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Can powder coat paints be used with galvannealed sheet metal?

I'm working on a outdoor product that is going to be exposed to UV rays from the sun. I need a colored surface and someone suggested a powder coat paint over sheet metal. I'm trying to keep costs down, so I'm leaning towards galvannealed. I was wondering if powder coat paint would readily adhere to a galvannealed surface or is there some unique surface preparation required?

Mark Boger
- Onalaska, WI
2001

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2001

Mark,

Powder coatings are frequently used to protect/color metal surface used outdoors. The suppliers of powder coatings have formulations which are colorfast/UV stable and will last years in out door exposure.

If a powder coating is used, generally, the surface preparation prior to painting is more critical than when using a liquid paint. Depending on the desired service life of our product and the type of service your product will see, it is likely that a chemical pretreatment will be needed to improve the adhesion of the powder coating to the metal surface (whether it is galvanneal, hot dip or another material). You should define the desired level of performance or service life you expect for you product and contact a powder coating supplier and a pretreatment supplier if you are going to perform these operation within you own plant.

If you are going to send your parts out for the application of the powder coating, many of the shops that perform this service can also apply a chemical pretreatment as well. Again, you should have some idea of the lever of performance you expect from the coating system and look for a combination of powder coating and pretreatment which will meet your requirements.

Roy Nuss
Trevose, Pennsylvania, USA