Bonderized steel is galvanized steel that is processed through a phosphate bath. This provides a corrosion inhibiting, crystalline zinc phosphate, micro-porous surface that promotes adhesion of top coatings. This produces the dull gray color characteristic of Bonderized that provides as an excellent “primer” for painting applications. Phosphate acts as an insulator between the drying action of the galvanized coating and the paint, promoting longer paint adhesion. That is why it has been called “Paintgrip” by the trade. Bonderized material should be immediately painted after installation, as the exposed phosphate coating is prone to white rust.