1.What are the temporary emergency protective measures?
Clean the scratched area
Wipe the scratched area and the surrounding 5cm area with anhydrous ethanol + non-woven cloth to remove grease and dust (do not use wet cloth!).
Apply passivation isolation agent: Apply a water-based zinc-based repair pen (containing chromate passivation agent) to form a temporary protective film.
Or spray a thin layer of WD-40 rust inhibitor (only in dry indoor environments).
2.How to choose restoration materials?
Epoxy zinc-rich primer + color coating topcoat: Best solution (restore the original coating structure)
One-component zinc-containing repair paint: Simple repair (zinc powder content ≥ 80%)
Two-component polyurethane elastic paint: High expansion joint area (anti-deformation)
3.What is the standardized construction process for permanent repairs?
Surface treatment: Use P240 sandpaper to lightly grind along the scratch direction to form a smooth slope (feathered edge) with a width of 2cm. ◦ Use an electrostatic dust removal brush to remove zinc scraps (metal brushes are prohibited!).
Layered coating (epoxy zinc-rich + topcoat solution is recommended): Primer thickness: wet film ≥80μm (completely cover the exposed area of the zinc layer)
Topcoat matching: Request the original plate color card code for customized coating (color difference ΔE＜1.5).
Strengthen edge sealing ◦ Apply polyurethane sealant (width 3mm) to the edge of the repair area to prevent lateral water vapor penetration.
4.What are the corrosion extension blocking technologies?
Electrochemical monitoring: Paste a corrosion indicator patch at the repair point (color change warning threshold: >5μA/cm²).
Corrosion inhibitor injection: For deep scratches (>50μm), inject volatile corrosion inhibitor (VCI) with a needle
5.What are the prohibited operations?
Directly cover with ordinary paint (destroys the cathodic protection of zinc)
Use acid cleaner (dissolves the passive layer)
Ignore the back plate inspection (condensation water may corrode from the back)