Surface Preparation
Surface preparation is a critical step in ensuring the longevity and effectiveness of coatings applied to metal surfaces. Properly preparing a surface enhances coating adhesion, optimizes resistance, and helps achieve the desired lifespan of the project. The specific requirements for surface preparation can vary based on factors such as the substrate material (e.g., aluminum, steel, concrete), the type of coating (e.g., paint, rubber, metallization), aesthetic preferences, and environmental considerations.
- SSPC (The Society for Protective Coatings): Establishes standards for coatings that protect industrial and marine structures.
- NACE (The National Association of Corrosion Engineers): Focuses on corrosion prevention and control throughout various industries.
- ISO Standards: Provides international guidelines for the best practices in corrosion protection, encompassing over 225 standards related to paints and varnishes.
Applications
When preparing surfaces, it is essential to first assess the initial condition of the surface along with the desired outcomes. This includes defining the following:
Initial State: Refers to the existing conditions, which may range from no rust to uniform rust or cavities.
Desired State : Various levels of surface cleanliness exist, categorized mainly by ISO 8501 or SSPC VIS standards:
- SA3 – SP5: White metal - visually clean steel (99%)
- SA 2.5 – SP10: Near white - very thorough blast cleaning (96%)
- SA 2 – SP6: Commercial - thorough blast cleaning (80%)
- SA 1 – SP7: Brush-off - light cleaning by brush
Characteristics Required
For effective surface preparation, several characteristics need to be considered, including roughness and profile attributes:
Roughness Measurements
- Rmax: Maximum height difference between peaks and troughs.
- Rz: Average of maximum heights over a specified segment.
- Ra: Arithmetic mean of all deviations in the profile.
- Peaks Count: Evaluates the density of peaks, crucial for assessing coating adhesion.
Additional parameters like Rsk (degree of skew/symmetry) and Rku (sharpness/kurtosis) are significant in determining the suitability of the surface for coating applications.
Most Suitable Products
Shot Blast Wheels
Our range of products for shot blast wheels (commonly referred to as Wheelabrators) is designed to enhance recycling, cleanliness, and efficiency. Suitable options include:
High Carbon Grit (GP, GL, or GH hardness, size G50 – G18)
This grit effectively removes surface scale while preparing an optimal profile for strong adhesion.
High Carbon Grit (GL or GH hardness, size G80 to G25)
Known for its chisel effect, this grit efficiently cleans surfaces and prepares them for coating, with the ability to be reused multiple times.
Garnet
A natural and non-metallic abrasive suitable for both waterjet and shot blasting applications. It is environmentally friendly, free of silica and iron, and can be recycled multiple times.
Most Suitable Products
Air Blast Applications
For air blasting (or sandblasting) applications, our products include: