I'm using spray gun with automatic reciprocator system to coloring stainless steel sheet with some translucent lacquer. However, I found the color is unevenly sprayed and can't figure why is it uneven.

I've tried several ways including:
1.Different distance between spray gun and the steel sheet.
2.Different angle of the spray gun.
3.Moving speed of the spray gun.
4.Spray times and spray volume.
5.Air pressure of the spray gun.
6.Pressure of the lacquer.
7.Different temp and humidity.(64F~85F, 3X%~7X%)
8.Different spray gun.(Iwata LPA-200 and other locally manufactured spray gun.)
9.Cleaning the gun.

It looks like blushing but I think it's not blushing because the following reason:
1. Situation gets better when I tune the air pressure higher while it is believed to be worse if it's blushing.
2.I also tried different temp and humidity.(64F~85F, 3X%~7X%)
3.I've tried to heat up the steel sheet to about 85F-90F before spray but still in vain.
enter image description here enter image description here enter image description here enter image description here Is there anybody know the reason?

  • Another factor : skill of the operator... Probably the most critical. – Solar Mike Aug 27 '18 at 6:05
  • @SolarMike Thank you for reply, could you give me more suggestion about this situation? – nosnhoj Aug 27 '18 at 9:08
  • May be an overly simple point, but are you sure the lacquer and pigment are well mixed? – kyle_engineer Aug 27 '18 at 19:42
  • @kyle_engineer Thank you, I've wondered if it's not well mixed before and tried stir the lacquer while I'm spraying but still in vain. – nosnhoj Aug 28 '18 at 0:51

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