No registration, no passwords; no pop-up ads -- just aloha, fun, & authoritative answers.
As an eBay Partner & Amazon Affiliate we receive compensation for qualifying purchases.
Home /
Search 🔍
the Site
pub  Where the world gathers for
plating, anodizing, & finishing Q&As since 1989


Non-etch stripping of anodic coatings on aluminum

Q. I'm interested to see what the industry is using for the removal/stripping of anodic coatings. We are currently using a caustic etch solution and are looking for a NON-ETCH strip solution. If you have any experience with a particular product your comments and recommendations would be appreciated

Tim Martin
plating shop - Springfield, Massachusetts


A. If stripping anodize coatings from aluminum the following solution can be used:

Bring to boil and strip for 3 - 5 minutes. This solution will strip the anodize coating but will not etch the aluminum substrate.

Greg Haataja
helicopters - Fort Worth, Texas

Q. I have a client using a solution of ~ 3.5% Phosphoric acid and ~ 2.0 Chromic acid to strip anodized materials. It works fine...

The problem is the rock-like solids that build up on the walls of the strip tank. Short of using a jack- hammer he is unable to remove the material. Do you have any suggestions for cleaning out this strip tank?

Art Kushner
Art Kushner
Anaheim, California

A. Hi, Art.

The precipitant salts of aluminum (and some other metals) have a way of settling and pushing out the liquids they were not quite floating in. I discovered a few times that if you have one on these aluminum solids settled in a bottle, hard as a rock, with the liquids floating above it, that inverting the bottle a hundred times or so will get all that aluminum back in suspension. From this I am pretty confident that you can "wash" this precipitate back into solution by, for example, filling the tank with water, and pumping that water through a hose sprayed at the solids, and recirculating. Then you have to pump out the liquid and the resuspended solids before they settle and harden again. Good luck.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

(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:

Chemicals &
Consult'g, Train'g
& Software

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