Modern paint spray guns may not differ much from each other at first glance. However, they do vary in terms of their design. Because just the important core piece, namely the nozzle set, is different in size. There is a reason for this, which will be described in the following sections.
It will also be shown which spray pattern a worn nozzle set produces, which nozzle sets might be the best, and which jobs they are suitable for.
Why is the proper nozzle so important?
You should select the proper nozzle for your paint spray gun, as they are differently suited for the respective paints, such as clear and base coats, primers, or glazes. Because with the correct nozzle, you can apply a correspondingly opaque, delicate, and, above all, even coat.
On the other hand, the proper nozzle protects you from clogging or a foggy spray pattern. With an unsuitable nozzle, you will have to clean your spray gun more often.
If you use the proper nozzle for the appropriate viscosity of the paint material, this will usually not happen. If necessary, paints and varnishes can also be thinned.
Effects of a worn nozzle set on the painting result
A worn nozzle set can cause various problems. The spray pattern becomes irregular and stands out from the otherwise rounded paint pattern.
You will then see a mixed form of regular and intense paint mist and at least but -application. Or the gun may even “leak” or speckle, with larger paint droplets coming out.
In most cases, however, it shows a lateral or even curved focus during application instead of predominantly generating a round color image. In the center, the nozzle applies the color too intensively instead, and on the or even only one side, it sprays widely.
It is recommended that you first think of a blockage and clean the nozzle set thoroughly. This may also be the cause of the abnormalities. Check the scene with a high magnification loupe to detect defects and cracks correctly.
The right nozzle system for the spray gun
Different nozzle systems are primarily matched to the liquid materials and their viscosity. Of course, you can also increase the air pressure a little more, such as creating a more delicate spray mist.
However, it would help if you remained within the selection range recommended by the manufacturer in the technical data sheet or described below.
You will find a 0.5mm nozzle for very liquid, mostly water-soluble paints with finer pigments in the entry area. The largest area in the “normal painting area” has a 2.5mm nozzle.
Which nozzle system is the best?
An optimum nozzle system would be one that would perhaps give the best result for all types of spray materials. However, there is no simple average in the form because you have to adjust the nozzle systems in each case and match them to the paints and primers to be used.
This is due to the viscosity of the respective fluids. The following are guidelines for the paints and nozzle sizes unless otherwise stated in the manufacturer’s technical datasheet:
- Automotive paints: 0.8 to 2.5 mm nozzle (on thick fluid).
- Low-viscosity primers and basecoats: 1.2 to 1.3 mm nozzle
- Transparent lacquers and 2K-Unilacke: 1.3 to 1.4 mm nozzle
- Primers and fillers: 1.6 to 1.8 mm nozzle
- Spray filler: nozzle with 2.0 to 2.5 mm
Therefore, the spray filler is at the outer end, which is possible with conventional paint guns and the specified nozzle size. Otherwise, this material is already the transition to airless spray guns.
On the other hand, a larger nozzle is always responsible because the layer thickness per spray pass is considerably greater. The spray filler is also the showcase model here.
On the other hand, a smaller nozzle saves material and usually a thinner layer, as less material can flow through it.
When should you change the nozzle of the spray gun?
It would help if you changed the nozzle when the spray pattern and behavior have changed, and you cannot restore it by thorough cleaning. This is often given the background that the nozzle and needle are worn or even completely broken.
If the gun has been stored for a long time without being cleaned or cleaned with the wrong solvent, a change is also recommended. It has then certainly been affected.
Should you buy individual nozzle parts or a nozzle set?
You must always buy the complete set. This includes the nozzle, needle, and air cap. This is because often, several components are damaged or have affected the other part in some way.
Depending on the supplier, the set forms a sales unit, which you get together much more accessible. In addition, they are matched to each other, and you are then guaranteed that all components are in an original and therefore top condition.