Preventing lacquer overspray

Tops on preventing overspray when applying lacquer topcoats. August 23, 2000

I often have a problem with overspray settling on areas already lacquered when spraying with precatalyzed nitrocellulose lacquers (i.e., inside of drawer boxes, inside corners of cabinets and even adjacent outside corners).

Even when I flood the areas thick, I am still getting overspray somewhere. Is my solution to invest in an HVLP system?

Forum Responses
Overspray? Is your gun set up so that you are spraying at the lowest possible pressure?

Can you add some retarder to your finish so that it stays wet longer (that way it may accept the overspray as part of the finish and maybe the overspray will "melt in" better)?

On the other hand, adding retarder means that your overspray will indeed be wet overspray, and everywhere it lands will be "stuck" with it. I think we all hope that the overspray we get is already dry before it reaches anything, and that as dust, all it does is settle without creating a finishing nuisance.

If you need a gun with less overspray, then HVLP is one way to go. But there are two types of HVLP: conversion guns, which run off of compressed air, and turbine outfits.

Another option -- and an industry favorite -- is the Kremlin Airmix air-assisted airless sprayer. Overspray with this gun is virtually non-existent. Imagine being able to spray the inside of a cabinet with no fog bouncing back into your face! Even if you used an aerosol can, you would get a fog, but not with this universally acclaimed spray setup.

A less expensive alternative to the AirMix (and not quite the same performance in either spray quality or reduction of overspray) is an Italian import brand of conversion guns called Asturo.

We just went to a Kremlin AirMix and spraying the inside of cabinets and drawers is 300 percent better.

I would first look at your spraying style. Have a rep take a look at your gun to see if it is set up correctly. I can make any gun spray lousy if I want to sell the guy something else, even the Kremlin! I also want to add that, as all these coatings companies revise their formulas for VOC reasons, it seems everybody with an HVLP runs for the retarder! Meanwhile, everybody wants everything to dry faster for production reasons, right?

Well, if you add high volumes of atomizing air to a quick-drying coating the result is more overspray. Also, this high volume creates a wind vortex in the corners, hence it is hard to finish those inner box corners. That's why air-assisted airless works so well; you get the benefits of airless but at a lower fluid pressure, thus less bounceback; and the small amount of atomizing air helps diffuse the "tails" on the spray pattern, and also makes the fan controllable.

Bob Niemeyer, forum moderator