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Anodizing as pretreatment for Aluminum (6061-T651)
We have a old part (last changed in 1969) that indicates the following finished procedure:
Step # 1 - Anodize per Mil-A-8625 [link is to free spec spec at Defense Logistics Agency, dla.mil] Type I Chromic Acid process, hot water sealed.
Step # 2 - Remove Anodize with alkaline etch "Hobart CE2" rinse in cold water. Desmut with "Hobart A45" deoxidizer (or equiv.)rinse in cold water.
Step # 3 - Anodize per MIL-A-8625 Type I Chromic Acid process, hot water sealed.
Would this still be valet finishing procedure to use?
God Bless AmericaWilliam E. Donohue
actuation systems - Whippany, New Jersey, USA
First of two simultaneous responses -- 2002
I can't say I am familiar with this multi-step procedure of chromic acid anodizing, then stripping, then chromic acid anodizing again. However, it doesn't sound intrinsically unsound. It is possible that it is specificed for dimension control: Anodizing adds a little thickness (a very little when we're talking chromic acid anodizing); maybe the anodizing and stripping is a way to reduce the dimensions such that when the final anodizing adds thickness, the dimensions are still okay.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Second of two simultaneous responses -- 2002
Yes, Yes, but the named proprietary alkaline etch and acid deox may not still be availbale, in which case you should contact any well known metal finsihing chemical vendor and proceed as before.
Robert H Probert Technical Services
Garner, North Carolina