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Spraying High-Viscosity Paints

We have problems getting a consistently even distribution of a high-viscosity paint in the spray pattern, resulting in striping on the sprayed parts. To get better results, we are currently adding reducing solvents to lower the paint’s viscosity for spraying, and we have tried airless spray equipment from several suppliers with mixed results.

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Q. I manage the finishing facility at my plant where we are spraying a high-viscosity paint and have problems with the spray pattern. Our primary problem is getting a consistently even distribution of paint in the spray pattern. This has resulted in striping on the sprayed parts. To get better results, we are currently adding reducing solvents to lower the paint’s viscosity for spraying. We have tried airless spray equipment from several suppliers with mixed results. No matter what equipment we try, we still have a problem getting a repeatable, consistently even spray pattern. Can you recommend a company whose equipment will improve our application and hopefully eliminate the problem entirely? M.H.

A. In these times of high-priced solvents, their addition to paint for viscosity reduction is not cost-effective. Furthermore, it is counter-productive to the goals of the U.S. EPA and other regulating agencies whose goals are reduction of solvent emissions.

I cannot recommend specific suppliers, (visit PFonline.com for a complete supplier list), however you will get good results spraying high-viscosity, high-solids and even some 100-percent-solids paints using air-assisted airless spray equipment. This equipment should suit your needs since you will be able to control spray patterns in much the same way as with conventional air spray guns. Another approach to spraying high-viscosity paint is the use of high-rotational-speed bells and discs. 

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