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Ted Mooney, P.E. RET
Pine Beach, NJ
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for Metal Finishing since 1989
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Runs streaks in type III black dye
Q. We recently developed an issue were we are getting "runs" under our black dye type iii. Was wondering if anyone could pinpoint the issue -- containments somewhere along the line, inadequate prep work or something completely different? This is 6061-T6 being bright dipped, then type III coated with black dye.
Chris Jonesproduct design & manufacture - Coopersburg, Pennsylvania
October 20, 2016
A. Chris
The blemish looks to be the result of inadequate rinsing after anodize and before dyeing. To confirm, observe the blemish before unracking. Residual acid from the anodize is heavier than the dye solution, and will run down from the origin.
If this is the case, options include better rinsing (longer, agitated, cleaner), a mild nitric acid dip, and an inspection 1 - 2 minutes after immersion into the dye solution; while the parts are not yet black, the blemish will usually be visible. If found, repeat the two previous options and dye again.
A poor man's fix would be to moderately agitate the parts for the first 1 - 2 minutes of the dye immersion to 'rinse' away the acid.
- Green Mountain Falls, Colorado
October 26, 2016
Thank you for all of your help! We will give this a go, makes total sense.
- Coopersburg, Pennsylvania, USA
October 26, 2016
Q. Chris, we're having a similar issue. Did the better anodize rinse help?
Thanks
- toano, Virginia, USA
July 27, 2017
A. Yes, better rinsing was our solution, Thanks.
Chris Jones [returning]- coopersburg, Pennsylvania
July 27, 2017
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