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WHITE SPOTS ON T4 ANODISING

WE HAVE BEEN ANODISING EXTRUDED T4 6261 HARD ALLY FOR AROUND A YEAR NOW. RECENTLY WE HAVE BEEN HAVING SOME PROBLEMS WITH THEM THOUGH. THESE ARE FRAMES FOR A CHAIR, AS SHOWN, IF THAT HELPS AT ALL. WE HAVE BEEN GETTING WHITE SPOTS AROUND DRAIN HOLES, AND A VERY STICKY SOLUTION AS WELL. HERE ARE THE FACTS ON THE MATERIAL USED.

T4 6261 HARD ALLOY, HEAT TREATED POST BENDING TO T6. 32 GRADE HYDRAULIC MINERAL OIL IS USED FOR BENDING AND WIPED CLEAN WITH turpentine ⇦this on eBay or Amazon [affil links] .

THESE ARE FIRST DEGREASED IN P3 ALMECO, ETCHED IN A P3 ETCH, DEOXIDIZED IN P3 ALMECO 90, ANODISED IN sulfurIC AND OXALIC ACID, AND SEALED IN ANOSEAL 30C. ALL CHEMICALS SUPPLIED BY HENKEL.

ANY COMMENTS OR QUESTIONS ARE MORE THAN WELCOMED.

ANDREW FALCONER
- CHRISTCHURCH, NEW ZEALAND
2002

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For the benefit of my clients I have just made a two page list of causes of "White Spots", and uploaded it into the Library section of finishing.com's web site. You mentioned the oxalate additive, well, Calcium Oxalate is a white powder. Get back to me, or any one else out there, with any other questions on "White Spots".

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2002