-- The Home Page of the Finishing Industry
A website for Serious Education, promoting Aloha,
& the most FUN smiley you can have in metal finishing

topic 9929

Alodine required after powder coating?


I have multiple aluminum parts where the final product will have some surfaces powder coated while the remaining areas are just coated with an Alodine/Chromate conversion process. We apply the Alodine/chromate to the parts prior to powder coating to ensure good powder adhesion. However, because of the high temperatures the parts see during the powder coat process, our chemists have told us we have compromised the corrosion resistant properties of the Alodine/chromated surfaces and we need to reapply the Alodine/chromate to those otherwise bare surfaces (2 powder coats being applied (a color + a clear top coat) at ~ 375 deg x ~ 20 minutes).

We are not experiencing any problems with the reapplication or with our final products but would like to know if this reapplication is necessary, how this is generally handled in the powder coat industry, and if there are any other general concerns we should have with this process.


Beth Connors
Sandia National Laboratories - Albuquerque, New Mexico, USA


Yes, the powder coating bake has damaged the chromate and re-processing is the only way to get the chromate protection back to standard.

Don Brenner
- Lake Buena Vista, Florida, USA

This public forum has 60,000 threads. If you have a question in mind which seems off topic to this thread, you might prefer to Search the Site


Disclaimer: It's not possible to 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 may be deliberately harmful.

  If you need a product/service, please check these Directories:

JobshopsCapital Equip. & Install'nChemicals & Consumables Consult'g, Train'g, SoftwareEnvironmental ComplianceTesting Svcs. & Devices

©1995-2017     -    Privacy Policy
How Google uses data when you visit this site.