What kind of surface treatment is suitable for SPA-H signboards?

Jan 28, 2026 پیام بگذارید

SPA-H as weathering steel, surface treatment is

1.

For fast, uniform reddish-brown patina (avoid uneven natural rusting), suitable for urban/landscape signboards pursuing aesthetic consistency:

(neutral, no acid) → spray water curing (7-14 days) → form dense, uniform patina.

: Patina forms in 2-4 weeks (vs 1-2 years natural rusting), color uniform, no peeling, matches SPA-H's inherent weather resistance.

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2.

Matched with patina (natural/accelerated), for mild coastal/semi-industrial areas to enhance corrosion resistance, retain patina appearance:

: Patina stabilization (2-3 weeks natural aging) → clean dust → spray 2-3 layers of weathering steel transparent sealer (polyurethane/silicone-based, UV-resistant) → air dry.

: Thin sealer (no thick coating), retains patina texture and breathability, prevents patina from being washed away by rain/wind.

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3. Basic Surface Preparation (Mandatory Pre-Treatment)

: Wipe with acetone/alkaline cleaner to remove oil, grease, fingerprints on the surface.

: Sandblasting (SA2.5 grade) for raw steel, or wire brushing for slight rust, remove scale/rust to expose fresh steel surface (foundation for patina formation).

: Grind cutting/welding edges to remove burrs, smooth sharp corners (avoid corrosion initiation points).

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4. No-Processing (Natural Rusting) (For Low-Demand Scenarios)

For rural/non-critical signboards with low aesthetic requirements, only do basic degreasing/derusting, then let it rust naturally outdoors:

: Will have uneven color in the early stage (1-2 years), need to clean surface dust regularly to avoid affecting patina formation.

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●Do not use acid-based rust removers/accelerators (corrode steel surface, cause patina peeling and pitting corrosion)