Painting a car is not only an art, but also an exact science, where every detail affects the final result. One of the key elements that beginners often overlook is spray gun nozzle. Its size and type determine the uniformity of the layer, material consumption, and ultimately the appearance of your car after repair. The wrong choice can lead to streaks, shagreen, uneven coverage or even defects that will appear months later.
In this article we will look at how to choose a nozzle for specific tasks: from local repairs to complete repainting, from acrylic to metallic. You will find out what nozzle sizes (from 0.8 mm up to 2.0 mm) what they are intended for, how the type of sprayer affects the texture of the coating, and why professionals always have several replaceable nozzles in their arsenal. We’ll also reveal secrets that will help you save on materials without losing quality.
Whether you're painting your car for the first time or want to optimize the process, this information will save you time, money and stress. Let's start with the basics.
What is a nozzle and how does it work
The nozzle (or nozzle) of a spray gun is a small hole through which paint and varnish material is supplied under pressure. Its diameter is measured in millimeters and determines two key parameters:
- 🔹 Material consumption — the larger the diameter, the more paint passes per unit of time.
- 🔹 Layer thickness — small nozzles give a fine spray, large nozzles give a denser “torch”.
- 🔹 Coverage type - acrylic, metallic or varnish require different approaches.
It is important to understand that the nozzle works in tandem with air cap (it forms a torch shape) and pressure at the entrance. For example, nozzle 1.3 mm at pressure 2.0 bar will behave differently than when 1.5 bar. Professional painters often adjust the pressure for a specific task, but for beginners it is easier to focus on the standard settings of the spray gun manufacturer.
One more nuance: the nozzle material. Most modern nozzles are made of stainless steel or Teflon. Teflon less clogged and easier to clean, but more expensive. Steel more wear-resistant, but require careful care after working with aggressive solvents.
Main nozzle sizes and their purpose
The nozzle diameter is selected to suit material viscosity and type of work. Below is a table with recommendations for the most common tasks:
| Nozzle size (mm) | Material type | Scope of application | Pressure (bar) |
|---|---|---|---|
0.8–1.0 |
Varnishes, thinned paints | Local repairs, retouching, thin layers | 1.5–2.0 |
1.2–1.3 |
Acrylic paints, base coats | Full paint, metallics, pearls | 2.0–2.5 |
1.4–1.5 |
Primers, liquid putty | Application of fillers, anti-corrosion works | 2.5–3.0 |
1.6–1.8 |
Thick varnishes, two-component paints | Final layers, chip protection | 3.0–3.5 |
2.0+ |
Putties, anti-gravel coatings | Surface preparation, rough work | 3.5–4.0 |
A critical mistake for beginners: using a 1.4–1.5 mm nozzle for metallics. This results in uneven distribution of aluminum particles and "spotting" after drying. Optimal size for metallics 1.2–1.3 mm — it ensures uniform dispersion of the pigment.
When choosing, also consider climatic conditions:
- In hot weather (>25°C) it is better to use the nozzle on 0.1mm less — the paint dries faster, and the risk of drips is higher.
- At low temperatures (<15°C) or high humidity, on the contrary, increase the diameter by 0.1 mm for better fluidity.
Types of nozzles: what they are and what they are needed for
In addition to size, nozzles vary in design and spray pattern. Here are the main types:
- 🔧 Standard (round) - a universal option for most jobs. They produce a uniform torch, but require precise pressure adjustment.
- 🔧 Oval — used for painting large surfaces (hood, roof). Allows you to reduce operating time by 20–30%.
- 🔧 Tapered (tapered) — optimal for complex surfaces (arches, thresholds). Minimize material waste.
- 🔧 Two-component - for mixing paint and hardener directly in the nozzle. Used in industrial environments.
Separately worth mentioning adjustable jet nozzles. They allow you to change the spray width without changing the nozzle - convenient for working with different parts. However, such models are more expensive and require more careful maintenance.
The best choice for beginners is standard round nozzle 1.3 mm. It forgives small mistakes in setting the pressure and is suitable for 80% of car painting tasks. Experienced painters often use a set of nozzles (for example, 1.2, 1.3 and 1.5 mm) for different stages of work.
How to check the quality of a nozzle before purchasing?
Before purchasing, inspect the nozzle against the light: the inner surface should be perfectly smooth, without burrs or scratches. Also check that the threads match your spray gun (standards: M5, M7 or 1/4"). Cheap nozzles often have casting defects that lead to uneven atomization.—>
Which nozzle to paint metallic and pearlescent
Metallics and pearls are the most capricious materials in auto repair. Their main feature is the presence aluminum or mica particles, which should lie in an even layer. If the nozzle is too large, the particles settle unevenly, and after drying dark or light spots appear ("cloud effect").
Optimal parameters for metallics:
- Nozzle size: 1.2–1.3 mm (for base layer), 1.4 mm (for varnish).
- Pressure: 2.0–2.2 bar.
- Distance to surface: 15–20 cm.
Important nuance: metallic is applied in 2–3 thin layers with interlayer drying for 5–10 minutes. If you try to cover the part in one pass, the particles will fall chaotically, and after varnishing the defects will become noticeable. For mother-of-pearl, the rules are the same, but the number of layers can be up to 4-5.
⚠️ Attention: Never use a nozzle again 1.4 mm for metallics! This will result in "spotting" that cannot be eliminated without repainting.
For varnish after metallic, a nozzle is suitable 1.4–1.5 mm. The varnish should be applied in a denser layer to “drown” the aluminum particles and give depth to the color. The pressure is increased to 2.5 bar.
Check the viscosity of the paint with a viscometer (optimally 18–22 sec at 20°C)
Spray test on a sample surface
Make sure the nozzle is clean and not clogged
Adjust the pressure according to the paint manufacturer's instructions
Prepare sufficient lighting to control layers
Nozzle for acrylic paints: nuances of choice
Acrylic paints are less demanding than metallics, but also require the right approach. Their main advantage is good hiding power, so 2-3 layers are often enough. However, if the nozzle is chosen incorrectly, the acrylic may appear “shagreen” (small ripples) or drips.
Recommendations for nozzles for acrylic:
- For base layer: 1.3–1.4 mm (pressure 2.0–2.5 bar).
- For final layer: 1.4–1.5 mm (pressure 2.5–3.0 bar).
- For local repairs: 1.0–1.2 mm (pressure 1.5–2.0 bar).
Acrylic is sensitive to viscosity. If the paint is too thick, even the right nozzle will not save you from shagreen. Optimal viscosity for acrylic - 18–22 seconds by viscometer DIN-4 at temperature 20°C. Thin the paint only with solvents recommended by the manufacturer!
When painting with acrylic it is important to observe layering technique:
1. The first coat is applied “wet on wet” with an overlap of 50%.
2. Second layer - after 5–10 minutes, overlap 70%.
3. Third (if necessary) - complete overlap.
⚠️ Attention: If after the second layer the acrylic does not cover the surface, do not increase the pressure or nozzle size! Better to apply a third coat at the same setting but with more overlap.
Nozzles for primer and putty: what you need to know
Primer and liquid putty are preparatory layers, and here the nozzle plays no less important role than when painting. The main task is to create an even base for subsequent paint application. Errors at this stage lead to defects that will appear only after the final coating.
Recommendations for nozzles for soils:
- Epoxy primers: nozzle 1.4–1.6 mm, pressure 2.5–3.0 bar. These soils are thicker and therefore require a larger diameter.
- Acrylic primers: nozzle 1.3–1.5 mm, pressure 2.0–2.5 bar. More versatile and forgiving of small mistakes.
- Liquid putty: nozzle 1.7–2.0 mm, pressure 3.0–3.5 bar. Apply a thick layer to smooth out deep scratches.
When working with soils it is important:
1. Apply criss-cross (the first layer is horizontal, the second is vertical).
2. Dry each layer according to the instructions (usually 10–15 minutes at 20°C).
3. Sand between layers with abrasive P320–P400 for acrylic primers and P240–P320 for epoxy.
For liquid putty use oval nozzle, if you work with large areas. This will help reduce time and material consumption. After applying the putty, be sure to sand with water to avoid dust and clogging of the abrasive.
Common mistakes when choosing a nozzle and how to avoid them
Even experienced painters sometimes make mistakes when choosing a nozzle. Here are the most common mistakes and how to prevent them:
- 🚫 Use one nozzle for all tasks. For example, paint metallic with a nozzle
1.5 mm, and then apply varnish with the same nozzle. Solution: have at least 2-3 nozzles in your arsenal (1.2,1.4,1.6 mm). - 🚫 Ignoring paint viscosity. Thick material will not pass through a fine nozzle, and liquid material will drip. Solution: Always check the viscosity with a viscometer.
- 🚫 Incorrect pressure. Too high pressure results in excess fog and overspray, low pressure results in uneven coverage. Solution: Follow the spray gun manufacturer's recommendations.
- 🚫 Clogged or damaged nozzle. Even micro-scratches inside the nozzle distort the torch. Solution: clean the nozzle after each use with special brushes.
- 🚫 Saving on quality. Cheap soft metal nozzles wear out quickly and produce an unstable torch. Solution: choose nozzles from trusted brands (SATA, Iwata, DeVilbiss).
Another common mistake is incorrect distance to surface. The optimal distance for most nozzles is 15–25 cm. If you hold the spray gun too close, drips will appear; too far and the paint will dry in the air, creating “dry spray” (dull spots).
To avoid mistakes, always do before painting test paint on a separate sheet of metal or cardboard. This will help to calibrate the pressure, speed of hand movement and evaluate the texture of the coating.
FAQ: Answers to frequently asked questions
Is it possible to paint a car with a 1.8 mm nozzle?
Technically it is possible, but it is not optimal. Duza 1.8 mm Designed for thick materials (for example, anti-gravel coatings or liquid putty). For paint or varnish, it will give too thick a layer, which will lead to drips and uneven texture. The exception is painting large trucks or special equipment, where coarser layers are acceptable.
How often should the nozzle be changed?
The service life of the nozzle depends on the intensity of use and care. With regular cleaning and proper use, a high-quality nozzle serves 2–3 years. Signs that it's time to replace the nozzle:
- The torch has become uneven ("tails" or bald spots appear).
- Even after cleaning, the paint does not spray evenly.
- There are scratches or corrosion on the inner surface.
Cheap nozzles can wear out within a few months.
Which nozzle is best for painting a bumper?
Bumpers are usually painted with acrylics or metallics. Optimal choice:
- For acrylic: nozzle
1.3–1.4 mm, pressure2.0–2.5 bar. - For metallic: nozzle
1.2–1.3 mm, pressure2.0–2.2 bar.
The bumper is plastic, so it is important to use plasticizer in primer and paint to avoid cracks. It is also recommended to preheat the part to 40–50°C for better adhesion.
Is it possible to use a nozzle from one spray gun on another?
Only if it matches thread type and seat size. Most professional spray guns (SATA, Iwata) have a standard thread M5 or M7, but there are exceptions. For example, some models WALCOM use non-standard nozzles. Always check compatibility before purchasing!
How to clean the nozzle after work?
Cleaning the nozzle is a critical step. Algorithm:
- Rinse the nozzle immediately after use solvent (for example, P12 or 646).
- Use soft brush (usually comes with a spray gun) to clean the internal channel.
- Blow out the nozzle with compressed air to remove any remaining solvent.
- Store nozzles in closed containerto avoid dust ingress.
Never use metal objects for cleaning - they will scratch the inside surface!