Heads or Tails?

Q. My company recently bought an airless spray unit from a local equipment dealer to take advantage of its cost-saving increase in transfer efficiency. We’re experiencing a condition that’s described to me by my painter as “tails” in the spray pattern using our new painting equipment. The dealer’s representative told us that the problem doesn’t exist and even if it did he wouldn’t know what to do to eliminate it. Without luck, I eagerly read all the articles on airless spray painting hoping to learn how to eliminate these tails. Is there somewhere I can go to find out what steps to take? B. J.

 

A. Any dealer rep with a head on his shoulders would refer a problem such as tails in a spray pattern to the spray equipment manufacturer. You may want to call the manufacturer yourself to get a definitive answer. He will help you solve the problem because his continuing business depends on satisfied customers. Perhaps the rep was telling the truth when he said that he didn’t recognize the problem and doesn’t know what to do.

Tails in airless spraying is a well-known problem. The condition is caused by incomplete atomization of the liquid throughout the spray pattern resulting in a solid stream when paint that is too high in viscosity is sprayed. This generally occurs at the ends of the pattern. Tails can often be eliminated by reducing the paint’s viscosity by thinning with solvent.

However, this solution may cause you to be in non-compliance with air quality standards. It may also be possible to eliminate tails by raising fluid pressure or by heating the paint using an in-line heater. Changing spray nozzles may also eliminate the problem.