plating, anodizing, & finishing Q&As since 1989
Clear anodizing that looks like gray paint.
February 10, 2010
Since switching from a caustic etch to an acid etch we have had issues with some clear class I material having a dark gray tint to it. It's random, sometimes several pieces on a load, sometimes as few as one piece. We have checked extrusion, tempering parameters and everything is as it should be. We finish 6063 alloy extrusions. Could someone give advice on what to look for.James Justice
finisher - Midway, Tennessee
February 22, 2010
You should use caustic etching no acid etching.Carlos Carrera
- Miami, Florida
First of two simultaneous responses -- February 22, 2010
If staying with your acid etch, you may need change your de-smut chemical (HNO3) to a strong de-oxide chemical, and 4 min immersion at leastJohn Hu
Second of two simultaneous responses -- February 22, 2010
If it is random on one rack, and the air agitation is not hitting the work, then it is contact reliability.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina