The wear and tear of Airless nozzles is often times underestimated because most users are unaware of the negative effects of worn nozzles. “The nozzle is still working”, we hear from many customers who come to our service centre with their paint spraying equipment. Often this is unfortunately not the case, because the majority of users change the nozzles too late. But when should a paint spray nozzle be replaced to avoid negative effects such as disturbances in the spray pattern, higher paint consumption and/or too much overspray?
Video coming soon
What factors are responsible for the wear and tear of an Airless paint spray nozzle?
Various factors affect the life of Airless nozzles. Here are the key points at a glance:
- Solid particles in the paint or material
- Pressure with which the paint is sprayed
- Care of the nozzles
The solid particles in the paint or material is a burden on the nozzle because the particles in the paint flow past the nozzle orifice under pressure. In this way they cause abrasion at the nozzle opening over time. The higher the solids content in the paint, the shorter the life span of the nozzle. Materials containing minerals such as silicate or lime paints thus produce a higher level of wear on Airless nozzles compared to other materials.
The spraying pressure also plays a role in the wear of an Airless nozzle. Higher pressure means a higher workload for the sprayer and also for the spray tip. The pressure also increases the wear on the nozzle opening and leads to a shorter life.
The care of the nozzles prevents the paint and residual material from drying. In the absence of care and maintenance, paint can clog the nozzle channel and make the airless nozzle unusable.
How does wear on Airless spray nozzles affect the spray pattern?
Airless nozzles are usually made of extra hard tungsten carbide. Nevertheless, paint and pressure over time wear down the nozzle. During manufacturing, a nozzle orifice is ground into the nozzle to determine the flow rate of paint and the jet width. Wear of the nozzle changes the ground shape of the nozzle opening and thus also the spray pattern. On the left in the diagram, a spray pattern with an even color distribution over the entire spray area of a new nozzle can be seen. Right next to it, the gradual wear of the nozzle is shown. The abrasion increases the nozzle opening. The spray jet becomes more uneven and smaller, although the nozzle opening increases.
As a result, more paint is applied to a smaller area. The spray pattern and the paint distribution become more uneven. The risk of paint runs increases. It can lead to higher overspray. In addition, significantly more material is consumed. By reducing the orifice width, a greater amount of time has to be calculated and the working speed is reduced compared to simply using a new nozzle.
Negative effects when using worn nozzles summarized:
- Disturbances in the spray pattern (paint runs, banding)
- uneven paint distribution
- increased overspray
- significantly higher material consumption
- reduced orifice width – higher time spent spraying surfaces
To avoid these negative effects, nozzles should be replaced in a timely manner. The majority of users use nozzles for much longer than their intended use period. The costs caused by higher paint consumption, higher time expenditure and lower quality of the work result usually exceed the purchase of a new nozzle many times over.
Nozzles Tip: Replacing nozzles in good time saves money through less paint consumption, less overspray, higher working speed and better surface quality.
When should airless nozzles be replaced?
There is no rule of thumb, even from the manufacturers, there is little information about it. The solids content varies from paint to paint, and the pressure setting also varies from user to user. The wear point for classic emulsion paint is from our experience about 300 to 500 liters. In the case of paints with higher solids content, the useful life may also be significantly reduced again. For mineral paints such as silicate paint should be expected from a shorter service life than emulsion paints. In extremely abrasive paints with zinc or mica iron, the life span is significantly reduced again and is in these cases sometimes less than 100 liters.
Compare the used Airless nozzle spray pattern with the spray pattern of a new spray tip
The nozzle wear takes place in sections, so that the spray pattern slowly but steadily deteriorates. If you work infrequently with a sprayer, many users are not even aware that the beam width has already been significantly reduced, the spray pattern is no longer optimal and paint is wasted. A new nozzle as a reference can help here. If one is unsure, one can compare the spray pattern of the used nozzle with the spray jet of a new one. Of course, these should be the same nozzle sizes of the manufacturer / nozzle type etc.
Routine when changing the spray nozzle
Some of our customers change nozzles for each new project and include a new nozzle in their pricing calculations. If the projects are large enough, this approach can make sense, because the user is on the safe side. For larger projects, however, you may need to use multiple nozzles.
Always spray high-quality projects with a new airless nozzle
Another starting point is to decide on the quality requirements of a project. Recently a customer told me that he always uses new nozzles for higher quality objects to get the best possible result. If the nozzles are then used, they are used for priming or for objects that are not in the design area (basement, underground car park). But even here, the nozzles should not be used too long, because the higher paint consumption of a worn nozzle quickly exceeds the value of a new nozzle.
Keep an eye on changes in the spray jet pattern
It is best to keep an eye on the spray pattern and to see clear changes if the nozzle is replaced (see graphic above). As a beginner you should also consider the paint consumption and the stated value of 300 to 500 litres of paint used per nozzle. This helps as a guideline until you gain experience working with the material and spray tips.
What can be done to increase the life of Airless spray nozzles?
Sooner or later the nozzle will have to be replaced, but there are a few things to consider to extend the life span of an Airless nozzle.
Spray with low pressure
If the pressure setting of the airless device is selected as low as possible, the load and the wear for the airless nozzle are also significantly lower. Therefore: as much pressure as necessary needed to spray the paint sufficiently and evenly, but not more. The positive side effect, inject with less pressure also reduces the formation of overspray. You also have available from the manufacturers Wagner (HEA nozzles) and Graco (FF LP and LP nozzles) nozzle systems which provide good atomization with less pressure. These nozzle systems can help to increase the life span of nozzles.
- Graco RAC X FF LP Nozzle – order directly – click here
- Graco RAC X LP Nozzle – order directly – click here
- Wagner HEA ProTip – order directly – click here
Clean Airless nozzles properly
If nozzles are not cleaned properly, paint may dry up and clog the spray tip orifice. Not always can these blockages be loosened and removed. Then the nozzle becomes unusable. There are systems for nozzle cleaning in egg-timer form of the manufacturers Wagner and FARBMAX. This preserves the nozzles, prevents paint residues from drying out, and protects the nozzles better.
- Wagner TipClean Nozzle Cleaner – order directly – click here
- FARBMAX Nozzle Cleaner – order directly – click here
Select, clean and replace the gun filter to match the nozzle
Pistol filters in the grip of a paint spray gun protect the nozzle from blockages, contamination and damage. Therefore, the appropriate filter should be selected for the nozzle, not too coarse and not too fine. Only in this way can the optimal filter effect arise. The spray nozzle is protected against blockages. The gun filter should be cleaned regularly and replaced if necessary.
- Overview of all available gun filters – click here
Store spare nozzles and re-order in time
The consumption of airless nozzles and filters are mandatory and predictable. Nevertheless, every day we see customers having to stop work because they have no spare nozzles on the job site. We store all common nozzle types and nozzle sizes of the manufacturers Wagner and Graco and are committed delivering these goods to you as quickly as possible. Standstill on the construction site can be avoided if nozzles and accessories are ordered on time and on schedule. Here is an overview of the most common nozzle models:
- Graco RAC X (blue) – order directly – click here
- Graco RAC X (brown) – order now – click here
- Graco RAC X FF LP (green) – order directly – click here
- Graco RAC X LP (green) – order now – click here
- Graco XHD (gray) – order directly – click here
- Graco RAC V (black) – order directly – click here
- Graco RAC V Linelazer Nozzle – order directly – click here
An overview and an explanation of the function and use of the various Graco Airless nozzles, we have summarized for you in the video contribution Graco Airless Nozzles – Overview of RAC X to FF LP & XHD (video coming soon).
The manufacturer Wagner also offers various nozzle models to choose from:
- Wagner TradeTip 3 (yellow) – order directly – click here
- Wagner TradeTip 3 FineFinish (purple) – order directly – click here
- Wagner HEA ProTip nozzle (green) – order directly – click here
A video explaining the application area of the various nozzles can be found on our Youtube channel entitled Wagner Airless Nozzles – Overview from TradeTip 3 to HEA (video coming soon).
For any further questions or if you would like to get your hands on one of these products seen in this article, you can contact us on +49 (0) 30 220 15436, fill out our contact form below or email us. If you wish to purchase one of the products mentioned above, you can check them out in our online store. You can also visit us at our service base during office hours.