Troubleshooting Mottling with Spray Stains

Advice on better equipment and technique to achieve an even spray pattern. March 28, 2012

Question
I've recently started to spray stains/dyes and can't seem to get rid of the mottling. Would a better gun help eliminate this problem or is it more likely user error? The gun that was recommended was a Devilbiss trans tech gravity.

Forum Responses
(Finishing Forum)
From contributor R:
Tape up some white paper on your shop wall. Keep adjusting your fluid control and fan knobs until you get a nice atomized pattern without a heavy or darker color in the center of your pattern. You get mottling from a center wet pattern. Overlap your pattern by 50 percent and you should be good to go. Keep your passes the same speed as you spray as well.

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From contributor J:
Some of the mottling is due to the way HVLP atomizes. A better gun such as the Devilbiss or CAT will help with this. Switching to a compliant air cap instead of an HVLP helps to improve this. Devilbiss Trans Tech is great. Also, it helps if you try to build the color in several passes instead of one pass.