Blast materials

The sandblasting procedures can be divided into the following major groups:

• Deoxidizing sanding (derusting) for metal structures (bridges, iron structures of buildings, tanks, pipes, etc.). Surface preparation to remove rust before the protective coating is applied.
• Scaling: removal of scale from semi-finished products produced with machining, such as disks, tapes, wires, pipes, forged and heat-treated parts.
• Cleaning: Cleaning of casts (cleaning the casts from the mould’s sand and scale), preparation and cleaning of soldering and welding spots, cleaning of welds, removal of old paint and other coatings.
• Sanding for surface finishing.
• Roughening: various metallic or non-metallic coatings (sprayed metal, rubber, etc.). Increasing their bonding strength.
• Fine sanding: elimination of the roughness of previously fine-treated surfaces – caused by use
• Finishing sanding: elimination of the roughness and scratches of the machined surfaces
• Matting: meeting the needs for decoration, as well as eliminating glare from the parts of optical devices

Grits used for sandblasting

The effectiveness of cleaning is determined by the number of particles per unit area at a given moment, their impact speed and mass, as well as their edges.
Based on the composition, two groups of materials can be distinguished:

• man-made blast materials;
• blast materials of natural origin.

The artificial grits include:

• metal grits,
• noble and standard corundum particles,
• silicon carbide,
• glass pearls and glass chips,
• slag,
• blast materials from organic (cut plastic) and artificially produced inorganic materials.

The materials of natural origin include:

• Quartz sand;
• Basalt chippings;
• Sand;
• Ground stones of fruits.

The blast material can have the following shapes:

• Round,
• Pellet-shaped,
• Angular,
• Cylindrical,
• Rounded,
• Concave,
• Column.

Based on its hardness, the material can be:

• Hard,
• Soft.

The most commonly used scale is the Mohs hardness scale to specify hardness. It is based on the so-called connection hardness that shows which mineral scratches the other.

Corundum

Corundum is a blast material produced from aluminium oxide. It has excellent hardness and the edges are renewed during the sanding process. There is standard corundum and inert corundum. 20-96% of the standard corundum is blast material with aluminium oxide content; this number is 98% for the inert corundum. The inert corundum can be used for cleaning stainless steel, for glass matting, stone grinding, and for cleaning of wood, plastic, hard metal, etc. The inert corundum particle can be used for sanding equipment using turbine and compressed air; for sanding cabin processes as well as for free-jet surface treatment or for closed cyclical process provided by a vacuum unit. The electro corundum particle used for sanding does not contain any free silica and therefore it does not cause silicosis. The particles, due to the melting production technology, are monocrystals of homogeneous structure, and have identical shape due to the special milling and grinding techniques.

1. Aluminium oxide particles (Corundum):

White, neutral pH, insoluble in water, does not contain any heavy metals or toxic substances.

• Hardness: MOHS 9
• It's crystal have extremely favourable cutting edges
• Cycle time: 6-8 times
• Packaging: in 25 and 50 Kg bags

2. Glass particles:

Universal blast material from the recycling of glass. Greenish grey, PH neutral, insoluble in water, does not contain any heavy metals or toxic substances./p>

• Hardness: MOHS 6
• Shape: rectangular
• Cycle time: 3-4 times
• Packaging: in 25 and 40 Kg bags

3. Glass pearls:

Micro glass pearls. White, neutral pH, insoluble in water, does not contain any heavy metals or toxic substances.

• Hardness: MOHS 6
• Shape: round
• Cycle time: 4-5 times
• Packaging: in 25 Kg bag

4. Sharp steel grits:

Sharp steel grits.

• Cleaning of surfaces (scaling, rust removal, cleaning)
• Preparation for enamelling, painting and coating
• Rough sanding and matting

GP: Becomes round during work, breaks into spherical segments during fatigue fracture.

GL: The edges become round during work, break into sharp pieces of debris during fatigue fracture.

GH: It remains sharp during work, breaks into sharp pieces of debris during fatigue fracture.