Steel structure processing enterprises pursue efficiency and long-term durability. As a professional manufacturer, we provide a detailed explanation of a standardized coating system centered on epoxy zinc-rich primer, helping your products achieve a corrosion-resistant lifespan of over 10 years while shortening construction periods. In the steel structure manufacturing industry, epoxy zinc-rich primer is widely recognized as the “anchor” of heavy-duty anti-corrosion systems. It provides a dual defense for steel substrates through sacrificial anode cathodic protection. But how can its maximum effectiveness be achieved?
1. **Foundation of Foundations: Sa2.5 Grade Blasting**
Epoxy zinc-rich primer has extremely high requirements for substrate preparation.
Requirement: Sandblasting must be performed to achieve Sa2.5 grade, leaving the metal surface with a slight “rough” texture.
Reason: This significantly increases the contact area, enabling electrochemical reactions between zinc powder and steel, eliminating the risk of paint peeling.
2. **Core Parameters: Avoid Blindly Pursuing High Zinc Content**
Standard: Higher zinc content is not always better. Excessive zinc powder can cause the paint film to become brittle and reduce adhesion.
Recommendation: For ordinary steel structures, epoxy zinc-rich primer with a national standard zinc content of 60%-70% offers the best balance of cost-effectiveness and workability.
3. **Efficient Coating Process (Recommended Solution)**
To improve workshop turnover, we recommend the following coating system:
Primer: Epoxy zinc-rich primer (dry film thickness 60-80 microns) — provides cathodic protection.
Intermediate: Epoxy micaceous iron oxide intermediate paint (dry film thickness 100 microns) — increases film thickness and shielding properties.
Topcoat: Polyurethane topcoat (dry film thickness 60 microns) — protects the primer and intermediate layers while providing decorative effects.
4. **Construction Pitfall Avoidance Guide**
Mixing and Stirring: Zinc powder has high density and tends to settle easily. During spraying, a pressure tank with a stirring function must be used throughout the process.
Recoating Interval: After applying the epoxy zinc-rich primer, it is recommended to apply the intermediate coating within 24 hours to prevent zinc salts from forming on the surface, which could affect adhesion.
Conclusion: Standardized steel structure coating is a hallmark of corporate quality. Choose our factory-direct high-performance epoxy zinc-rich primer to ensure every steel structure product you produce withstands the test of time.