Electrogalvanized vs. Galvalume

Question:

How do you rate the quality of the powder coating finish on electrogalvanized steel as compared to galvalume? Which one is easier to powder coat? W.P.

Answer:

Both of these materials are considered “paintable” grades of galvanized or zinc-coated steel. I would expect each material to powder coat equally as well as the other and without any remarkable difference. The key to obtaining the maximum performance from these high-quality and corrosion-resistant materials is proper pretreatment of the surface before powder coating. To take maximum advantage of the inherent corrosion resistance of these materials, I recommend the following pretreatment steps. First, clean the surface using an alkaline cleaning solution, then rinse with clean water. Second, etch or condition the surface using an acid based solution, followed by another rinse. Third, apply a zinc phosphate to the surface, again followed by a rinse. Last, apply a good sealer (chrome or non-chrome) to finish the surface pretreatment. This pretreatment, with a good powder coating, will achieve 1,000 hours, or more, of accelerated salt spray corrosion protection. Certainly, this is one of the best steel pretreatment and powder coating combinations used in everything from appliances to automotive parts.