Low-fog Spray Technology: Dare To Grab The Gun

Spraying is efficient and delivers first-class surfaces. Low-fog technologies enable spray application even indoors and make it profitable in smaller areas. Malerblatt has tested a low-fog spray technology - and is wondering why they no longer use painting companies.

Author / Photos: Susanne Sachsenmaier-Wahl

Perhaps you've painted a cassette door recently. Or coated with a lamella shutter or a wooden ceiling. Perhaps you still remember what a time-consuming endeavor that was. At least if you used a classic brush and roller. But you probably didn't consider spray painting. "In Germany, painting work is only about 20 percent carried out using the spray process," says master painter Yannick Heil, technical product manager at Caparol. It is difficult to explain why, especially since the picture in other countries is completely different. "In the United States, for example, the ratio of spray painting to hand painting is exactly the opposite, with 80 percent spraying there," says Heil.

Especially in the case of renovation, on site at the construction site, sprayers are used here sporadically. For some years now, low-fog spraying methods have been available, which, according to the manufacturer, make spraying possible even indoors, since the overspray is minimal. Door sticks, wooden ceilings, banisters or built-in wardrobes can be coated efficiently and with high quality - without great covering effort. But door leaves or shutters could also be conveniently painted on site, and there was no need to transport them to the workshop.

Where do the reservations come from?

So why do German painters have such great reservations about spray technology? Is it only because you are not as in love with technology in Germany as across the pond? Or does the spraying technology ultimately do no better than hand painting in terms of time and quality of results? Is the handling of the spraying equipment too complicated? Are the acquisition costs for a corresponding sprayer too high? Is the cleaning too complex? Or does everything ultimately fail due to the spray mist?

I asked myself these questions when I dealt with the "machine-assisted lack of pain" of the local painters. Whenever I want to know exactly, I dare to try it myself. So I made an appointment with Caparol to take a close look at the “NAST” technology, the low-fog, high-tech technology from the paint manufacturer. First of all: My requirements as a master painter, who has not been “on the wall” for years, but mostly guards the desk instead, are certainly far behind those that every “active” painter brings.

Perfectly coordinated

The abbreviation "NAST" simply stands for low-fog spray technology. Because the spray mist reduction was the decisive criterion for Caparol when the NAST process was developed. Yannick Heil remembers: “When looking for a spray gun that could be used to paint with little fog, we came across Wagner's“Finish Control 5000”low-pressure device. The device appealed to us spontaneously, but the overspray was still too high for us. “So they worked with Wagner to optimize the nozzle and thus reduce the overspray. The front-end nozzle specially developed for the NAST system ensures a particularly uniform, fine spray pattern. "The results improved significantly, but we were still not completely satisfied," says Heil looking back at the NAST story.“After all, it was clear to us that we had to match our coating materials to the process,” summarizes the master painter.

Caparol now offers three NAST coating materials: an adhesive primer and two PU lacquers (matt and satin gloss). All three products are water-based, because the system should also be used indoors, and water-based paints have now established themselves as the standard. The NAST paints are a further development of existing standard products. The suffix NAST indicates the special spray quality on the label. Bernhard Linck, an expert in paints and their application, explains: “NAST paints have a special structural viscosity that is precisely matched to the aerodynamic conditions at the nozzle outlet. In contrast to a universal paint, which is set for brush, roller and spray processing, this means: The NAST paint has the property when spraying,not to be torn into millions of tiny paint particles that fly past the object as a so-called overspray or bounce back from it. The NAST paint is better held together in the air flow and transported to the surface, so it arrives almost loss-free where it should go - on the surface to be coated.”The paints are adjusted to the appropriate viscosity in the factory and therefore must not be thinned. Yannick Heil: "Otherwise there would be an undesirable overspray again." Because of the special viscosity, the paints are also not suitable for processing with a brush or roller. The standard quality should be used for this. The NAST paint is better held together in the air flow and transported to the surface, so it arrives almost loss-free where it should go - on the surface to be coated.”The paints are adjusted to the appropriate viscosity in the factory and therefore must not be thinned. Yannick Heil: "Otherwise there would be an undesirable overspray again." Because of the special viscosity, the paints are also not suitable for processing with a brush or roller. The standard quality should be used for this. The NAST paint is better held together in the air flow and transported to the surface, so it arrives almost loss-free where it should go - on the surface to be coated.”The paints are adjusted to the appropriate viscosity in the factory and therefore must not be thinned. Yannick Heil: "Otherwise there would be an undesirable overspray again." Because of the special viscosity, the paints are also not suitable for processing with a brush or roller. The standard quality should be used for this.“Because of the special viscosity, the paints are also not suitable for processing with a brush or roller. The standard quality should be used for this.“Because of the special viscosity, the paints are also not suitable for processing with a brush or roller. The standard quality should be used for this.

Of course, the three NAST products are not suitable for all applications. The sprayer can also be used to apply other materials, but Heil advises that only water-borne paints be used and makes it clear: "The spray mist will always be higher with other products."

Spray instead of painting or rolling

Before I can test the low-fog spray process, Yannick Heil gives me a brief introduction and explains how the device should be set, because the correct setting of air and material quantity is crucial for atomization and paint mist formation. The low pressure device works with a pressure of approximately 0.2 bar. The special NAST products should be sprayed with about 2/3 of the air volume. This corresponds to setting 7–8 on the air regulation of the device. The material quantity regulation should also be set to about 8. In contrast to airless spraying, the recommended spraying distance to the workpiece with NAST technology is only around ten centimeters. The speed at which the gun is moved over the object to be painted should also be slower than with airless spraying. As water-based paints tend to attract relatively quickly, Caparol does not recommend painting in the cloister as usual, but instead in strips that are half overlapped.

Low-fog spray technology: Test passed with flying colors

Lined up with lots of information, it is finally time to go: Packed in a truly "figure-flattering" paint suit and equipped with a respirator mask, I can grab the pistol. For the spray gun with the NAST front end, of course. I have never had such a device in my hand before. Nevertheless, Yannick Heil asks me to repaint a slatted shutter from blue to red. If that goes well …

When I finally take the pistol in my hand, I stop short. Compared to an airless gun, the NAST gun is initially somewhat heavy and unwieldy, which is not least due to the suction cup, which has a capacity of one liter.

I am immediately positively surprised by the painting process. The spray jet can be used very specifically. With the help of an omnidirectional jet, I first coat the transition area between the frame and the slats. Then I choose the vertical flat jet. By moving the pistol slowly, which is somewhat unusual at first, the paths can be drawn very precisely and the recommended overlap of half a path can be reliably implemented. But above all the plus points are the result: Due to the relatively high layer thickness that can be achieved with the process, I only see red after painting. The blue background of the shutter is completely covered, including the rounded slats. At the same time, there are no runners to be found anywhere, which is quite an achievement with a louvre shutter. The paint surface is also wonderfully smooth.

Minimal spray mist

Following my self-test of shutters, Yannick Heil demonstrates how easy and high-quality it is to coat a panel door with the NAST system. In this case, he chooses vertical spray tracks. When asked why, he replied: “The spray mist is distributed around the edges of the door leaf. However, the aim of spray technology is to keep the overspray as low as possible. With vertical coating, there are fewer areas in which the workpiece is sprayed over, which automatically reduces the spray mist.”This is very small anyway. On the cover paper behind the door leaf, it is reflected to a maximum of 15 to 20 centimeters outside the workpiece.

While I'm still amazed at how easily the profiles of the infill door can be revised in just one work step (a separate application with varnish as with hand painting is not necessary), Yannick Heil gives me other practical tips such as these: under no circumstances try to improve the drying phase. “The material attracts extremely quickly, which is why the surface can no longer run and the surface would become rough. It is better to let the paint dry - it only takes about an hour or two - and rework the entire surface."

Significant time savings thanks to the low-fog spray technology

After about four minutes, the door leaf is completely painted. Compared to hand painting with a brush and roller, which takes around 20 minutes for an experienced processor, significantly faster. Of course, it is not the pure application time that is decisive, but the entire working time including set-up times. The process of setting up the construction site is limited. The size and weight of the motor blower are reminiscent of a household vacuum cleaner. So it can be easily transported by one person. Commissioning is straightforward: connect the motor fan to the power supply, plug in the air hose and connect it to the gun at the other end. You can start spraying - provided paint has already been filled into the suction container. Since the varnish is ready for processing, it is sufficient to simply stir it up. If you also want to save yourself having to refill, you can use a can adapter that can be used directly from the paint can (750 or 1000 milliliters).

And what about cleaning after work? Here the water-based paints used again show their advantages. The paint cup and all of the individual parts of the gun, which can be easily disassembled, can be cleaned under running water. A small brush, which is included in the scope of delivery, ensures that no paint residue remains. After about five minutes, the gun is clean and can be reassembled. The brush and roller are also not cleaned much faster. “The pistol doesn't have to be washed out during breaks. It is sufficient to close the openings of the spray nozzle with a piece of adhesive tape. So you can continue working immediately after a break in work,”Yannick Heil also advises.

The bottom line is a significant time saving. In the case of the filling door, this is around 30 minutes, since the door usually has to be coated twice when hand-painted. The time saved would be even greater with slat shutters.

Competition for the airless device?

The advantages of the low-fog spray technology are obvious and should immediately convince any painter who delivers good quality and still wants to make money. This is definitely the conclusion I reached in my test. The acquisition costs are also unlikely to deter. With around 850 euros for the basic device plus a special NAST front-end nozzle, this results in a very good price-performance ratio. Yannick Heil suspects that the device could rather be seen as "competition" to the airless device, which is already available in most painting companies. But Caparol strongly rejects this. The low-fog NAST spraying process with the specially developed paints is recommended for coating small to medium-sized areas. So for surfaces,for which the painter would not use an airless sprayer because its use would be uneconomical due to the cleaning effort. For NAST applications, for example, painting garage doors, radiators or door frames is ideal. But the use of low-fog spray technology also makes sense on small-area components such as banisters, because using an airless device would cause too much spray mist. As a rule of thumb it can be said: NAST up to 50 square meters and wherever only a small spray mist load is acceptable; Airless devices are still the better choice on larger areas from around 50 square meters - at least from an economic point of view.painting garage doors, radiators or door frames. But the use of low-fog spray technology also makes sense on small-area components such as banisters, because using an airless device would cause too much spray mist. As a rule of thumb it can be said: NAST up to 50 square meters and wherever only a small spray mist load is acceptable; Airless devices are still the better choice on larger areas from around 50 square meters - at least from an economic point of view.painting garage doors, radiators or door frames. But the use of low-fog spray technology also makes sense on small-area components such as banisters, because using an airless device would cause too much spray mist. As a rule of thumb it can be said: NAST up to 50 square meters and wherever only a small spray mist load is acceptable; Airless devices are still the better choice on larger areas from around 50 square meters - at least from an economic point of view. NAST up to 50 square meters and wherever only minimal spray mist is acceptable; Airless devices are still the better choice on larger areas from around 50 square meters - at least from an economic point of view. NAST up to 50 square meters and wherever only minimal spray mist is acceptable; Airless devices are still the better choice on larger areas from around 50 square meters - at least from an economic point of view.

Because for the craftsman, less spray mist also means a much more pleasant work situation. This is particularly noticeable when working overhead. B. when coating wooden ceilings. Even in confined spaces and in poorly ventilated rooms, the handy low-fog spray technology often proves to be more advantageous.

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