In the 12th video of our question and answer video series “Airless Q&A” we are dealing with a request on the topic of lime paint. Lime- and chalk paints have always been used as a coating. Many of our agricultural customers use lime coatings to whitewash their barns. In recent years, however, limescale has developed into an ecological trend and more and more people want lime coatings for their own health and environmental reasons. However, lime paint usually must be applied several times (depending on the material 3-4 times or even more frequently), thereby increasing the labor and time required as well as the costs incurred. The use of an Airless device offers the possibility to apply lime paint in a high-quality and time-saving manner. However, there are a few factors to consider. In the video, we have summarized the most important questions about spraying lime paint with airless paint spraying equipment.
The right nozzle for Airless spraying of lime paints
In our training and testing center for spray technology we tested various lime paints. It has been shown that relatively large nozzles must be used, otherwise it quickly leads to clogging of the nozzle. If the nozzle is too small, the solids accumulate and clog the nozzle directly. With the spray tip clogged, applying the material becomes impossible. Therefore, the nozzle must be large enough. The test showed that, depending on the paint manufacturer, 525 (0.025″ bore hole size) to 531 (0.031″ bore hoel size) nozzles were suitable. These are relatively large nozzle bores, but only with these larger spray tips can the solid components of the lime paint pass through properly and the clogging of the nozzle be prevented. A prerequisite, however, is that the sprayer has a sufficient delivery rate, otherwise these large nozzles will not be sufficiently supplied with paint.
Matching main filter & gun filter for lime paint
So that the lime paint does not clog the sprayer and the main filter directly, it is necessary to choose a coarse-meshed main filter. After several experiments, it was shown that coarse-mesh filters with a mesh size of #30 were best suited as the main filter.
You do not use a spray gun filter. We found that #60 spray gun filters clogged very quickly, so we did not use spray gun filters and sprayed lime paint without a filter in the spray gun handle.
Which sprayers are suitable for spraying lime paint?
Lime paint appears very watery and thin, so that the impression can arise that the material would be very easy to spray and even with less powerful airless devices. However, this assumption is precluded by the high proportion of solids in the paint. The solids require the use of larger nozzles (eg, 525 or 531) because smaller nozzles clog immediately. High-performance airless equipment is required to use these large nozzles, otherwise the performance is insufficient to sufficiently atomize the paint and produce a usable spray pattern. Therefore, sprayers with a capacity of three liters per minute or more should be used. DIY, home improvement and entry-level models are completely unsuitable for this purpose. Also, the screening of the color does not help here, since the sieving of the solid components changes the properties of the color.
Here are some examples of suitable Airless sprayers for the application of lime paints:
FARBMAX Airless M10 for spraying lime
The FARBMAX Airless M10 is a simple, robustly constructed diaphragm pump with which lime paint, primer, dispersion, fabric adhesive, facade paint and even roof coating can be applied. The sprayer has enough power to handle larger lime paint nozzles.
Graco Ultra Max II 795 for lime paint
In our lime paint spray test, we used the Graco Ultra Max II 795 Standard at our Airless Discounter Academy. It is an electric piston pump with 3.6 l / min delivery rate, sufficient to supply larger nozzles for lime with paint.
Wagner PS 3.31 Piston pump for lime
The Wagner PS 3.31 is also an electric piston pump with a delivery rate of 3.8 l / min, ie sufficient power for lime paints.
If you haven’t already, be sure to watch our video and let us know your thoughts. Have you sprayed with lime paint? How have you found the application process to be?
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Questions or queries?
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