Which blast-cleaning level represents the lightest surface preparation?

• A. Brush Off
• B. White Metal
• C. Industrial
• D. Near White Metal

Answer: (A)

Brush-off blast cleaning represents the lightest surface preparation level. This level is just enough to knock off the loose surface contaminants—think dirt, paint flake, and loosely attached rust—without removing all corrosion products or fully exposing fresh metal. The surface after brush-off is still visibly coated or roughened and may show some staining or slight corrosion residues. It’s chosen when the coating system to be applied can bond to the remaining residues or when there are constraints on time and cost that don’t justify more aggressive cleaning.

As you move to heavier levels, more corrosion products and old coatings get removed, yielding a brighter, cleaner metal surface closer to bare metal. Choosing the appropriate level depends on the coating spec and service conditions; brush-off is the lightest, with more aggressive options used only when the coating system requires a cleaner, more thorough prep.