Choosing the right nozzle for applying varnish to a car is 50% of the success in achieving perfect gloss and durability of the coating. Even the highest quality varnish Sikkens, PPG or Mobihel will show poor results if sprayed through the wrong nozzle. Mistakes at this stage lead to defects: from “orange peel” to uneven shine, which will then have to be eliminated by polishing or repainting.
In this article we will figure out how to choose a nozzle for a specific type of varnish (HS, MS, UHS), equipment (HVLP, LVLP, RP) and tasks (base coat, top coat, local repair). You will learn why professionals use different sizes for acrylic and polyurethane varnish, how the nozzle material affects the quality of the spray, and what critical errors beginners admit when choosing. We also tested 5 popular nozzles from DeVilbiss, Iwata and SATA - comparison results in the table below.
Why nozzle size is important for varnish
The nozzle diameter determines material viscosity, which it is capable of atomizing efficiently. For varnish, it is critical to maintain a balance: a nozzle that is too small will create excess pressure, which will lead to “dry” spray and loss of gloss. Too large - it will give coarse drops that will not have time to spread, forming shagreen.
Varnish manufacturers always indicate the recommended nozzle size on the can. For example:
- 🔹 HS varnishes (high-hardness): 1.3–1.5 mm - due to high viscosity, they require a larger pass.
- 🔹 MS varnishes (medium hardness): 1.2–1.4 mm - a universal option for most jobs.
- 🔹 UHS varnishes (ultra-high hardness): 1.4–1.7 mm - maximum throughput required.
Key nuance: the nozzle size for varnish should be 0.1–0.2 mm larger than for base paint from the same manufacturer. This is due to the fact that varnish is usually applied in a thicker layer and contains more solvents, which evaporate more slowly.
Nozzle types: materials and their effect on atomization
The nozzle material directly affects wear and tear, torch quality and solvent compatibility. Let's look at three main types:
| Material | Benefits | Disadvantages | Recommendations |
|---|---|---|---|
| Stainless steel | Durability, resistance to aggressive solvents | More expensive than aluminum, may “stick” if polished poorly | For professional use with UHS varnishes |
| Aluminum | Lightweight, cheap, heats up quickly | Soft - wears out in 2–3 months of intensive work | For amateur painting with MS varnishes |
| Ceramics | Perfectly smooth surface, non-corrosive | Fragile, afraid of mechanical shocks | For working with metallics and pearls |
| Teflon coating | Non-stick effect, easy to clean | Expensive, coating wears off over time | For varnishes with high solids content |
🔧 Practical advice: If you are working with 2K varnishes (two-component), give preference to stainless steel or Teflon. These materials do not react with hardeners, unlike aluminum, which can oxidize.
Before using a new nozzle for the first time, wash it with solvent. 646 or 647 - this will remove factory grease, which can ruin the first layer of varnish.
Nozzle compatibility with spray gun type
Not every nozzle will fit your spray gun. It is important to consider here air supply system and spray head type:
- 🔫 HVLP (High Volume Low Pressure): requires a nozzle with a smaller diameter (1.0–1.4 mm), as it operates at low pressure. Ideal for varnishes MS and HS.
- 🔫 LVLP (Low Volume Low Pressure): universal, suitable for nozzles 1.2–1.6 mm. Optimal for UHS varnishes.
- 🔫 RP (Reduced Pressure): 1.3–1.8 mm nozzles are required due to high air consumption. Most often used in industrial settings.
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Attention: If you use a nozzle larger than the recommended size for your spray gun, you risk getting "cobwebs" (thin strands of varnish) due to insufficient outlet pressure. For example, a 1.7mm nozzle in an HVLP gun will result in uneven spray.
Manufacturers of spray guns often produce “original” nozzles optimized for a specific model. For example, for SATAjet 5000 better to use nozzles SATA Nozzle with Teflon coating, and for DeVilbiss GTI Pro Lite — original steel nozzles of the series DV1.
Top 5 nozzles for auto varnish: comparison and tests
We tested 5 popular nozzles for spray uniformity, wear resistance and compatibility with different varnishes. Tests were carried out on spray guns Iwata W-400 (LVLP) and DeVilbiss FLG-5 (HVLP) with varnishes PPG D8115 (HS) and Mobihel 2K (MS).
| Nozzle model | Material | Size(mm) | Spray rating (1–5) | Price (₽) |
|---|---|---|---|---|
| SATA Nozzle 1.4 | Stainless steel + Teflon | 1.4 | 5 | 3 200 |
| DeVilbiss DV1 1.3 | Aluminum (anodized) | 1.3 | 4 | 1 800 |
| Iwata LPH-400 1.5 | Ceramics | 1.5 | 5 | 4 500 |
| Waldom 1.2 | Stainless steel | 1.2 | 3 | 900 |
| Anest Iwata 1.6 | Teflon | 1.6 | 4 | 3 800 |
💡 Conclusion: Showed the best price-quality ratio DeVilbiss DV1 1.3 — it is suitable for 80% of amateur painting tasks. For professionals working with UHS varnishes, optimal SATA Nozzle 1.4 or Anest Iwata 1.6.
Check the recommended size on the varnish can|
Check compatibility with your spray gun (HVLP/LVLP/RP)|
Select material: stainless steel for 2K varnishes, aluminum for budget work|
Buy a replacement needle from the same manufacturer|
Test the nozzle on a sample piece before the main work -->
Common mistakes when choosing a nozzle
Even experienced painters sometimes make mistakes when choosing a nozzle. Here are the most common mistakes and their consequences:
- 🚫 Using a nozzle from the base paint for varnish.
Result: the varnish applies too thinly and does not provide sufficient protection. For example, if you painted the base with a 1.2 mm nozzle, you need at least 1.3–1.4 mm for the varnish.
- 🚫 Saving on nozzle material.
Aluminum nozzles are cheaper, but their surface quickly becomes covered with micro-scratches, which leads to fish-eye (irregularities in the varnish).
- 🚫 Ignoring air pressure.
A 1.5 mm nozzle in an HVLP gun will require an increase in pressure to 2.5–3 bar, otherwise the varnish will “spit.”
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Attention: If after applying varnish with a 1.3 mm nozzle you see “shagreen” (small tubercles), this means that the varnish is too viscous for this size. Dilute it 5–10% with solvent R-12 or switch to a 1.4–1.5 mm nozzle.
🔍 How to check if your choice is correct? Apply a test coat to cardboard or an old piece. An ideal spray looks like a uniform “mist” without drops or bald spots. If you see “tails” (elongated drops), the pressure is too high or the nozzle is too large.
How to care for a nozzle so that it lasts longer
The service life of a nozzle depends not only on the material, but also on care. Follow these rules:
- 🧼 Cleaning after each use: wash the nozzle with solvent
646or a special cleaner PPG DX330. Use a soft brush (not metal!). - 🛠 Storage: Remove the nozzle from the spray gun and store it in a plastic case. This will prevent corrosion and mechanical damage.
- 🔄 Needle replacement: the needle and nozzle must be from the same manufacturer. For example, a needle SATA in the nozzle DeVilbiss will lead to uneven spray.
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Attention: Never use nozzles for cleaning acetone or white spirit — they destroy the Teflon coating and corrode aluminum. Suitable for ultra-fast cleaning Cleaner 3800 from 3M.
💰 Economic advice: If you paint 1-2 cars per month, it is enough to have 2 nozzles: 1.3 mm for base/varnish MS and 1.5 mm for HS/UHS. For professional workshops, we recommend a set of 3–4 nozzles with a pitch of 0.1 mm (1.2, 1.3, 1.4, 1.5).
What to do if the nozzle becomes clogged during operation?
1. Immediately stop spraying and remove the nozzle from the gun.
2. Immerse it in solvent 647 for 5–10 minutes.
3. Blow with compressed air (pressure no more than 2 bar!).
4. If the needle hole is clogged, carefully clean it with a wooden toothpick (not metal!).
5. Test on a sample surface before continuing.
FAQ: Frequently asked questions about varnish nozzles
Is it possible to use one nozzle for base and varnish?
Technically possible, but not recommended. Varnish usually has a high viscosity, so the nozzle for it should be 0.1–0.2 mm wider. For example, if you painted the base with a 1.2 mm nozzle, it is better to use 1.3–1.4 mm for varnish. This will ensure even coverage without dry spray.
What size nozzle is needed for varnish PPG D8115 (HS)?
The manufacturer recommends 1.4–1.5 mm. For an HVLP spray gun, 1.4 mm is optimal at a pressure of 2.0–2.2 bar. If you use LVLP, you can take 1.5 mm. Important: PPG D8115 sensitive to humidity - check the climatic conditions before application (optimally: temperature 20–25°C, humidity up to 60%).
What are the differences between nozzles? SATA and DeVilbiss?
Main differences:
- 🔹 SATA uses Teflon coating, which reduces wear and improves the glide of the varnish.
- 🔹 DeVilbiss offers anodized aluminum nozzles - they are cheaper, but less durable.
- 🔹 Torch geometry: y SATA softer spray edges, DeVilbiss - clear.
Preferable for professional work SATA, for amateur - DeVilbiss.
Why does the varnish turn out matte after spraying with a 1.3 mm nozzle?
There may be several reasons:
- Too high air pressure (more than 2.5 bar) - the varnish “dries” in flight.
- Insufficient amount of hardener in the varnish (check mixing proportions).
- The nozzle or needle is dirty (needs cleaning).
- Low room temperature (less than 18°C) - the varnish does not have time to spread.
Try reducing the pressure to 1.8–2.0 bar and apply another coat.
Can the nozzle be polished to restore smoothness?
You can polish, but with caution:
- 🔹 For stainless steel use paste GOI (green) and a felt circle.
- 🔹 Polish aluminum only with a soft cloth and paste. Autosol.
- 🔹 Ceramics and Teflon cannot be polished - this will ruin the coating.
After polishing, be sure to check the nozzle on a test surface: changing the geometry of the hole can lead to an asymmetrical spray pattern.
The correct nozzle is 50% of success in painting. Always test a new size on a sample piece and monitor the air pressure. Savings on nozzle quality will result in additional costs for polishing or repainting.