Spots on aluminum after PAA
Spots on aluminum after PAA
(OP)
Howdy all,
I'm Phosphoric Acid Anodizing full sheets of 2024-T3 Bare aluminum and some sheets come out with spots on them. I have included a couple of pictures. The spots are about 1/4 inch across. I'm a bit stumped as to the cause. I took a 3M abrasive pad and rubbed a few of the spots and reran the sheet but they were still visible, but I didn't want to get too aggressive with them. We are following a process similar to BAC5555, with a solvent wipe, aqueous degreasing, sulfuric acid/sodium dichromate etch, PAA and rinses with water break free check between each. Any suggestions?
http://files.engineering.com/getfile.aspx?folder=d...
http://files.engineering.com/getfile.aspx?folder=3...
Thanks,
-Kirby
I'm Phosphoric Acid Anodizing full sheets of 2024-T3 Bare aluminum and some sheets come out with spots on them. I have included a couple of pictures. The spots are about 1/4 inch across. I'm a bit stumped as to the cause. I took a 3M abrasive pad and rubbed a few of the spots and reran the sheet but they were still visible, but I didn't want to get too aggressive with them. We are following a process similar to BAC5555, with a solvent wipe, aqueous degreasing, sulfuric acid/sodium dichromate etch, PAA and rinses with water break free check between each. Any suggestions?
http://files.engineering.com/getfile.aspx?folder=d...
http://files.engineering.com/getfile.aspx?folder=3...
Thanks,
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.





RE: Spots on aluminum after PAA
Suggest submitting process info, photos and questions to...
http://www.anodizing.org
http://www.metalfinishing.com
http://www.finishing.com
May be something as simple as surface prep or bath agitation.
Regards, Wil Taylor
Trust - But Verify!
We believe to be true what we prefer to be true.
For those who believe, no proof is required; for those who cannot believe, no proof is possible.
Unfortunately, in science what You 'believe' is irrelevant – "Orion"
RE: Spots on aluminum after PAA
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.