Ready,set,go!

For any painter, the daily routine of disassembling and assembling their spray gun – including the removal and refit of the nozzle set – makes it an extremely familiar task. Doing it properly is the basis for looking after your spray gun so that it will look after you, in terms of delivering ease of use and peak performance, while minimising application issues that lead to frustrating rework. However, despite how common this task is, there are a few practical SATAjet X 5500 maintenance tips you may not be aware of. Incorporating them will help extend the lifetime of a nozzle set to the max.

Everyday wear

A nozzle set primarily wears out due to paint material passing through the components i.e. the fluid tip and the paint needle. As it flows, paint material causes friction on the fluid tip and the paint needle. Although we are talking about a relatively soft liquid flowing over hard metal components, when this happens for long enough and at a high enough velocity, wear and tear slowly starts to alter the precisely designed shapes. The actual amount of wear varies with the type of material and its composition, as well as with the usage.

Sequence of disassembly and assembly

Properly cleaning your spray gun requires the disassembly of the nozzle set and it’s here that it’s particularly important to ensure that the paint needle has been removed prior to unscrewing the fluid tip. If this is not done, the fluid tip and the paint needle will rub against each other due to the rotation, thus causing ‘artificial’ wear and tear.

Fluid tip durability

In order to prevent air from entering the material channel where it creates a ‘fluttering’ spray pattern, the fluid tip must be handtightened to achieve a proper seal function. This corresponds to approximately 11 to 14 Nm in the case of SATAjet spray guns and 12 Nm in the case of minijet spray guns. With the SATAjet X 5500, the fluid tip is sealed by means of the attached fluid tip seal, whereas all other SATA spray guns are sealed via the air distribution insert.

If excessive tightening torque is used, the fluid tip seal and / or the air distribution insert can be squeezed, resulting in a permanent dimension reduction (i.e. making it shorter or thinner). Due to the gap created between the spray gun body and the seal element, air will be able to stream from the air passages into the material channel, eventually leading to the formation of bubbles inside the vented cup. As a consequence, the fluid tip will alternatingly release material followed by air causing an intermittent material flow (effectively a fluttering spray pattern) which can result in an imperfect finish and possible rework.

Important note: Dried material residues or other types of contamination in the area of the material channel or on the nozzle components can also affect the spray fan pattern. With this in mind, it’s recommended that you first check whether the spray gun and, in particular, the nozzle set have been thoroughly cleaned. Should a faulty spray pattern persist, you must replace the defective seal.

Why always replace the complete SATA nozzle set?

Each nozzle set consists of three individual components – a paint needle, fluid tip and air cap. At the completion of each SATA production process, all three of these components are tested for their manufacturing accuracy and quality. On top of this, all components then have to pass a final, comprehensive manual quality check as a complete nozzle kit. Only then can they leave the factory, either mounted in a new gun or as a replacement nozzle set. This ensures the spray fan pattern (height / width / shape), as well as the atomisation, meets the high SATA standards. If one of the three elements falls outside the defined tolerance range, that nozzle set will not produce the optimum spray pattern required. In practical terms, this results in negative effects, such as mottling or colour shade deviations when applying basecoat, increased paint material consumption or poor clearcoat distribution (orange peel). Rework resulting from a worn nozzle set is not only frustrating and time consuming, it also causes considerable disruption to shop workflow.

As mentioned above, each nozzle set is subject to gradual wear and tear which cannot be detected by the naked eye.

To actually determine which component is most affected would require specialist measuring equipment and replacing just one part of the nozzle set will not result in the same box-fresh, SATA spray pattern as found in a brand new gun. This is why SATA recommends the regular replacement of the complete nozzle set (between around six months and one year, depending on the actual usage) to ensure you continue to benefit from the precise, market leading spray pattern you invested in when you bought your SATA gun. R