The task of fast and high-quality cleaning of the surface of any material is of great importance in various fields of activity. For example, this is extremely necessary in car service workshops engaged in painting cars: after preliminary preparation of the body, the paint adheres better and lasts longer. It is also impossible not to mention the need to clean metal blanks from traces of corrosion in industry, remove scale and slag from welds, and much more. In order to carry out work with high productivity and at the same time achieve acceptable economic efficiency, it is necessary to choose the right abrasive for sandblasting.

What is sandblasting

Sandblasting was patented in 1870 by American inventor Benjamin Tilman. If we describe the technology in simple terms, we can imagine the surface treatment process as follows:

• an abrasive powder is selected, specially created or suitable for solving a particular problem;
• a pneumatic compressor acts as an energy source;
• sand, flying out with great speed from a nozzle of a special design along with air, hits the surface to be treated with force.

As a result of such exposure from metal, wood, plastic any dirt and coatings are removed.

Simple and common materials offer the highest economic efficiency of use and the achievable processing results. In particular, the usual sifted river sand. In this case, it is possible to choose in a certain way, so to speak, the characteristics of the working fluid (for example, particle size) in order to obtain the desired speed of work and final surface indicators.

However, if you take sand to work with a sandblasting machine, you should understand that this material has both advantages and disadvantages. The latter are so significant that processing with such an abrasive is prohibited in some countries at the legislative level.

Features of the use of quartz sand

Sand for sandblasting equipment for industrial surface treatment or work in a small workshop can be of a very different type. Apply:

• river, sedimentary type with high fractional uniformity;
• river, alluvial type with a fairly high spread in the size of sand grains;
• career mining;
• quartz of natural origin;
• quartz industrial production.

The types of sand in the list can be conditionally considered an enumeration on the level of abrasive functionality. River alluvial — the weakest. With its help, final work or fine cleaning of surfaces is carried out. Quartz of industrial origin has in its composition up to 90% of solid mineral compounds. This abrasive is expensive, because it is obtained by filtration, sieving with the separation of only certain fractions of natural sand.

Completes the table of hardness completely artificial material. Quartz sandobtained by crushing crystals, is characterized by high hardness, increased cleaning ability due to the pronounced shape of the particles with many sharp corners.

Important! The use of any sand leads to the destruction of individual elements of the abrasive mixture. Roughly speaking, extremely fine dust is formed. It enters the respiratory system and causes silicosis, disrupts the operation of various equipment.

Therefore, sanding must necessarily be carried out under controlled conditions. For example:

• with the obligatory equipment of personnel with respiratory protection equipment, carrying out work away from complex equipment;
• processing in closed chambers;
• with air extraction from the abrasive jet ejection zone with its subsequent filtration.

Advantages of the abrasive

Despite the difficulties of working with sand, this particular material is one of the most applicable for sandblasting. It has the following advantages:

• inexpensive and very accessible;
• has low strength indicators, carries out sufficiently fine processing, which reduces the risk of irreversible damage to the surface;
• causes little harm and prolongs the life of the sandblasting nozzle;
• can be used for surface treatment of non-ferrous metals and soft alloys.

To some extent, the dignity of sand can be considered possibility of reuse. After sandblasting, the remaining abrasive can be sold or used independently in construction. For example, for the preparation of a cement-sand mixture. Some grades of raw materials are sievable and can be reused for the sandblasting process.

Disadvantages of sand

Sand also has tangible disadvantages:

• the formation of a huge amount of dust, which is a hazardous factor of production, requiring the employer to pay special wages to personnel;
• abrasive consumption for processing one square meter of surface is huge;
• during operation, visibility is reduced due to a large amount of dust, and as a result, the operator’s ability to accurately perform fine processing;
• additional costs are required for filtration, collection and disposal of huge volumes.

Despite these shortcomings, this abrasive is widely used. Mainly for reasons of availability, low cost and long nozzle life. However, to carry out processing with complex requirements for sandblasting, sand of industrial and artificial origin or other abrasive materials is needed.

Other abrasives for sandblasting equipment

Sandblasting can produce a wide variety of specific requirements. For example:

• thick removable layer;
• low rigidity, viscosity of the coating deposited on the surface to be cleaned;
• high strength of an unnecessary layer on the material;
• deep penetration of impurity particles into the structure of the processed material.

This list is far from complete. However, it gives a glimpse of cases that may arise in the work of a sandblaster. For each of them, qualified personnel can choose one or another special abrasive.

Nickel slag

This material is a product of metallurgy waste processing in the production of nickel and slag. The abrasive is different:

• high hardness;
• complex shape of particles;
• less than 1% quartz content;
• increased mass of particles compared to any quartz sand.

Nickel slag is the smart choice if you need a reasonably gentle finish while reducing occupational hazards. During operations with this material, little dust. In addition, nickel slag can be screened and reused. This looks even more advantageous if we take into account the low percentage of destruction of abrasive particles and, consequently, insignificant losses.

Important! Sift and reapply nickel slag up to 3 times.

Cooperslag

This abrasive is very similar in properties to nickel slag. This is a product of the processing of metallurgy slags formed during the production of copper. Differences from nickel slag in the following:

• the mass of cooper slag particles is high, the impact on the surface is more intense;
• the possibilities of recovery (reuse) are lower, the cooper slag particles are less durable and are strongly destroyed.

Advice! Cooper slag, which is also called vitriol slag, is a reasonable alternative where fast removal of hard coatings is required, which is difficult to handle with ordinary sand.

plastic granules

Plastic abrasive is made resin based. These are melamine (forms a decorative surface of chipboard furniture boards) and amino-aldehyde resins. Both compositions have low strength, therefore, extremely fine cleaning is carried out with their help. With this process, no harm is done to the main surface of the processed material.

With the help of plastic granules, wooden, plastic, thin metal products are cleaned. Mainly restoration workwhere it is impossible to use chemically active substances, solvents. The industrial use of plastic abrasives is the cleaning of cultural monuments, antiques and collectibles, rare items.

Glass granules

glass bead processing widely used in industry. With her help:

• gentle cleaning of the surface;
• processing is achieved without changing the color of the material and its physical properties;
• allows you to get a surface suitable for electroplating operations;
• controlled removal values ​​are obtained, which is of great importance in high-precision processes of mechanical engineering, optical and other instrument making, and watchmaking.

Glass shot, combining the properties of high rigidity and smoothness of particles, is extremely little destroyed. In addition, the characteristics of the abrasive make it easy to remove impurities from it after use. Thanks to this, glass shot and granules for sandblasting can be reapply up to 35 times.

Other types of granules and shots

In order not to dwell on each abrasive in detail, it is worth mentioning only the key properties and features of the use of different types of shot in sandblasting.

1. Ceramic granules and shot in general, they are used in the same areas as glass. They show the lowest degradation rates, so the abrasive can be reused up to 500 times.
2. Chipped cast iron and steel shots are applied to intensive influence on a surface. They are used to increase adhesion or local processing, for example, profiling, notching.
3. Cast steel and cast iron shot are used not only for cleaning surfaces, but also for strengthening them by impact (hardening), they are used for processing before applying electroplated coatings.
   
4. Shot from stainless steel used for cleaning special alloys, non-ferrous metals. This abrasive has a side effect: the treated surfaces, due to the transfer of the smallest particles, acquire protection against corrosion or increase their own parameters.

Each type of shot has recommendations for use. In some cases, extremely high economic efficiency of sandblasting is achieved. In particular, despite its significant cost, ceramic shot is very economical, since it is used up to 500 times.

Natural stone abrasive

Individual countries with sources of extraction of natural stone with high rates of rigidity and brittleness offer on the market garnet. This is sand from crushed pomegranate. When sandblasted, it does not generate much dust. In addition, it is distinguished by a complex shape of particles with many sharp edges, which guarantees an intense, but rather soft effect on the target surface.

In terms of abrasive characteristics, garnet bypasses quartz sand, nickel slag, and cooper slag. Therefore, it is widely used.

Advice! For high economic efficiency, this material is recommended to be used in chamber conditions, with collection and recovery systems. Dust-free cleaning systems show excellent results.

Electrocorundum

Electrocorundum is deliberately placed at the end of the list. This abrasive has record hardness. According to its properties, it is in the 2nd place in the evaluation table, second only to diamond. The use of electrocorundum shows extremely high economic efficiency.

Abrasive can be collected and reuse with virtually no waste. This does not reduce the intensity of the impact on the treated surface. Electrocorundum particles have a complex shape with many sharp edges, the edges of which have the ability to self-sharpen.

Important! The market offers both primary, smelted electrocorundum, and restored. The latter is made from fragments of abrasive wheels and other materials. It is slightly inferior to virgin, may contain impurities, but is characterized by a lower price and therefore is attractive for many sandblasting tasks.

Due to its unique hardness properties, this abrasive can be used to affect almost all materials. They can matte or engrave stone, glass, cut metal, process ceramics.

Factors affecting the choice of abrasive

Experienced sandblasters carefully analyze the capabilities of their tooling, as well as the characteristics of the target surface, to select the abrasive. This makes it possible to achieve not only excellent results, but also to improve economic performance, increase the life of the nozzle and other wearing components of the installation. The following parameters are being studied.

1. The layer of coating to be removed or the nature of the contamination. The level of strength is being studied. An error in choosing, for example, a soft abrasive for a viscous or hard surface will either lead to wasted time and materials, or to a poor work result.
2. The hardness of the target material. The surface of the product must not be severely damaged. Therefore, the selected abrasive must be combined in properties with the base to be cleaned.
3. Target characteristics of the machined surface. If they are not regulated, any hard abrasive can be used. If the surface must be smooth, without dents, chips, it is recommended to choose the working fluid of the appropriate class.
4. Work productivity. Abrasives of complex shape (electrocorundum, crushed quartz sand, nickel slag) guarantee the intensity of impact and the speed of removing coatings.

The last thing that a diligent owner must take into account and, if possible, provide is collection and recovery of waste abrasive material. This allows not only to dramatically improve the economic efficiency of operations, but also to protect personnel and tools from dangerous factors.

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Areas of application of abrasive materials

Sandblasting is widely used today. For different types of activities, individual types of abrasives show optimal results.

1. At building cleaning from decorative colorful coatings, rust of metal parts, sand is excellent. Before using the abrasive, it can be sieved to obtain the desired fraction and good final productivity.
   
2. Copper and aluminum products perfectly cleaned, even in a small workshop, using quartz sand with granules up to 0.3 mm in size.
3. Varnishes and paints from metal products fractions up to 0.6 mm can be removed with sand.
4. Clean off rust and scale from blanks rationally with quartz sand of industrial production or natural material of coarse fraction up to 1.6 mm. Even larger particles (including other abrasives) can remove bitumen, welding scale and other thick coatings of low strength.
5. car body it is recommended to process with steel, cast iron shot, cast or cast improved.
   
6. Works on stainless steel surfaces carried out with glass granules or stainless cast shot.

Modern work (quite popular and fashionable) for applying patterns and matting zones on glass is carried out with special abrasive mixtures based on quartz sand. The particle size is extremely small. Separate process — tempered glass processing. Its high strength surface is processed only with electrocorundum.

As a conclusion

The above description of the sandblasting process is rather arbitrary. In practice, there are dozens of varieties of ongoing operations. Along with air, liquids are used. Under certain conditions, the sandblasting machine can be used for cutting various materials, finishing the edge in the cut zone, and solving other problems. Even such a brief description of the possibilities shows how important it is to choose the type of abrasive and carefully analyze all the parameters of the upcoming processing operation.

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