Black Coating for Aluminum

Question:

I am doing some research on the full range of potential coatings and associated application methods to apply a uniform black coating to the surface of an aluminum automotive condenser product. "Normal" spray techniques, for both liquid and powder, and the associated ovens and material handling equipment, are very expensive and labor intensive.

The product will be somewhat amenable to IR heat processing or IR/convection combination. The coating will need to withstand fluids, such as windshield washer fluid, without degradation along with some heat tolerance, similar to that under the hood of a car.

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I was wondering if you could shed some light on the subject from your experience with any coating(s) and/or inks that might be a good fit for the product and also further my knowledge of what is available in industry to get a uniform black appearance on a product in a simple, inexpensive way? Thank you for your consideration. D.W.

Answer:

I was going to title this question "Something to Dip Into" after a series by that name that ran in past issues of Painting Clinic. Maybe that's what you really want. On the other hand, there are other processes available that could suit your needs, such as electroplating, anodizing, etc., that I don't cover in this column.

I will suggest the painting processes, such as powder coating, liquid high-solids and waterborne coatings, electrocoating and autophoretic coating. These products are applied by dipping and spraying and most require ovens to cure the applied coatings. However, there are liquid coatings that can be force dried using IR radiation. Suppliers of these materials can be found at www.pfonline.com on the "Suppliers" page or in the 2001 Products Finishing Directory and Technology Guide. These materials can be applied by spraying or they can be "Something to Dip Into."