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You’ve coated your metal surface with a Cortec® direct-to-metal (DTM) coating. You relax in the confidence of good corrosion protection. Then, a few weeks later, you see the coating peeling off, compromising the protection you thought you had. What went wrong? The problem may be poor adhesion on a specialty metal substrate. The solution? Start with VpCI®-373 Wash Primer.
Adhesion Challenges on Specialty Substrates
While most Cortec® Coatings can be applied DTM on carbon steel surfaces, some metals such as aluminum, galvanized steel, stainless steel, and other plated surfaces are difficult for most paints and coatings to adhere to. If adhesion fails, the coating fails, making proper surface prep vital. Common methods for improving adhesion on galvanized steel include acid etching or the use of lead/zinc/chromate primers. Chromate pretreatment and/or conversion coatings can be used on unpainted aluminum. However, Cortec® prefers the worker-friendliness of applying a water-based wash primer.
Water-Based Corrosion Inhibiting Wash Primer
VpCI®-373 is a fast drying, water-based acrylic wash primer that provides phenomenal adhesion on tough-to-adhere-to surfaces including aluminum, galvanized steel, and stainless steel. It offers multi-metal protection with a complex mixture of corrosion inhibitors, making it a competitive alternative to industrial grade solvent borne systems and/or those with heavy metals. VpCI®-373 should be applied at 0.5-1.0 mils (12.5-25.0 µm) DFT, allowed to cure for 72 hours, and sanded before applying a topcoat of choice.
Make Your Coating ‘Stick’ to Metal!
Next time you paint a specialty metal substrate, make sure you get the coating to “stick” by applying a base primer of VpCI®-373 for good adhesion. Contact Cortec® for further support when painting galvanized steel and aluminum surfaces.
