Selection of the right equipment for painting work is the foundation on which the quality of all body repairs rests. Many beginners, buying their first spray gun, often wonder: what nozzle to apply the soil on the car to avoid shaking, leaks or, conversely, too thin layer? Mistaking the diameter of a duse can cost you spoiled material, time and nerves, especially when it comes to expensive two-component compounds.
Printing is not just filling scratches, it is creating an adhesive basis for subsequent paint coating. Wrong nozzle size will lead to the fact that the material will either lie down with a "shagrene" crust due to rapid drying in flight, or give greasy flows, which then will have to be long and painfully grinded. In this article, we will break down the technical nuances that will help you choose the perfect configuration for your sprayer.
Modern soils are different: liquid acrylic, epoxy, with a high dry residue or, conversely, light one-component. For each of them. technologists develop specific requirements for the viscosity and dispersion of the torch. Understanding the physics of the spraying process will allow you not to guess, but to confidently select the tool for a specific task, whether it is local repair or complete body repainting.
Physics of the process: why the diameter of the duose matters
The principle of operation of the spray gun is based on Bernoulli’s law, where the flow of compressed air creates a vacuum, tightening the material from the tank and breaking it into tiny drops. The diameter of the duse (nozzle) here plays a critical role, as it determines the throughput of the channel. If you try to drive the thick epoxy through a too narrow hole, the spray gun will simply "spit", and the torch will be unstable.
On the other hand, using too large a hole for liquid soil will lead to overconsumption of the material and the formation of a “fog”. Small droplets, before reaching the surface, will dry out in the air, creating a roughness known as an “orange peel.” Optimal size provides balance: the drop must be small enough for smooth spreading, but large enough to fly to the detail without drying out along the way.
Use a viscometer to accurately measure the viscosity of the soil before pouring into the tank - this will give a more accurate result than the selection of dusa "by eye".
It is also important to consider the design of the spray gun needle. The needle should perfectly cover the dusa, ensuring tightness. When wearing a pair of "needle-dusa" even the correct size selection will not save the situation, as the material will start to stain inside the head of the spray gun. So, in choosing, nozzleAlways check the condition of the sealing elements of your tool.
Soil classification and equipment requirements
To understand what kind of dusa is needed for the soil, you must first determine the type of material itself. Automotive chemistry is divided into several main categories, each of which has its own density and dry matter content. Acrylic two-component filler soils (HS) are the most common and require an average hole diameter to create a full-fledged layer.
Epoxy soils used for corrosion protection often have a thicker consistency and require a more liquid dilution or, accordingly, a wider passageway. If you're working with single-component acrylic primers (e.g. for small paints), the requirements are less stringent, but pressure control remains a critical parameter.
There are also special soils, such as “liquid putty” or soils with high zinc content. These materials contain large solid particles that can get stuck in a narrow channel. Clogging the dusa In the process of work - it is always the risk of interruption of the torch and the appearance of defects on the surface. Therefore, for such materials, the choice is made towards maximum throughput.
The table below shows the main types of soils and recommended equipment parameters for them. Please note that the data may vary slightly depending on the material manufacturer, so always read the technical passport (TDS) on the bank.
| Type of soil | Recommended diameter (mm) | Pressure (Bar) | Features |
|---|---|---|---|
| Acrylic 2K (HS) | 1.6 – 1.8 | 2.0 – 2.5 | The main filler, requires good spraying |
| epoxy | 1.4 – 1.6 | 2.0 – 3.0 | Often thicker, requires careful filtration |
| Liquid putty | 2.0 – 2.5 | 3.0 – 4.0 | High viscosity, risk of blockage |
| Acid (phosphate) | 1.3 – 1.4 | 1.5 – 2.0 | It is applied with a thin layer, aggressive to seals. |
The optimal size of the duose: the golden mean
If you are looking for a universal answer to the question of how to apply the nozzle diameter soil, then for most standard acrylic fillers (2K HS) this range is the most common. 1.6. - 1.8 mm. It is this size that allows you to create a stable torch that well covers the surface and does not require excessive dilution of the material with a solvent. Too much dilution worsens the physical properties of the dried layer.
For professional workshops, where the volume of work is large, often use nozzles with a diameter of 1.8 mm and even 2.0 mm. This allows you to fill the risks from grinding faster and create a thicker layer in fewer passes. However, working with this size requires skill: you need to hold the gun strictly perpendicular and at the right distance, otherwise you need to keep it in the right position. effusion almost inevitably.
Why is 1.3 mm not suitable for soil?
Many beginners try to save and use one dusa of 1.3 mm for the base, for varnish, and for the soil. It's a mistake. After 1.3 mm, only very liquid diluted soil can be driven, which will lead to a strong shrinkage after drying. The soil should be laid down by the “body”, not a thin film.
If you own a small garage and plan to make 2-3 cars a year, buying a separate 1.8mm duo gun may seem like a redundancy. In this case, you can consider the scalp with replaceable (combi kits), where the set are duces 1.3, 1.4 and 1.6 mm. Dyuz 1.6 mm will be a compromise option, allowing you to work with liquid soils, and with a dense base.
Pressure adjustment and application technique
Even a perfectly selected nozzle will not save the situation if the air pressure is incorrectly exposed. For soils of HS type, the pressure at the outlet of the duse in the region of 2.0 - 2.5 bar is considered optimal. Many masters measure the pressure on the compressor pressure gauge, which is a mistake, since losses occur in the hose. It must be used gauge-gaugeinstalled directly on the handle of the spray gun or at the entrance to it.
The application technique also affects the choice of duo size. When working with a large nozzle (1.8 mm), the movements should be faster and clearer. The overlap of the strips (torches) should be approximately 50-60%. If you drive too slowly, the ground will flow; if too fast, there will be a “dry” shavern that cannot be properly traversed.
- 🎨 First layer (wet) is applied in rapid movements to create a clutch base.
- 🌫️ Second layer (main) lies more slowly and fatter, covering the risks.
- 💧 Third layer (control) can be applied with the addition of a solvent for better spreadability.
⚠️ Attention: When working with large diameters of dusa (1.8 mm and above), be sure to use a respirator with quality filters. The volume of sprayed material is large, and the concentration of harmful vapors in the garage air increases instantly, creating a risk of poisoning.
It is also important to control the distance to the surface. For soils with a large duse, it is 15-20 cm. If you zoom in closer, the center of the torch will “squeeze” the fresh layer, creating craters. If you move away, the material will start to dry in flight, and you will get a rough surface that will have to be grinded for a long time.
☑️ Pre-primary inspection
Problems with the wrong choice of nozzle
Ignoring the recommendations for choosing a diameter leads to specific defects, the elimination of which requires additional costs. If you used too small a nozzle for thick soil, you will encounter the effect of "spitting." Large droplets will fly out of the duse, leaving craters on the surface, which will appear after painting. Squeeze such soil through a narrow hole can only be greatly increased pressure, which will increase fog formation.
The use of too large a nozzle for liquid soil is fraught with overconsumption of material. You literally "plug" the part, creating a thick layer that will dry for a very long time and can wrinkle. Besides, superheat in the head of the spray gun due to friction against the wall of a wide duse at high pressure can reduce the life of the mixture (pot life).
Frequent problems are also the problem of clogging. In the soils can come across undissolved particles of pigment or clots. At duze 1.3mm, they will get stuck instantly, forcing you to interrupt work for flushing. At duze 1.8mm, they are likely to pass freely. Therefore, for dirty or long standing materials, it is better to choose magnified.
⚠️ Attention: Never clean the dusa with metal objects (needles, wire). This scratches the inner walls, disrupting the torch's geometry. Use only special brushes and washing liquid.
Another hidden defect is uneven shrinkage. If the soil was heavily diluted to pass through a small duse, the percentage of dry residue in it decreases. After drying, this layer will subside more, and through the lacquer coating, risks from the sandpaper that you have so carefully hidden can manifest.
Equipment care and durability of the duza
The life of your duo depends on how you take care of it. Acrylic soils, solidifying, turn into stone. If you leave even a microscopic amount of material inside the nozzle, the next use it can break off and spoil the coating. Immediately after work, wash the gun with the right one. solvent (646, 499 or specialized).
When assembling and disassembling the head of the spray gun, be careful. Duza is a precision detail, often made of brass or stainless steel. A hit or fall can warp it and the torch will become oblique. When replacing the nozzle, use only the keys from the kit, avoiding excessive effort that can break the thread.
Properly selected dusa (1.6-1.8 mm for acrylic) + purity of the tool = no defects and saving time on grinding.
Check your sealing rings regularly. If they are worn out, the air will be sucked into the tank or, conversely, the material will etching out. This violates the stability of the torch, making it impossible to properly prime, regardless of whether the torch is stable. duusage You chose. Timely replacement of the remplekt is cheaper than buying a new spray gun.
Frequently Asked Questions (FAQ)
Can I apply the soil with a nozzle of 1.4 mm?
Technically possible, the soil is very liquid (e.g., some types of epoxy or acid soil) and well filtered. However, for standard acrylic fillers (HS), the 1.4 mm duse will require strong dilution, which will worsen the coverability and increase the shrinkage of the layer. It is better to use 1.6-1.8 mm.
What pressure should I put on the ground?
The optimum pressure at the exit from the dusa (on the pistol) is 2.0-2.5 bar for acrylic soils. The pressure on the compressor pressure gauge will be higher (usually 3.5-4.5 bar) due to losses in the hose. Always look for the exact values in the technical map of the material.
Why does the soil lie down with a shaking (orange peel)?
There may be several reasons: too long a distance to the part, high air pressure, rapid movement of the hand or too viscous soil for the selected diameter of the duse. It is also possible to use a quick solvent at high temperature in the paint chamber.
Do I need to dilute the soil for the spray gun?
Yes, almost all soils require the addition of hardener and solvent. Mixing ratios (e.g. 4:1:10%) are strictly regulated by the manufacturer. Violation of proportions will change the viscosity, and even the right nozzle will not help to get a quality torch.
What is the difference between dusa for base and dusa for soil?
The base duse (metallic) is usually smaller (1.3–1.4 mm) to create fine mist and evenly distribute pigment particles. The duze for the soil is larger (1.6-1.8 mm) to allow a more viscous material to pass through and create a thick layer without overspending time. Using a base in a primer gun is possible, but not vice versa.