Painting a car with a brush or roller is a thing of the past, giving way to professional equipment that ensures perfect smoothness and uniformity of the layer. Pulverizer (or spray gun) is the main tool in any painter's arsenal, allowing you to turn liquid paint into a fine mist. It is this “fog” that settles on the surface of the body that forms the very factory effect that all restorers strive for.
However, the tool itself does not guarantee results - you need to clearly understand how to use a paint sprayer to avoid smudges, shagreen and uneven color. Errors in setup or movement technique can cost you time and expensive materials, so you need to approach the process with maximum responsibility and theoretical preparation.
In this article we will analyze all the nuances of working with a sprayer: from choosing the viscosity of the material to final cleaning of the nozzle. You will learn how to adjust the torch, what pressure to set in the compressor and what hand movements are considered standard for obtaining a flawless coating.
Selecting and preparing a spray gun for work
Before you start mixing components, you need to decide on the type of equipment. For body work, pneumatic models of systems are most often used. HVLP (High Volume Low Pressure) or LVLP (Low Volume Low Pressure). The former require a large volume of air, but provide high material transfer, the latter are more economical and less demanding on compressor performance.
A critical step is preparing the paint itself. The material must be thoroughly mixed and, more importantly, filtered through a special funnel filter. Even a microscopic speck that gets into nozzle (nozzle), can completely change the geometry of the torch or cause paint to spit during operation.
Why can't filtering be ignored?
Many beginners neglect straining, considering modern paint to be perfectly clean. However, there are often undissolved pigment clumps or dust in the jar. When they enter the spray gun channel, they create turbulence, which leads to uneven spraying.
The viscosity of a material is a parameter that cannot be determined by eye. To measure, use a viscometer (funnel), lowering it into a container of paint and timing the flow of the stream. If the time is not within the manufacturer's recommendations (usually 14-18 seconds for base coat), add thinner. Paint that is too thick will look like an orange peel, and thin paint will flow.
Use only solvents recommended by the paint manufacturer. A fast solvent can dry out while still in the air, creating dry shagreen, while a slow solvent will cause drips.
Adjusting the pressure and shape of the torch
Adjusting the spray gun is a balance between three parameters: air supply, material supply and torch shape. Air is supplied from a compressor, and its pressure at the inlet to the tool must strictly comply with the technical requirements of the model. Usually this value is in the range from 2 to 3 atmospheres, but the exact data is always indicated in the product data sheet.
The shape of the torch is adjusted by the upper screw on the body of the spray gun. To paint large surfaces (hood, roof, doors), the torch should be as wide as possible, almost elliptical. For hard-to-reach areas, arches or narrow counters, it is advisable to switch to a round spray pattern by tightening the adjuster.
☑️ Setting up before the test
Do not forget that the pressure must be adjusted when the trigger is pressed, when the air freely leaves the head. If you adjust “to closed”, then when you start working, the actual pressure will drop and the spray quality will deteriorate. Test Spray on cardboard or an old part - a mandatory procedure before going out to the car.
A correctly configured torch has clear boundaries and uniform density over the entire area, without breaks or compactions in the center or along the edges.
Technique for applying paint to the body
The most important secret to an even surface lies in the movement of your hand. The spray gun should always be positioned strictly perpendicular to the surface to be painted. Any deviation in the angle will result in the layer being thicker on one side and thinner on the other, causing a difference in tone.
The distance from the nozzle to the body also plays a decisive role. The optimal range is 15–20 centimeters. If you bring the tool closer, drips will inevitably form due to excess material. If you hold it further, some of the paint will dry in the air before reaching the surface, which will make the coating matte and rough.
Movements should be smooth, carried out using the body, and not just the hand. The speed of movement should be uniform: approximately 40–50 cm per second. Start moving your hand before pressing the trigger and finish after you have passed the edge of the part so as not to “spit” on the fresh paint.
- 🎨 Apply the first layer (primer/base) quickly and thinly, covering the previous pass by 50%. This is necessary for bonding to the surface.
- 💧 Make the second and subsequent layers slower and more saturated, but make sure that the paint does not start to flow.
- 🔄 Be sure to allow “interlayer drying” according to the instructions on the can (usually 10-15 minutes) so that the solvent has time to evaporate.
Pay special attention to edges and complex terrain. A mistake often occurs here when the master forgets to paint the sides, and as a result, when opening the door, a sharp color transition or underpainting is visible.
Comparison of material spraying techniques
Different types of automotive enamels require an individual approach. Metallics and pearls are more capricious than plain acrylics, as they contain reflective particles. Improper application of metallics can result in a “apple effect” (mottling), where the color appears uneven in different lighting conditions.
Varnishing is the final stage that creates gloss and protection. The varnish is usually applied in two layers: the first is thin (binder), the second is full, glossy. It is important here not to overdo it with thickness, otherwise the varnish may “boil” or become cloudy.
| Parameter | Base coat (Metallic) | Acrylic enamel (Solid) | Varnish (2K) |
|---|---|---|---|
| Number of layers | 2-3 thin | 2-3 medium | 1 binder + 1 full |
| Interlayer drying | 10-15 minutes | 15-20 minutes | 10 minutes (until matte) |
| Distance to part | 15-20 cm | 20-25 cm | 20-25 cm |
| Pressure (atm) | 2.0 - 2.5 | 2.5 - 3.0 | 2.5 - 3.0 |
Typical defects and methods for eliminating them
Even experienced painters sometimes encounter defects. Understanding the causes of defects allows you to quickly correct the situation. For example, shagreen (orange peel effect) most often occurs due to too viscous paint, low air pressure or a long distance to the surface.
⚠️ Attention: If you notice that the paint has begun to spread (a smudge has formed), do not try to immediately shade it with a brush or add another layer. Stop, let the defect dry, then sand it down and re-coat the area.
Dry spraying, when the paint is rough and matte, indicates too rapid evaporation of the solvent or excess pressure. In hot weather, use “slow” solvents so that the paint has time to spread over the body before polymerization.
Another common problem is fisheye (craters). This occurs if traces of silicone, oil or wax remain on the degreased surface. The paint simply pushes off from these points, forming circular indentations. The only way to combat it is through thorough washing, degreasing with special wipes and the use of anti-silicone additives.
- 🌫️ Milky plaque (whiteness) appears when air humidity is high or a cold solvent is used.
- 🕸️ Cobwebs (thread-like smudges) occur when the spray gun is abruptly removed from the surface at the end of the passage.
- 🍊 Large shagreen is often treated by polishing, but it is better to prevent it by properly setting the nozzle.
Tool care and cleaning after use
The lifespan of your spray gun directly depends on how you wash it. It is strictly forbidden to leave paint inside the tank or channels “until tomorrow”. It will harden, and it will be almost impossible to clean the thinnest channels without the risk of damaging the calibrated holes.
The washing process begins immediately after completion of work. Drain off the remaining paint, pour solvent into the tank and spray it to clean the internal line. Then disassemble the head, remove the needle and nozzle, wipe them with a soft brush dipped in solvent.
⚠️ Attention: Never use metal brushes or hard wires to clean the nozzle! You will irrevocably disrupt the calibration of the hole, and the torch will no longer be symmetrical. Use only the soft brushes included in the kit.
After washing, be sure to lubricate the moving parts (needle, trigger, adjustment screws) with a special lubricant for paint sprayers. This will prevent parts from souring and ensure smooth running in the future. It is better to store the tool disassembled or in a special case to protect the head from mechanical damage.
High-quality washing takes no more than 10 minutes, but extends the life of an expensive instrument for years and guarantees stable results in the future.
Frequently asked questions (FAQ)
What is the optimal air pressure for an HVLP spray gun?
For most HVLP system models, the operating pressure at the inlet to the tool should be 2.0–2.5 atmospheres. However, always check the specific model data sheet as requirements may vary depending on the nozzle diameter.
Is it possible to paint a car in a garage without a professional camera?
It is possible if you ensure there is no dust or drafts. Before painting, it is necessary to moisten the floor generously with water to remove dust and provide good lighting. It is important that there are no particles hanging in the air that could settle on the fresh varnish.
What to do if the spray gun starts spitting paint?
Most likely, the nozzle is clogged or the paint in the tank has run out and air is coming out. The cause may also be a loose tank or needle. Stop, check the paint level and clean the nozzle if necessary.
How to dilute paint that has thickened in a tank?
If the paint begins to thicken while working, add a little solvent of the same brand and mix thoroughly. Do not pour pure solvent or gasoline - this can ruin the chemical structure of the coating.