No passwords, no registration, no paywalls, no popups, no AI

As an Amazon Associate & eBay Partner we earn from affil links

finishing.com -- The Home Page of the Finishing Industry

Search our quarter-million Q&As

Home of the finishing HOTLINE since 1989

-----

Does anodize improve coating adhesion?

Does anodize improve adhesion? There seemed to be a difference in the "feel" between the standard aluminum strip and the anodized strip. I had noted more drag or friction on the anodized strip.

The goal is to improve adhesion of a varnish to the strip.

Finally, what should the anodize look like under magnification?

1100-H18, .0045-inch thick aluminum coil

MIL-A-8625 / MIL-PRF-8625 [⇦ this spec on DLA], Type II, Class 1 (thickness per Table V (.000029 to .000093)

Thanks in advance,

Larry Boever
Mechanical Products - Brookings, SD
2006

"Adhesive Bonding of Aluminum Alloys"
by Edward Thrall
adhesive_bonding_aluminum

on Amazon or eBay
or AbeBooks
(affil link)

2006

"MIL-A-8625, Type II, Class 1 (thickness per Table V (.000029 to .000093)"

Hello, the above statement is a mis-quote from the spec. Actually table V states minimum thickness for type II coatings on 1100 seies aluminum as .000093".

The .000029" is for type I coatings.

Now to answer your question with a question. If adhesion is the issue, why not simply chromate?

Bill Grayson
metal finishing - San Jose, California, USA

Anodizing, preferably not sealed, will improve adhesion as compared to bare aluminum. Chromate film on aluminum is both less expensive and better for paint adhesion if the yellow color is not a problem.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
2006

In addition to Bill's and Jeffrey's helpful responses, please note that there is a phosphoric acid anodizing process (PAA) specifically for the purpose of adhesive bonding. One way of doing that would be under license from Boeing Commercial Products; I believe the process is called BAC5555.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
2006

Sorry! Finishing.com is temporarily Read-Only.
Ted Mooney is retiring but I have several offers to take it over.
We're working hard to make sure we find it the best new home.

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: