Metal finishing Q&As since 1989

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RE HARDCOATING A PART WITHOUT STRIPPING

I have a 6061-T6 Alum part that was hard anodized MIL-A-8625 / MIL-PRF-8625 [on DLA], TYPE III Class 2 Black using Hot aqueous Solution of Nickel Acetate.

I then reamed one of the tight holes. I took off material, but to my amazement all the black was gone. Is there anyway to Hardcoat the part again to get it in the hole or will that destroy it?

I need the hardcoat to protect the hole's ID.

My friend says to just re hardcoat it and the existing hardcoat will "mask" the part while letting the re machined areas get the coating they need.

My other friend said, throw out the parts and start fresh.

Sean Donovan

2006

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You have some funny friends.
If contact can be made-check with your local anodizer, then it is possible, as your first friend stated. Again, it depends if good contact is available.

Bill Grayson
metal finishing - San Jose, California
2006

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Preprocess tanks will work a hardship on the hardcoat, but not that bad and you will add some more so you should be OK if you can make very good contact.
Next time, lap the holes and do not ream, even a tiny bit.

James Watts
Navarre, Florida
2006