2024-T3 bare Anodize vs. Alodine
2024-T3 bare Anodize vs. Alodine
(OP)
I have a part (a spar/avaition part) that was suppose to be made from 2024-T3 alclad, instead it was made from 2024-T3 bare.
The finish spec call outs that the part can be anodic coated per Mil-a-8625 or Alodined per Mil-c-5541 (then one coat of primer). Pervouis batches (proper material) of parts have been alodined.
We want to keep the parts (cost and lead times on them are high) and the best choice would be to Chromic anodize/seal them.
I need some kind of justification/base though. So my question is if anybody knows of a document that compares the corrosion resistance of 2024 bare vs 2024 alclad for anodizing vs alodine?
The finish spec call outs that the part can be anodic coated per Mil-a-8625 or Alodined per Mil-c-5541 (then one coat of primer). Pervouis batches (proper material) of parts have been alodined.
We want to keep the parts (cost and lead times on them are high) and the best choice would be to Chromic anodize/seal them.
I need some kind of justification/base though. So my question is if anybody knows of a document that compares the corrosion resistance of 2024 bare vs 2024 alclad for anodizing vs alodine?





RE: 2024-T3 bare Anodize vs. Alodine
I remember a similar question - though not sure of the Grade - coming up at a previous employer in the UK.
I can't remember the details but there was an RAE (or one of those govt agencies) report about the impact of Alclad V certain other 'treatments'.
I think we came to the conclusion that for our application the alclad was beneficial/needed.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: 2024-T3 bare Anodize vs. Alodine
http://www.finishing.com/199/16.shtml
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: 2024-T3 bare Anodize vs. Alodine
But thats the first thing i found when doing a google search too. Not really much help though in this situation.
I'm looking for some kind of qualitative comparison (some kind of doc or spec) so I can justify accepting the part and insuring that the corrosion resistance is acceptable or comparable to 2024 alclad thats been alodined.
I.e. a salt spray comparison of different alloys with different coatings.
RE: 2024-T3 bare Anodize vs. Alodine
Or did you mean you want a Free doc or spec?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: 2024-T3 bare Anodize vs. Alodine
Have you been through the book? I don't want to have to raise a purchase order to buy a book that may or may not be useful. (Usually google books will give you a preview to see if it contains useful information. not for this book though)
Does that book do a comparison or does it just go through each process and not really compare them?
RE: 2024-T3 bare Anodize vs. Alodine
RE: 2024-T3 bare Anodize vs. Alodine
israelkk. Its one of those supplier screw up kind of deals where the parts went though the whole forming process before it was caught. Where the end solution would be to scrap the parts, but I'm hoping of finding a bases to save the parts due to lead times. (next batch will be from proper material). Mil-s-8625 is the bases for anodizing (2024 is still under 5% Cu cut off for chomic) Sulphuric would be better though. The only problem is I still need a documented bases to compare too? parts an external part aswell.
RE: 2024-T3 bare Anodize vs. Alodine
RE: 2024-T3 bare Anodize vs. Alodine
The maximum content of alloying elements of 2024 is beyond the 7.5 percent (as far as I recall it close to 9%). Therefore, for maximum protection you need to use Type II (sulphuric). I also have actual experience of aerospace part of 2024-T3 that was coated by chromic anodize and failed the salt spray test. After removal and re-coated by sulfuric anodize it passed the 336 hours.
RE: 2024-T3 bare Anodize vs. Alodine
I will dig deeper into in and will likely go with sulfuric then. I have been tied up lately and haven't had time to actually get into the research in order to produce the report.
With all your experience, you wouldn't know of a documentation that 2024 Bare anodized (sulfuric) would meet the corrosion resistance of 2024 alclad alodined? I knew this was going to be a pain when I got this file, most the information I have got (from other sources) is experience and word of mouth, which is not hard data to base it on.
RE: 2024-T3 bare Anodize vs. Alodine
What is the price of the book at that link compared to scrapping the parts? (not just direct cost but cost implications of delaying delivery etc.)
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: 2024-T3 bare Anodize vs. Alodine
William Gunnar
http://www.IndustrialCoatingsWorld.com