Ask the Expert Question-and-Answer Archive

by Ron Joseph

June, 2005

Application of Etch Primer Over Alodine Conversion Coating

Q. I am using the Dupont Imron paint system to paint my T6061 aluminum kitplane. The three step system applies:

1. Etching Primer
2. Secondary Primer
3. Finish Paint.

Before application of the etching primer, should I wash all parts with Alodine, or simply scrub wash it?

A. It is never advisable to apply an etch primer over Alodine conversion coating for aluminum. If you have the ability to apply the Alodine following the vendor's recommended process, then that will give you better adhesion than if you use the etch primer. Application of the etch primer is only intended for people who, for one reason or another, cannot apply the conversion coating.

It is always necessary to remove all grease, oil and other contaminants from the aluminum surface, but you must insure that if you use a soap (detergent) solution you must thoroughly rinse off the soap and allow the aluminum to dry before applying the etch primer.

Best wishes,

Ron Joseph