To keep the patina color of Q355NH weathering steel screens stable, uniform, and not getting darker or mottled over time, here's a clear, practical maintenance method:
1. Apply a transparent matte protective coating (most effective)
Once the screen reaches your favorite color (usually deep chocolate brown):
Use matte acrylic varnish, polyurethane clear coat, or special weathering steel protective oil
Isolates air, moisture, and UV rays → stops further darkening and locks the color
Reapply every 3–5 years
2. Regular gentle cleaning
Rinse with clean water every 3–6 months to remove dust, leaves, and dirt
Use soft cloth or soft brush only; do not scrub hard
Avoid high-pressure water guns and strong acid/alkali detergents
3. Prevent water retention and rust streaks
Ensure good ventilation and drainage on the screen surface and frame
Avoid long-term waterlogging in gaps or corners
This prevents light water stains and dark vertical streaks
4. Avoid contact with corrosive materials
Do not let cement, lime, soil, or wet wood stick to the surface
Use rubber gaskets to isolate from stainless steel, aluminum, and other metals
Keep away from chemical fumes, oil stains, and strong acid/alkali environments
5. Timely minor repairs
For small scratches or uneven color:Lightly sand → spot-spray a little weathering steel accelerant → re-coat transparent finish
