a durable coating.
Alkyd paints They form a harder and more glossy film, but require more time to dry and often emit a pungent odor when applied. They are excellent for metal surfaces exposed to atmospheric stress. At the same time, water-dispersion compositions are gaining popularity due to environmental friendliness and lack of smell, but they are more capricious to air temperature and humidity in the room.
Separately, it is worth mentioning two-component materials, such as epoxy soils or polyurethane varnishes. They require mixing the base with the hardener immediately before use. Viability Such mixtures are limited by time (usually from 2 to 6 hours), after which the material begins to polymerize directly in the spray gun tank, which can lead to its breakage.
When choosing a material, always pay attention to the manufacturer's labeling. If the can says “Ready to spray” (ready to spray), this means that the product already has optimal viscosity. If you have a concentrate in front of you, you will need to solvent appropriate stamp. Incorrect selection of chemistry can lead to the curling of the paint or change its color.
⚠️ Warning: Never mix paints on a different basis (e.g. acrylic with alkyd or oil with water). This will lead to a chemical reaction, the formation of flakes and complete deterioration of the material that you have to throw away.
Critical parameter: viscosity and spreading time
The main answer to the question of what paint for spray gun is suitable lies in the viscosity parameter. This is the resistance of the fluid to the flow, which directly affects the quality of the spray torch. Viscosity is measured in seconds by viscometer (Ford cup) or in DIN units. For most pneumatic spray guns, the optimal viscosity is between 18 and 22 seconds at a temperature of 20°C.
If the material is too viscous, the spray gun will “spit” with large drops, creating a rough shaft. The compressor pressure may not be enough for high-quality crushing of the jet. If the paint is excessively liquid, it will give abundant flows and will not be able to cover the lower layer, requiring the application of many additional layers, which increases the flow.
Use a viscometer funnel for accurate measurement. If it is not at hand, experienced masters test the viscosity "by eye", watching the stream flowing from the stirring stick: it should be intermittent, but not drip like water.
The temperature of the environment plays a key role. With increasing temperature, the viscosity drops, and the paint becomes thinner. Therefore, the dilution proportions indicated on the bank are recommendatory and often require adjustment “on the spot”. In hot weather, it may be necessary to add a “slow” solvent so that the paint does not dry out in the air (dry spraying).
For different types of materials, the viscosity norms may differ:
- 🎨 Filling ground require higher viscosity (20-25 seconds) to fill the irregularities and not shrink.
- 🚗 Basic enamel (metallic, pearl) are applied with more liquid (16-18 sec) to create a smooth decorative layer.
- 🛡️ Lacquer and two-component enamel have average values (18-20 seconds) for the formation of a smooth glossy film.
Technology of preparation and dilution of materials
Even if you know exactly what paint for spray gun is suitable for type, it must be properly prepared. The process begins with a thorough mixing. Pigments and particulate matter often settle to the bottom of the jar, and simple shaking may not work. Use a drill with a mixer nozzle to obtain a homogeneous mass.
After stirring, add the solvent. The proportions are usually specified by the manufacturer in the format of 10:1, 4:1 or 2:1 (basis: solvent). As mentioned earlier, however, these figures may vary. Add the solvent gradually, constantly monitoring the viscosity. The sudden addition of a large volume of chemistry can disrupt the structure of the binder.
☑️ Preparing paint for work
The final and mandatory stage is filtration. The paint may contain foreign inclusions, dust or poorly dissolved particles. Getting into the duo of the spray gun (especially if its diameter is 1.3 mm or less), they will cause spitting or completely block the supply of material. Use special funnels with a net or capron stockings.
⚠️ Note: Do not use metal mesh with too large a cell or, conversely, gauze, which can leave the villi in the paint. Optimal nylon filters-funnels 125-190 microns.
When working with two-component materials (soils, varnishes), remember about the “life of the mixture”. After adding the hardener, an irreversible chemical reaction begins. Do not open a bucket of varnish immediately if you do not have time to develop it in 40-60 minutes. Better to cook in portions.
Selection of the diameter of the duse depending on the material
The diameter of the spray gun’s output (duse) is the second key factor determining which paint is right for your tool. Duze should correspond to the viscosity of the material. If you try to spray thick soil through the duse of 1.3 mm, you will spend hours on unsuccessful attempts to adjust the torch, and the result will be deplorable.
For liquid materials such as grills, solvents or liquid primers on metal, duzes with a diameter of 1.2-1.3 mm are suitable. They create a fine mist, lie perfectly on the surface, but are not able to miss large particles of filler. An attempt to pour thick enamel into such a gun will lead to constant blockages.
The universal size is considered to be a dusa of 1.4-1.5 mm. It is suitable for applying most acrylic enamels, base layers of "metallic" and even some varnishes. This is the best choice for a home craftsman who doesn’t want to buy a set of three different spray guns.
Secrets of the professionals
Many painters have a separate spray gun for varnish with a duse of 1.5-1.6 mm and a separate one for a base with a duse of 1.3 mm. This allows you to avoid washing the gun thoroughly between stages and reduces the risk of dust.
For thick materials – acrylic soils-fillers, liquid putty (within certain limits) or antigravel – duzes with a diameter of 1.7-2.0 mm and above are required. These guns are often called “shooters”. They miss out on large factions and require more pressure to form a torch.
| Type of material | Recommended diameter of duse (mm) | Pressure at the entrance (Bar) | Features |
|---|---|---|---|
| Morilks, solvents | 1.2 - 1.3 | 2.0 - 2.5 | They require very small spray. |
| Basic enamel (metallic) | 1.3 - 1.4 | 2.5 - 3.0 | It is important not to overflow to avoid leaks. |
| Acrylic enamel, Lacque | 1.4 - 1.6 | 3.0 - 3.5 | Optimal for finishing surfaces |
| Sound filler | 1.7 - 2.0 | 3.5 - 4.0 | You need high pressure to break through. |
Solvents: 646, 647 or specialized?
A common question among beginners: can you use a universal solvent? 646 or 647 for all the colors? The answer is no. Although these solvents are cheap and affordable, they are an aggressive mixture of alcohols, ketones and esters. Their use in acrylic two-component systems can cause varnish clouding, a change in the shade of metallic or even swelling of the bottom layer of paint.
For professional work it is necessary to use solvent (Dilluents) recommended by the paint manufacturer. They are divided by the rate of evaporation:
- 🐢 Slowly. - for hot weather and large areas, so that the paint has time to spread.
- 🐇 Fast. - for cold weather or small parts to speed up drying and avoid dust.
- 🌡️ Normal. - universal variant for standard conditions (20°C).
Using an inappropriate solvent is one of the main causes of the defect of “boiling” or “craters”. The aggressive components of a cheap solvent can begin to actively evaporate, cooling the surface and condensing moisture from the air, leading to whitish plaque.
Savings on solvent are false. The cost of a can of the right diluent is negligible compared to the risk of redoing all the work due to defects or buying a new paint.
Always check the compatibility of the solvent and paint. If you use the products Mobihel, Brulex or PPGBuy a branded diluent of the same brand or its qualitative analogue with a similar chemical formula.
Typical errors and troubleshooting
Even knowing the theory, masters face problems when applying. Let's look at the frequent situations. If the paint is laid in stripes or the torch is shaped like a dumbbell (two horns), the side channels of the airhead are likely clogged or there is insufficient pressure. It is necessary to clean the dusa and increase the pressure by 0.5 atm.
The appearance of shaven ("orange peel") often indicates that the paint is too thick or dries too quickly. In this case, you need to add a little diluent and perhaps replace it with a slower one. It may also be because the gun is too far from the surface.
If you have a lot of swelling, check:
- Is it too liquid paint (add the basics)?
- Aren't you driving the gun too slowly?
- Is the torch too heavily covered (reduce the supply of material).
⚠️ Warning: After work, be sure to wash the spray gun immediately! The dried paint inside (especially two-component) turns into stone, and it will be almost impossible to clean the channels without the risk of damaging the seals.
Proper washing consists in the spill of the system with a clean solvent, disassembling the needle and airhead, and lubricating the moving parts with a special oil for pneumatic tools. This will extend the life of your instrument for years.
Frequently Asked Questions (FAQ)
Can I paint with water-based paint?
Yes, you can, but certain conditions are required. Water-based paints should be diluted only with water (up to 10%), use a spray gun with a plastic or stainless needle (ordinary steel can rust) and a duse of 1.5-1.8 mm. It is important to avoid draughts when drying.
What is the difference between paint for spray gun from paint for roller?
Paint for roller often has a higher viscosity and contains coarse fillers that will not pass through the due of the spray gun. To spray such compounds must be carefully filtered and diluted more, which can reduce their cover.
Why is the paint foaming in a spray gun?
This is due to too much stirring before pouring or the use of the wrong (too fast) solvent. Let the paint stand for 10-15 minutes before applying, so that the air bubbles come out.
What compressor is needed to work with a spray gun?
For amateur work, a capacity of 200-250 liters per minute and a pressure of 8 bar are enough. However, it is important that the receiver was at least 24-50 liters, otherwise the pressure will be downloaded, and the torch will “spit”.
Can I mix paints from different manufacturers?
It's not recommended. The chemical composition of binders can vary from brand to brand, leading to unpredictable reactions, color changes, drying times and coating durability.