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black chrome problems

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  • black chrome problems

    I have a sportster air cleaner cover I am coating in black chrome with a super chrome undercoat. I spray out the undercoat and it looks great. then i spray out the black chrome and the color is great but there are spots in the black chrome. They look like the powder just pulled away from the areas. I coated the parts twice with the same results. I have cleaned the part with purple power and water and then cleaned with acetone. The spray scheduel went chrome base sprayed, part at room temp, cooked at 400 for 7 min, air cooled to 154, sprayed black chrome, goes on fine all coated, cooked at 410 for 15 minutes. pulled out and there are the spots. pics attached.....
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  • #2
    Re: black chrome problems

    what gun are you ussing
    is this happening with this color only ?

    same thing happend to me when i first got my nordson
    I had a bad resistor and a bad ground point on my booth.


    • #3
      Re: black chrome problems

      Looks like fisheyes (contaminents such as oil), but it's hard to tell from the pics. If the chrome didn't do it then maybe something is getting onto the surface between coats. Moisture in your lines will cause this too, and candies will do it worse than solids. Try being extra careful keeping the surface clean and a moisture filter right at your gun. If you have one already change it and try that.
      Last edited by chromeitout; 11-30-2006, 10:15 PM.


      • #4
        Re: black chrome problems

        Have you tried spraying the black chrome separately?

        Like chromeitout said, from the pictures the defects do look like fisheyes. Another contamination source might be from traces of incompatible powder in your booth, or in the powder itself.

        Back ionization or poor grounding, like Jtagger19 mentioned, could also cause similar defects, but then your bottom layer would also show the spots.