Surface preparation is the single most important factor in coating performance. Studies show that over 70% of coating failures can be traced back to inadequate surface preparation. Understanding the international standards helps you specify the right requirements for your project.

ISO 8501-1 Visual Cleanliness Grades

• Sa1 (Light blast cleaning): Visible oil, grease, dirt, and loose contaminants remain. Rarely specified for coating applications.
• Sa2 (Thorough blast cleaning): Most contaminants removed, but some staining may remain. Acceptable for moderate environments.
• Sa2.5 (Very thorough blast cleaning): Near-white metal. Only slight shadows or streaks allowed. The most commonly specified grade for industrial coatings.
• Sa3 (Blast cleaning to visually clean steel): Completely clean, uniform metallic surface. Required for critical applications.

Surface Profile (Anchor Pattern)

Surface profile is the peak-to-valley height created by blast cleaning. It provides mechanical adhesion for the coating system. Typical requirements:

• Standard epoxy primers: 40-75μm
• Marine and heavy-duty systems: 50-100μm
• Thermal spray applications: 75-150μm

The profile depth is determined by the abrasive type, size, hardness, and blast pressure. Selecting the right abrasive is crucial to achieving the specified profile without excessive consumption.

Need help matching your surface preparation requirements to the right abrasive media? Our technical team can provide a customized solution. Contact us for a free consultation and sample.