Grit blasting

Grit Blasting Using Air and Turbines to Clean and Polish Metals

Grit blasting is a method used to clean, polish, and reinforce metals. It is used in various industrial areas, including the aeronautics, marine, metallurgy, construction, railway, and automotive sectors.

Grit blasting relies on a mechanical process that uses a turbine to create an abrasive effect on the surface, removing impurities. Grit blasting is performed before surface treatment, especially because it:

• cleans and descales the surface;
• adds roughness to increase adherence of the paint;
• reduces maintenance costs and increases the duration of the coating.

Air or Turbine Grit Blasting: Application Techniques

Two technologies are adopted for grit blasting: turbines and air.

Turbine Grit Blasting

This technique is an airless grit-blasting process that uses a centrifugal turbine to push the abrasive material onto the surface. It is a very effective, high-speed process with very quick work cycles, which is why it is the technique chosen by the Argos Group.

Given the large amount of high-speed abrasive material (up to 1000 kg per minute), turbine grit blasters are suitable for cleaning metals of rust, scale, and dirt, or for large surfaces.

Air Grit Blasting

Also known as an air cannon, the abrasive material in air grit blasting is pushed directly onto the surface using compressed air.

Adding water to the abrasive material results in a specific type of grit blasting called wet grit blasting. In both cases, the dispensers may be fixed or adjustable (either manually or using automated systems).

Sandblasting and Grit Blasting: The Differences

The term grit blasting is often associated with sandblasting (and vice versa), but while both are used to clean and polish metal surfaces, there are some substantial differences in their type of operation and application.

Sandblasting is a very versatile technique that can be adapted to different needs, but for large metal or extended surfaces, grit blasting is much more effective.

The real difference, however, lies in the machinery, abrasive materials, and worker expertise.

The Advantages of Grit Blasting

Grit blasting is used in various industrial sectors with notable advantages. Let’s learn about them.

• It removes corrosion: Rust or limescale that forms on a surface lead to corrosion that can damage the materials over time. Grit blasting removes corrosion, increasing the life of materials.
• It prepares surfaces: Paints adhere better to surfaces treated with grit blasting compared to normal metal surfaces.
• It highlights defects: The grit blasting process highlights each imperfection on the surface of the material subject to processing. It can therefore be removed immediately so it does not become a problem in the future.
• It respects the environment: Grit blasting relies on abrasive granules, eliminating the use of toxic chemical substances used to clean the base materials. The powder created in the process is immediately extracted with a specific machine.
• It reduces times: Cleaning and polishing a surface with traditional methods may take a long time. With grit blasting, processing times are reduced by 75%, with clear advantages for production processes.

Abrasive Materials Used in Grit Blasting

The success of a grit blasting treatment depends above all on the type of abrasive used. Based on the surface and desired result, different materials are available to optimize every process.

Metal grit: For the heaviest cleaning work, metal is the best abrasive. In particular, the grit has a very marked angular shape. Argos only uses this process.

Glass microspheres: A softer abrasive for delicate surfaces. These are indicated for car bodies, the removal of rust or paint, or to polish stainless steel and cast iron.

Aluminium oxide: Ideal for hard surfaces that require light polishing. It is also inexpensive and can be reused.

Plastic: Used to create soft, light abrasive materials for quick, safe grit blasting. It rounds fibreglass, brass, and aluminium and eliminates mould and paint from delicate surfaces.

Staurolite: This mineral abrasive produces less dust than other materials, allowing the worker to see better during the grit blasting process.

Silicon carbide: Currently the hardest abrasive material on the market, it is available as both a powder and grit. Suitable for heavy work that does not require particularly precise treatments.