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What You Need to Know About Coating Galvanized Steel

in Application Techniques

Galvanized steel is a type of steel that has been galvanized by the application of a zinc coating to protect it from corroding or rusting.

“That means you’re not painting steel, you’re painting zinc,” says Gary Vorick, Global Training Manager, Sherwin-Williams.

Here’s what you need to know to prevent paint failure on this problematic substrate.

Ensuring adhesion

One of the biggest challenges in painting galvanized metal is achieving proper adhesion, and most problems start with either pre-treatments, poor surface preparation or improper choice of coating system. If not prepared and painted properly, galvanized steel will tend to peel over time.

Proper surface prep

Proper surface preparation may start with solvent cleaning to remove oil/grease contamination. But if the galvanized surface is shiny, the surface must then be de-glossed and roughened. Vorick recommends following the Society for Protective Coatings (SSPC) SP-16 standard when prepping galvanized steel.

Factor in substrate consistency

Also, since different galvanizing shops may employ different surface treatments or processes, what worked well with one project may not necessarily work for another, making it challenging to obtain consistent results from one project to another.

Best coating choices

For most galvanized steel coating jobs, Vorick recommends using Pro Industrial™, a line of high-performance coatings formulated by Sherwin-Williams to withstand the harsh conditions of busy commercial and institutional environments.

Talk with your sales rep to get help on choosing the right product for your situation. Or watch the video below to learn about the specific properties of the different Pro Industrial coatings.


This article was originally published in the Spring 2017 issue of the Sherwin-Williams CommercialPro newsletter. Get more business-building tips and info on products, services, discounts and project solutions on the Sherwin-Williams contractor website

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