Painting a car with a spray gun requires not only skill, but also the right choice of materials. Not only the final result depends on the type of paint, but also the complexity of the process, the durability of the coating, and compatibility with equipment. Beginners often make the mistake of choosing paint according to the principle “the more expensive the better,” without taking into account technical parameters: viscosity, type of thinner, drying speed and even climatic conditions in the workshop.
This article will help you figure out what kind of paint is needed for a spray gun depending on the task: be it local repair of chips, complete repainting of the body, or painting of plastic parts. We will analyze 4 main types of car enamels (acrylic, alkyd, nitrocellulose and water-based), compare them according to key parameters, and give a checklist for choosing a thinner. Let's look at it separately critical mistakes when mixing paint, which lead to “orange peel” or drips in 80% of defective cases.
1. Types of paints for spray guns: comparison by composition and application
All auto enamels are divided into groups according to the type of binder and solvent. Not only decorative properties depend on this, but also application technology, equipment requirements, as well as the environmental friendliness of the process. Let's look at each type in detail.
Acrylic paints (acrylic resin based) - the most popular choice for professional painting. They are two-component (paint + hardener), dry quickly and provide a durable coating with a deep shine. Suitable for all types of spray guns, but require precise mixing proportions. The main advantage is resistance to UV radiation and chemical detergents.
Alkyd enamels (based on alkyd resins) - a budget option for amateur painting. They are single-component, but take longer to dry and are less resistant to mechanical damage. Often used for painting rims or interior surfaces. An important nuance: when working with alkyd paints, you need respirator with carbon filter - their vapors are more toxic than acrylic ones.
Nitro enamels (based on nitrocellulose) - quick-drying paints that are applied in 3-5 thin layers. They give a bright gloss, but have low resistance to moisture and sunlight. Today they are rarely used, mainly for restoring retro cars or painting motorcycles. Require special thinner (No. 646 or No. 647) and high pressure in the spray gun (2.5-3 atm).
Waterborne paints - an environmentally friendly option that is gaining popularity in Europe. They are diluted with water, but require special aqueous thinners to adjust viscosity. The main disadvantage is high sensitivity to indoor humidity (optimally 50-60%). If not dried properly, dull spots may appear.
- 🔧 Acrylic: for professionals, durability 5-7 years, requires a hardener.
- 💰 Alcides: budget option, easy to apply, but toxic.
- ⚡ Nitro: fast drying, but low durability, rarely used.
- 🌱 Water: environmentally friendly, but capricious in terms of painting conditions.
2. Paint viscosity: how to measure and why it is critical
Incorrect viscosity is the #1 cause of paint defects. Paint that is too thick will cause "shagreen" (uneven texture), and liquid - to drips. The optimal viscosity depends on the type of spray gun, the temperature in the box and even the car model (for example, a thicker consistency is needed for vertical surfaces).
Viscosity is measured viscometer (funnel with a calibrated hole) and is indicated in seconds of expiration. Standard values:
- 🔹 Base layer (soil): 18-22 sec (at 20°C).
- 🔹 Acrylic enamel: 14-16 sec for HVLP, 16-18 sec for regular pistols.
- 🔹 Varnish: 12-14 sec (more liquid for uniform spreading).
If you don't have a viscometer, you can use stick method: Dip a clean wooden stick into the paint and lift it up. The optimal consistency is when the paint flows at a speed of 3-4 drops per second, leaving an even mark.
⚠️ Attention: Room temperatures below 18°C increase viscosity by 10-15%. If you do not correct it with a thinner, the paint will go on “dry” and lose its shine.
| Paint type | Optimal viscosity (sec) | Recommended thinner | Pressure in the spray gun (atm) |
|---|---|---|---|
| Acrylic (2K) | 14-16 | Acrylic thinner (fast/slow) | 1.5-2.0 |
| Alkyd | 18-20 | White spirit or thinner R-4 |
2.0-2.5 |
| Nitroenamel | 12-14 | Solvent No. 646 | 2.5-3.0 |
| Waterborne | 15-17 | Distilled water + 10% thinner | 1.2-1.8 |
For precise viscosity control, use thermometer in paint booth — when the temperature changes by 5°C, the viscosity changes by 8-12%.
3. Thinners: which one to choose and how not to spoil the paint
A thinner is not just a “dilution liquid”. It affects drying speed, paint flow and even the final shine. An error in choosing a thinner can lead to matte finish (if too slow) or microbubbles (if too fast).
Thinners are divided according to evaporation rate: Fast (for temperatures below 15°C), normal (18-25°C) and slow (above 25°C). For example, for acrylic paints in hot climates they use thinner "slow" (for example, Sikkens Autoclear LV) to avoid "dry fog" when spraying.
Suitable for alkyd paints white spirit or specialized thinners such as R-4. But nitro enamels require aggressive solvents - №646 or №647, but their excess can “burn” the paint, making it brittle.
- ❄️ Cold shop (<15°C): "fast" thinner (for example, Mobihel Fast).
- 🌡️ Normal temperature (18-25°C):"normal" diluent (PPG D8105).
- ☀️ Heat (>25°C):"slow" thinner (Spies Hecker 5600).
Bring the paint to room temperature (20-22°C)|Use a measuring stick for proportions|Add thinner in small portions, stirring|Check the viscosity after each addition|Filter the mixture through a 120-190 micron mesh-->
4. Compatibility of paint and spray gun: what you need to know
Not every paint is suitable for every spray gun. The main parameters to pay attention to:
Spray type:
- HVLP (High Volume Low Pressure) - optimal for acrylic and water-based paints, as it reduces material loss due to fog.
- LVLP (Low Volume Low Pressure) - universal, suitable for alkyd and nitro enamels, but requires a more liquid consistency.
- Conventional (regular) - used for thick materials (primer, putty), but produces more waste.
Nozzle size:
- 1.2-1.3 mm - for varnishes and liquid base paints.
- 1.4-1.5 mm - universal size for acrylic enamels.
- 1.6-1.8 mm - for primers and thick alkyd paints.
Example: if you paint metallic through an HVLP gun with a 1.4 mm nozzle, but did not reduce the pressure to 1.5 atm, the paint will apply in spots due to insufficient pigment atomization.
⚠️ Attention: Spray guns with an aluminum body are not recommended for use with water-based paints - they cause metal corrosion. Choose models with stainless steel or Teflon coating.
How to check the compatibility of paint and gun?
Mix a small amount of paint with thinner and spray onto the test surface. If:
- The spray pattern is even (oval or round) - compatibility is normal.
- “Tails” or drops appear - the pressure is too high or the nozzle is too large.
- The paint is “dusty” - you need to increase the viscosity or reduce the pressure.
5. Common mistakes and how to avoid them
Even professionals sometimes make mistakes that spoil the result. Here are the top 5 problems and their solutions:
- "Orange Peel" - occurs due to too thick paint or high pressure. Solution: reduce the viscosity by 10-15% or reduce the pressure to 1.2 atm.
- Drips - a consequence of liquid paint or slow passage of the gun. Solution: increase the distance to the surface to 20-25 cm and speed up the movement of the hand.
- Matt spots - appear when exposed to moisture or the wrong diluent. Solution: dry the part with a hairdryer and repaint with the correct thinner.
- Uneven color - typical for metallics with incorrect spray angle. Solution: hold the gun strictly perpendicular to the surface.
- Peeling paint - means poor adhesion. Solution: matt the old paint with sandpaper
P800-P1200and apply primer.
Pay special attention surface preparation: Even the most expensive paint will not work well on a greasy or dusty part. Use degreaser (for example, App Cleaner S) and sticky napkin to remove microparticles before painting.
90% of painting defects are not related to the quality of the paint, but to a violation of the technology: incorrect viscosity, dirty surface or incorrect pressure in the gun.
6. How to choose paint for specific tasks
There is no “universal” paint - the choice depends on the material of the part, operating conditions and even the color of the car. Considered scenarios:
Local repairs (chips, scratches):
Use acrylic paints in cans (for example, Motip or Dupli-Color) with a transition over the varnish. For precise color selection, use manufacturer code (located on a plate in the glove compartment or under the hood).
Full body repaint:
Optimal two-layer coating: acrylic base + varnish. For dark colors (black, blue), choose varnishes with UV filter (for example, Sikkens Autoclear Plus) to avoid burnout.
Painting plastic parts (bumper, mirrors):
Plastic requires special soil (for example, PPG DP40LF) and flexible paint (acrylic with plasticizers). Without primer, the paint will crack in 2-3 months.
Wheel painting:
Wheels are painted alkyd enamels (for example, Kudo KU-6000) or powder paints (for durability). Important to use heat-resistant compounds, withstands heating up to 200°C.
| Problem | Recommended paint | Soil | Varnish |
|---|---|---|---|
| Local repair | Acrylic in a can (Motip) | Epoxy (Novol Protect 360) | Acrylic (Mobihel HS) |
| Complete repainting | Acrylic base (PPG Deltabase) | 2K primer (Sikkens Autowave) | 2K varnish (Spies Hecker Permahyd) |
| Plastic (bumper) | Acrylic with plasticizer (Lesonal) | Primer for plastic (PPG DP40LF) | Flexible varnish (Mipa 1K Flex) |
| Discs | Alkyd heat resistant (Kudo KU-6000) | Acidic soil (Novol 440) | Not required |
7. Top 5 manufacturers of paints for spray guns
The quality of the paint directly affects the result. We analyzed reviews from professionals and identified five brands that are trustworthy:
- PPG (Deltabase, Omni) — leader in color rendering, used in official services Audi and BMW. Feature: system Envirobase with low volatile matter content.
- Sikkens (Autowave, Autoclear) - the best choice for complex metallics. Technology Autoclear Plus guarantees a mirror shine without polishing.
- Spies Hecker (Permahyd, Standoblue) — optimal for the climatic conditions of Russia. Paint series Permahyd dry at low temperatures (up to +10°C).
- Mobihel (Pro-Spray, HS) - budget professional option. Popular among craftsmen for their price/quality ratio.
- Lesonal (Basecoat, 2K) - German quality for amateur painting. Easy to tint, suitable for HVLP guns.
When choosing a brand, pay attention to guaranteed shelf life paints For example, PPG Deltabase retains its properties for 3 years if properly stored, and cheap analogues can delaminate after 6 months.
Saving on paint costs more: cheap enamels require more layers, take longer to dry and are more likely to cause defects. The optimal balance is mid-price segment brands (Mobihel, Lesonal).
FAQ: Frequently asked questions about spray paint
Is it possible to thin acrylic paint with white spirit?
No, white spirit is not compatible with acrylic paints. It does not dissolve acrylic resins, which will lead to curling paint and clogging the gun nozzle. Use only special acrylic thinners (for example, PPG DX330 or Sikkens Thinner).
Which spray gun is best for waterborne paint?
For water-based paints, guns with stainless steel parts (for example, Satajet RP or Iwata W-400). Required condition: nozzle 1.3-1.4 mm and pressure 1.2-1.5 atm. Conventional aluminum spray guns quickly corrode from water.
How many layers of paint should I apply?
The number of layers depends on the type of paint:
- 🔹 Acrylic base: 2-3 layers (drying between layers 5-10 minutes).
- 🔹 Varnish: 2 layers (the first is “wet on wet”, the second - after 15-20 minutes).
- 🔹 Alkyd enamel: 3 layers with drying 20-30 minutes.
Important: each layer must be thin - a thick layer will cause drips.
Why did the paint become dull after drying?
There are several reasons:
- Used wrong thinner (eg "fast" at low temperature).
- There was high humidity (>70%), which led to condensation on the surface.
- Paint applied too thick layer, and the top layer “sealed” the solvent inside.
Solution: polish the defective areas with paste 3M 09374 or repaint with the correct thinner.
Do I need to paint it in two colors (base + varnish)?
It depends on the type of paint:
- 🔹 Acrylic 2K: require varnishing for protection and shine.
- 🔹 Alkyd enamels: often one-component and do not require varnish (but are less durable).
- 🔹 Nitro enamels: varnished only for additional protection.
For metallics and pearls varnish required — it “raises” the effect of glitter.