No passwords, No popups, No AI, No cost:
we earn from affiliate purchases

Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Adver-
tise
Help
Wanted
Current
Q&A's
Site 🔍
Search
ted_yosem
Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
finishing.com -- The Home Page of the Finishing Industry

  The authoritative public forum
  for Metal Finishing since 1989
  mfhotline


  -----

Contaminant Build up in Anodize Line Rinse Tanks

none
finishing.com is made possible by ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages


RECOMMENDED ANODIZING & CHROMATING BOOKS
for Shops, Specifiers & Engineers


probertEthumb
"Aluminum How-To" -- Chromating, Anodizing, Hardcoating by Robert Probert (2005)
avail from finishing.com

pinner
"The Surface Treatment & Finishing of Aluminium and Its Alloys" by Wernick, Pinner & Sheasby (1959 - 2001)
avail from eBay, AbeBooks, or Amazon

anodizing_runge2018
"The Metallurgy of Anodizing Aluminum" by Jude Mary Runge (2018)
avail from eBay, AbeBooks, or Amazon

surface_aluminum_king
"Surface Treatment and Finishing of Aluminum" by Robert King (1988)
avail from eBay, AbeBooks, or Amazon

anodic_ox_alum_henley1982
"Anodic Oxidation of Aluminum and Its Alloys" by V. F. Henley (1982)
avail from eBay, AbeBooks, or Amazon

alum_finish_reynolds
"Aluminum Finishes Process Manual" by Reynolds Aluminum (1973)
avail from eBay, AbeBooks or Amazon

(as an Amazon Associate & eBay Partner, we earn from qualifying purchases)

Q. Hey there! I have a small anodizing shop where we have decided to modify our line with a cascade counterflow rinse arrangement. We are seeing an interesting build up of contaminants, but I'm unsure if this is affecting our quality further down.

Our tank arrangement leading up to anodize is:
Soap
Soap Rinse
Etch Rinse
Etch
Deox Rinse
Deox
2nd Rinse
Anodize Rinse
Anodize

Our cascades are:
Fresh --> Sulfuric Rinse --> Deox Rinse --> Etch Rinse --> Drain
Fresh --> 2nd Rinse --> Soap Rinse --> Drain

Our line procedure leading up to anodizing is:
--> Soap --> Soap Rinse --> Etch Rinse
--> Etch --> Etch Rinse --> Deox Rinse
--> Deox --> Deox Rinse --> 2nd Rinse --> Anodize Rinse
--> Anodize --> Anodize Rinse --> sealing

With the cascade, we are overall seeing a marked improvement in the quality of our Rinses. However, our Etch Rinse quickly turned a deep tomato orange and developed white "floaties" that easily clump and break apart. They seem to easily rinse off with a sprayer, and they don't seem to be transferring to our Deox Rinse. We knew that the Etch Rinse would look "dirtier" and "cloudy" but this seems extreme. Pictures attached.

61623-1a   61623-1b  

My questions are:
1) I'm assuming the floaties are sodium sulphate, resulting from the weak sulfuric from the anodize rinse and the deox rinse neutralizing the sodium hydroxide getting dragged in from the Etch. Would this be accurate?
2) How much should I worry about the floaties (if they are sodium sulphate) affecting the cleanliness of the aluminum? Is it likely any of it might "stick" to part surfaces that could affect the anodize?

Thank you!

Jeremy Tollefson
- Sacramento CA
December 13, 2023




(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

Finishing
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g,
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"