Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site

pub
Free personalized metal finishing help!


Precleaning of Aluminum before Alodine treatment



(-----) 2004

Q. I work at a composite aerospace structure manufacturer. I was hired on to run the NDI Department but since Chemical Processing is also a "Special Process" I was given major responsibilities in the Alodine area. We will be having a Nadcap audit this month and I have a problem. We produced metal aircraft components prior to doing the composites, primarily aluminum sheet metal parts for cabinets. In the past the parts were either sanded or scotchbrited for the precleaning. We perform a monthly salt spray test to verify the process and have never had a failure, to my knowledge. But the water break test was not performed. I have checked a sample of parts and they do not pass the water break test all the time. We currently have a 20% NaOH / 50% HNO3 Aluminum Etch line for Pre-penetrant etching, but Mil-C-5541 [link is to free spec at Defense Logistics Agency, dla.mil] recommends NOT etching the parts prior to Alodining. We are a small company and would like to stay away from heated tanks, if possible. What options do I have.

Buddy Jeter
Aerospace - Bridgeport, West Virginia, USA
^


2004

A. Switch to proprietary chemicals. There are good low etch alkaline cleaners available from some of the major vendors and they can also help with the tech support.

James Watts
- Navarre, Florida
^


2004

A. Sanding imbeds all kinds of junk into the soft aluminum and this requires a massive deep etch to remove such imbedded soil (iron, silicon,organics, etc.)

robert probert
Robert H Probert
Robert H Probert Technical Services
supporting advertiser
Garner, North Carolina
probertbanner
^



April 9, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Before we do Alodine for 2024-T3 aluminium sheet we are rubbing the sheet with use of scotch-brite. Is it correct? And we need to know correct procedure of Alodine for 2024-T3 alclad sheet.
Thanks,

Asoka Cooray
- Male, Maldives
^

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

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:

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


About/Contact    -    Privacy Policy    -    ©1995-2022 finishing.com, Pine Beach, New Jersey, USA