I. Selection & System Matching
Q1: Which coating system is best for outdoor exposure and long-term gloss/color retention?
Use a heavy-duty and weather-resistant system: Waterborne Epoxy Zinc-Rich Primer + Waterborne Epoxy Mica Iron Intermediate Coat + Waterborne Acrylic Polyurethane Topcoat.
The zinc-rich layer provides cathodic protection, the mica iron layer blocks moisture, and the polyurethane topcoat offers UV resistance and color stability—ideal for bridges, storage tanks, and exposed steel structures.
Q2: What system is suitable for environments with chemical exposure (e.g., chemical tanks or equipment)?
Select Epoxy Zinc-Rich Primer + Waterborne Epoxy Topcoat for excellent chemical and mechanical resistance. For better appearance and weatherability, an Acrylic Polyurethane Topcoat may be added on top.
Q3: Do coastal or high salt-spray areas require a special primer?
Yes. Use Waterborne Inorganic Zinc-Rich Primer, featuring a denser zinc structure with outstanding salt-spray resistance and cathodic protection. It is highly recommended for ports, coastal zones, and heavy-duty corrosion projects. Ensure proper surface cleaning and rust removal before coating.
Q4: How to balance cost and performance for factories or warehouses with limited budgets?
Choose an Economic Steel Structure System: Waterborne Alkyd Primer + Waterborne Alkyd Topcoat, or a 2-in-1 Primer & Topcoat option (see Q6). These provide basic rust protection with lower construction costs.
Q5: What coatings are suitable for equipment, pipelines, or hardware requiring quick drying and decorative appearance?
Use Waterborne Epoxy Ester 2-in-1 Primer & Topcoat or Waterborne Quick-Dry Protective Paint for faster operation.
If higher aesthetic quality is needed, apply Acrylic Primer + Amino Topcoat for high-gloss and decorative performance.
Q6: Can a “2-in-1 Primer & Topcoat” simplify the coating process?
Yes. A 2-in-1 system such as Waterborne Epoxy Ester Primer & Topcoat eliminates the intermediate coat, suitable for light-duty protection of equipment and hardware. Ensure the required dry film thickness (DFT) is achieved evenly; avoid excessive single-coat thickness or cross-system mixing.
II. Application & Process Control
Q7: What is the required level of surface preparation?
Follow standard steel structure anti-corrosion practices—blast cleaning to Sa2.5 or power tool cleaning to St3, keeping surfaces dry, oil-free, and dust-free. The substrate temperature should be at least 3°C above the dew point before primer application.
Q8: Can different coating systems be mixed or combined?
Not recommended. Cross-system mixing should only proceed after adhesion and weathering tests. Huacheng recommends using complete systems to ensure intercoat bonding and coating longevity.
Q9: What are the recommended application temperature and humidity conditions?
Optimal conditions: 10–35°C and relative humidity ≤80%. Avoid condensation or direct wind. In cold regions, preheat substrates appropriately. Always ensure the previous coat is fully cured before recoating to prevent wrinkling, blistering, or delamination.
Q10: How should film thickness and number of coats be controlled?
Set dry film thickness (DFT) according to protection level:
- Heavy-duty systems ≥160 μm
- Economic systems ≥80 μm
Follow the TDS or project specification. Always check uniformity with a wet film gauge.
Q11: How to speed up drying when the project is on a tight schedule?
Use Waterborne Quick-Dry Protective Paint for non-heavy-duty applications. In heavy-duty systems, strictly observe the specified overcoating intervals to maintain adhesion performance.
III. Performance, Maintenance & Recoating
Q12: How to prevent fading or chalking during outdoor exposure?
Avoid prolonged exposure to acidic or alkaline cleaning agents. Regular cleaning of surface dust and dirt helps delay aging and maintain appearance.
Q13: What should be done if equipment or railings are scratched or impacted?
Conduct local repair following the same system: sanding and cleaning → reapply primer → reapply topcoat, ensuring required film thickness. For large-area damage, recoat with the full system.
Q14: What to do if chemical liquid splashes or contamination occurs?
Immediately rinse with clean water or neutral detergent. If the coating loses gloss or softens, sand the area and recoat using the same system.
Q15: Can the coating be used long-term under direct exposure?
Heavy-duty systems can be used without extra protection. Economic or decorative systems used outdoors should be periodically maintained or overcoated to extend service life.
IV. Packaging, Storage & Environmental Compliance
Q16: Will high or low temperatures during transport affect product performance?
Avoid prolonged exposure to heat or freezing. If viscosity increases or slight separation occurs, restore to room temperature and stir thoroughly before use.
If severe freezing occurs, contact technical support for inspection before application.
Q17: Do the coatings meet export environmental standards?
Yes. Huacheng’s waterborne industrial coatings use water as a diluent, are low-odor, low-VOC, non-flammable, and comply with common environmental standards in multiple countries.
Q18: What are the shelf life and storage requirements?
Typically 6–12 months under cool, dry, and sealed conditions. Conduct a small sample test if beyond the shelf life. Recommended storage temperature: 5–35°C.
V. Troubleshooting Guide
Q19: Why does poor adhesion or peeling occur?
Possible causes include insufficient curing between coats, damp substrate, or incompatible systems. Sand and clean the surface before recoating, avoid cross-system mixing, and ensure previous coats are fully cured.
Q20: Why does premature fading or loss of gloss occur?
Usually due to insufficient UV resistance or inadequate film thickness. Use Acrylic Polyurethane Topcoat with better weatherability and ensure sufficient DFT for enhanced color retention.
Q21: Why does pitting or rust reappear?
Edge or corner film thickness may be too thin, or surface preparation was inadequate. Reinforce coating thickness on welds and corners, and strictly follow the recommended coating procedure.
Q22: Why do sagging or orange-peel effects appear?
Caused by excessive wet film thickness, unsuitable temperature/humidity, or unstable spray pressure. Apply multiple thin coats, adjust spray distance and dilution ratio, and maintain stable conditions.
Q23: Why does whitening occur after drying?
Usually caused by high humidity or substrate temperature near the dew point. Control environmental humidity, ensure ventilation, and extend drying or add gentle heating if necessary.
VI. Additional Notes & Auxiliary Systems
Q24: When is “Waterborne Universal Protective Paint” recommended?
It suits medium-level anti-corrosion needs such as storage racks or ordinary equipment frames. It offers excellent workability and fast drying, ideal for economic projects or temporary protection.
Note: Universal protective paint cannot replace heavy-duty anti-corrosion systems.