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Painting Aluminum Sheet Metal

 

I would like to know the best way to pretreat aluminum sheet metal for painting. This sheet metal will be used inside a lighting research chamber and may be exposed to heat (not more than 200 F). We don't want the paint to bake off and cause more work. It is important that the paint has a very flat white appearance. So what should we do? Sandblast the surface? Use a primer/cleaning process? Any information will be helpful.

Thanks,

Ben O'Brien
- Omaha, Nebraska, USA

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Aluminum needs a pretreatment on it because paint will not stick. You could use a Self-etching primer ⇦this on eBay or Amazon [affil links] and white topcoat. Or you could send it to a processing house and have a Chemical Conversion coating applied. For your application a Class 1A film would work.

Steve Adams
- Cedar City, UT, USA

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2007

Painting on Aluminum Sheets of 0.7 mm for Air Conditioning Ducts. We need to Paint Aluminum Sheets used for Al Cladding applied on GI Duct work.
The Paint finished required is RAL 1015. Please suggest a suitable method.

Regards

Rahul Duragkar
Engineer - Dubai, UAE

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RAL 1015 says nothing except that the color is a particular shade of "light ivory", Rahul. I suppose, lacking any other info, I would chromate conversion coat or TCP conversion coat the aluminum and then apply one coat of polyester powder coating? Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2007

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December 26, 2008

Our company is doing painting works to support the fabrication of ATM for our customer. We are using different color painting and powder coat. If there is any new paint, I will do the evaluation on the basis of supplier spec to know the paint is ok to proceed in production. Usually, I will do the mechanical tests like Impact, Cross hatch, pencil test etc. Currently, I am struggling with the one powder which always failed of impact test. The substrate I used is CRS. Prior to the powder coat, the part is coated with another layer of ED coat. The baking temp will be 180 °C for 15 minutes for the powder coated part. What should be the failure reason for this coating?

Anil
Process Engineer

Anil Kumar
- Singapore