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Pretreatment for aluminum for powder coating using 3 stage spray wash.

My name is Andrew, the company I work for is interested in applying a powder coat finish to aluminum panels. We have a 3-stage spray wash system that we currently use to pretreat mild steel products for powder coating. I understand there are a number of multi-metal cleaning products that can be used on both steel and aluminum (5052). The question I have is: Is there a recognized paint standard for aluminum (like the AAMA series) that I can meet using a 3 stage system that does not include a conversion coat stage? Thanks.

Andrew Shepland
Sheet Metal Fabricator - Rochester, New York
October 9, 2008

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The accepted definitive spec for good pretreatment is the salt spray test, not how many stages you have. A multi-metal phosphate in a three stage washer with DI water rinse should give you excellent salt spray results on aluminum. Your chemical vender is the guy to go to with this inquiry. If there is a standard such as the one you are looking for, he has it and can help you meet your goals. If you aren't getting help from him it's time to find a new vender.

Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina
October 15, 2008