Hot-dip galvanized steel is often selected for its corrosion protection. Adding a powder-coated finish can provide another layer of protection and a specific color or appearance. This combination is commonly called a duplex system. For manufacturers considering powder coating galvanized steel, the key is to plan the surface preparation and finish requirements together.
Start with the Part’s Condition
Before production, share what the parts are made of, how they were galvanized, and how they have been stored or handled since galvanizing. Surface condition can vary, and that affects preparation. Let your coating partner know whether the parts are new or previously exposed, and flag any visible oxidation, residue, or damage.
The American Galvanizers Association’s guidance on preparing hot-dip galvanized steel for powder coating explains why preparation should be suited to the galvanized surface and coating system. Avoid assuming that one preparation method fits every galvanized part.
Confirm the Required Finish and Performance
A color name alone may not fully describe the finished-part requirements. Confirm the powder type, color, gloss, texture, coverage, and any inspection criteria. If the coated part must meet a particular specification or operate in a demanding environment, include that information early.
Also discuss how the part will be used and handled after coating. Assembly points, contact surfaces, and tight tolerances may affect masking and acceptable coating boundaries. Drawings, photos, and representative samples can help clarify those details before production begins.
Discuss the Curing Process
Powder coatings are cured with heat. Because galvanized steel and powder systems have their own process considerations, the coating plan should be reviewed with the powder supplier and preparation provider. The American Galvanizers Association discusses thermal pretreatment as one approach that may help reduce outgassing concerns, depending on the materials and process.
Do not rely on a generic bake instruction. Confirm the applicable preparation guidance, powder manufacturer’s recommendations, and project specification for the parts in question.
Share Details Before Requesting a Quote
When requesting an industrial coating quote, provide drawings, dimensions, quantities, substrate and galvanizing details, finish requirements, and any critical masking or inspection needs. Clear information helps the finishing team assess the project and identify questions before the parts enter production.
New Finish, Inc. provides powder coating services and surface preparation for commercial and manufacturing projects. To discuss your parts and requirements, contact New Finish.