Surface Preparation: Why Cutting Corners Is Costly

Up to 80% of premature coating delamination is associated with surface preparation rather than the coating material. Even a certified product applied at the specified thickness can fail after the first thermal cycle if mill scale, salts or oil residue remain beneath it.

Surface preparation grades

• Sa 2 — standard abrasive blast cleaning for dry indoor environments
• Sa 2½ — the standard for most industrial facilities and aggressive environments
• St 2 / St 3 — power-tool cleaning where abrasive blasting is not feasible at an operating facility

Checks before priming

• Surface profile roughness matched to the specific primer, not estimated by eye
• Dust-free surfaces with no salt contamination
• Substrate temperature at least 3°C above the dew point
• Relative humidity within the permitted application range

A common mistake

The most common on-site mistake is a delay between cleaning and priming. Prepared steel can begin to oxidize within hours, so work is organized in sections: each area is cleaned and primed during the same shift.