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-----Affect of water on 6061 anodized aluminum
Aluminum How-To
"Chromating - Anodizing - Hardcoating"
by Robert Probert
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Q. I have a block that is type II anodized, class 2 with a blue dye. The block is prepped with a SS bead blast and degreased before anodize. The outcome is a rough textured surface.

In the field, water runs through the block around 20 bar and up to 100 °C. The blue dye (and maybe the anodize) is coming off the block. Other blocks that were not bead blasted, have a smooth surface, and a different color dye and are not affected. What is happening with the anodize on the blue blocks? Is there a way to stop it? Why does it not happen to the other colored blocks?
Bill Zebo- Minneapolis, Minnesota
September 19, 2024
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A. Hi Bill.
If any stainless steel beads remain imbedded into the surface then all bets are off regarding proper anodize prep, anodize, and dye & seal. But it should be relatively easy to test the thickness of the anodizing and to do a seal test.
Use a hall-effect thickness tester at several places to determine anodize thickness, and search the site with "anodize seal test" for the various seal tests.
Luck & Regards,

Ted Mooney, P.E. RET
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finishing.com - Pine Beach, New Jersey
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