Preparing
Surface preparation
Why prepare a surface?
Any metal surface must first be well prepared prior to be coated to ensure optimum resistance of the coating and achieve desired project life.
Many specifications could help you determine the required preparation, and these include, but are not limited to, substrate to be coated (aluminum, steel, concrete…), the coating composition (paint, rubber, metallization, etc.) the aesthetic desired, the environment and all other requirements.
The main ones are:
- SSPC (The Society of Protective Coatings): they create standards for coatings that protect and preserve concrete, steel and other industrial & marine structures and surfaces.
- NACE (The National Association of Corrosion Engineers): standards applied to corrosion prevention and control in industries during the design, building and operation to limit the impact of corrosion.
- ISO: Standards in Corrosion Protection. They have a volume that has more than 225 ISO International Standards that covers the best methods of performance of paints and varnishes of steel substrates:
Applications
Preparing
For surface preparation applications, it is first necessary to define the initial state of the surface, the desired state, the characteristics required of the surfaces and the equipment used for the realization. We can help you define them, but the main ones are:
- Initial state: See specification SSPC VIS 1: guide that describes with the use of photographs the initial surface states.
- Practically no rust
- Rust spots
- Cavities
- Uniform rust
- Desired state: several standard degrees of preparation exists, selected primarily depending on the application, durability, and environment. The main 4 standard levels seen in the ISO 8501 (Link) or SSPC VIS 1 are:
- SA3 – SP5 – White metal – Blast-cleaning to visually clean steel (99%)
- SA 2.5 – SP10 – Near white – Very through blast cleaning (96%)
- SA 2 – SP6 – Commercial – Thorough blast cleaning (80%)
- SA 1 – SP 7 – Brush off – Light cleaning by brush.
Note: cleanliness is expressed as “the degree of cleanliness of an initial surface state”. Ex: The degree of cleanliness SA2.5 on a sheet of steel, whose initial state was C, is C SA2.5”
Characteristics required
Roughness
Among others, roughness is one characteristic to control for any surface preparation application. We have training and tools to help you measure and control these parameters. The shape of the surface (peaks and valleys (troughs)) can be expressed using:
- Rmax: Maximum height between a trough and a peak. It quantifies the maximum height to be covered by a coating.
- Rz: Average of maximum heights of a consecutive segment, in the assessment length.
- Ra: Arithmetic average of all the profile’s deviations.
- Peaks count: number of peaks per length unit enables evaluation of the average width and density of the peaks, which are elements of prime importance in coating adhesion.
- Rsk (degree of skew / symmetry) and Rku (kurtosis / sharpness) are also important factors in coating applications.
Most suitable products
Our product ranges
For surface preparation of steel, concrete, aluminum or other, a complete range of blasting abrasives exist. Whether mineral or manufactured, they each have their characteristics and advantages. One of the first selection criteria is the equipment used:
Shot blast wheels
Our products range for wheel blast machines
Commonly called “Wheelabrator”, wheel blasters have the advantage of recycling, cleaning, and propelling large quantities of abrasive media. However, a full range of media are not suitable for it, including those with a low recyclability rate, except for very specific applications:
High carbon grit (GP, GL or GH hardness, size G50 – G18)
With its chisel effect and a range of varied hardnesses, HC grit blasting will effectively and quickly remove surface scale, detritus and create a profile adapted for a good adhesion.
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ProWheelium™
Premium cast steel grit solution, ready-to-use operating mix, with a very narrow hardness range. It reduces machine wear versus GH abrasives, and helps maintain an optimum and aggressive surface profile, consistency of results with a lower abrasive consumption.
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Surfium™
Premium steel abrasive solution, made of 100% grit with a specific hardness to reduce dust levels and consumption. Surfium is specially designed for the Energy sector or before coating.
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Stelux™ Grit
A stainless steel fully recyclable aggressive media, that can be used alone, or blended with Stelux™ round shot for preparing prior to coating of non-ferrous metals.
Discover MoreAir blast applications
ours products for air blast applications
Whether automated for large-scale projects (railroad, windmills), or for open air application (construction), or in blast chambers fully equipped with a recycling system (Industrial sandblasting), airblasting (commonly referred as sandblasting) is a common process that uses compressed air to propel abrasive media across the surface of your parts. To select the optimal airblast abrasive for your application, we invite you to contact our technical team. Here are the main ones:
High carbon grit (GL or GH hardness, size G80 to G25)
With its chisel effect and a wide range of hardness to choose from, HC grit will effectively and quickly remove surface scale, detritus and create a suitable profile for a good adhesion. Made of recycled steel, abrasive media can be reused hundreds of times, either manually or through a full recycling system.
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Profilium™
Premium cast steel grit, ready-to-use operating mix to simplify process, improve surface consistency and maintain efficiency. In addition to having better visibility and a cleaner environment due to the absence of dust, we can expect up to 20% more efficiency than standard steel grit abrasives. Is also an excellent alternative product to cast iron grit.
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Garnet
A natural, non-metallic abrasive, either for waterjet or for shot blasting, coming from either Alluvial (river, slightly rounded corner) or Hard Rock (crushed, angular). It is generally used to clean metal, cement and other mineral surfaces. Recyclable 2 to 3 times, it is relatively inexpensive and is used mainly outdoors. Among its components we have almandite and ilmenite and it is free of silica and iron, which makes it very safe for operators, respectful of the environment and compliant with the required hygienic and sanitary standards.
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Stelux™ Grit
A stainless steel grit fully recyclable and reusable, aggressive, and iron-free. With it’s high endurance, it can be reused hundreds of times. Rust free, meaning it will leave no ferrous residues on the surface, it is perfectly adapted to airblasting non-ferrous metals, or any application requiring an iron-free abrasive media.
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To be able to select the best option for your surface preparation application, please communicate with one of our specialists