Grinders for concrete: Features of the tool and review of Dnipro-M models

In construction and renovation, there is often a need to work with concrete - cutting, trimming or grinding it. Several tools are used for this, and one of them is a grinder. Not every angle grinder can handle concrete, so it is important to understand the features of the tool and its capabilities. In this article, we will help you choose an angle grinder for cutting concrete, describe what characteristics this tool should have, and also make a brief overview of our angle grinder models.

Features and choice of grinder for working on concrete

An angle grinder is a versatile tool that can perform many tasks. The grinder copes with a wide range of materials, including wood, metal, stone and, of course, concrete. It should be noted that there is no separate category of grinders that are suitable exclusively for one material, therefore there are no grinders that are designed specifically for concrete. However, you cannot use any grinder to work with concrete, since there are models whose power and capabilities are not enough for this.

Grinder disc for concrete

You immediately need to choose the right circle for concrete - its diameter and type are of particular importance.

Disc diameter

As for the size of the circle, a 125 mm disc diameter may be sufficient for simple work, but a 230 mm disc is useful for cutting large blocks of concrete. Each grinder has a limit on the maximum diameter of the disc to be installed, so you should decide on the disc before purchasing the tool.

Disk type

Concrete diamond blades and turbo diamond blades are used for cutting concrete. These types are not interchangeable and have different levels of practicality.

• Segmented circles are more affordable, but have less strength. They are chosen if the work to be done is simple and the disk will not be subject to too much load.
• Turbo diamond discs with a wave casing have a high cost, but differ from others in their maximum safety margin.
• You can also find turbo diamond discs without a wave casing, which occupy an intermediate position.

Another criterion for choosing a disk is the method of attaching the carbide brazing. It can be laser welded (suitable for dry cutting and high productivity) or using silver solder (suitable for wet cutting).

The disc must be suitable for the grinder in diameter. Moreover, this means not only the outer diameter, but also the diameter of the mounting hole. The rotation speed that the disk can withstand must be higher than the maximum number of revolutions that the tool can produce - this will guarantee that the disk does not deform during operation.

Grinder power for concrete

The power of the angle grinder must be selected based on the parameters of the disk - the larger the disk, the greater the torque the grinder will have and the less load on the engine will be. It should be noted that grinders with a power of less than 1 kW do not have the necessary engine protection for working with concrete and belong to the household category. They are poorly suited for working with concrete, especially for a long time.

Cutting without dust, how to saw

In the text above, two main methods of cutting concrete have already been mentioned - wet and dry.

Wet method, features. The wet or wet method is recommended for high-quality and productive cutting of concrete. Cooling the working nozzle and the surface of the cutting zone with water will allow you to work without stopping for additional time to cool down the equipment. In addition, the water will remove dust, and the technological process itself will be carried out without a large amount of dust.

If you use a grinder as a tool, then to reduce dust you should moisten the diamond disc and the cutting surface with water. The help of a work colleague who will water the cutting area from a plastic bottle will be very helpful.

Attention: water should not get on the angle grinder.

The wet method can be used without problems in buildings under construction where there is no risk of flooding of neighboring rooms. When carrying out renovation construction work in residential premises, for example, organizing an additional doorway, the wet cutting method is fraught with wet walls and electrical short circuits.

Angle grinder Makita GA 5030 for cutting concrete. Photo 220Volt

Dry method, features. Dry technology will allow you to avoid the bad consequences of the wet cutting method. Here the disks are not cooled by water, so it is quite possible to make an additional opening in a small apartment wall using this method. In this case, the grinder will have to be turned off very often to cool down, and the process will take quite a lot of time. The use of a special construction vacuum cleaner is mandatory for dry cutting. To wait until the dust settles is to initially condemn the work to a fiasco. You will also have to put up with frequent replacement of disks - they will wear out quickly.

When carrying out work in an apartment to construct an opening in the wall using dry cutting, the following stages of work should be followed:

• the redevelopment project must be approved by the relevant authorities;
• make a thorough marking of the boundaries of the opening, taking into account the presence of utilities, provide for the presence of fittings;
• cut the perimeter of the borders on one side;
• drill the corners of the opening;
• Taking into account the drilled holes, cut the boundaries of the opening from the reverse side.
• dismantling cut concrete with cutting into pieces with a weight allowing them to be transported;
• strengthen the opening (this stage must be specified in the agreed project) with metal corners or a channel.

Review of grinders for concrete Dnipro-M

The Dnipro-M brand offers several models of angle grinders that differ in their characteristics, but all cope successfully with concrete.

GS-120S

This is the first of two short-handled models that are suitable for working with concrete. When combined with the letters "GS" in the model name, the "S" stands for "short". The short handle is convenient because it reduces the size and weight of the tool - with excellent functionality, the grinder will be convenient to work with, as well as store and transport it.

The model is perfect for everyday tasks, but also copes with professional-level tasks. The power of 1200 W is enough not only for cutting metal (reinforcement - up to 18 mm, sheet metal - up to 5 mm), but also for working with concrete. You can adjust the spindle speed from 3000 to 10500 rpm.

The presence of a soft start function will protect against a jerk at the beginning of work, and protection against restarting guarantees safety during a short-term power outage (after reapplying voltage, the angle grinder will not start working even when the power button is pressed). The quick-release casing ensures a quick change of its position.

GS-140SE

Another model with a short handle. It is distinguished from the GS-120SE by increased power (1400 W) and the presence of a speed support function. The power of 1400 W is quite enough for cutting metal (reinforcement - up to 25 mm, sheet metal - up to 8 mm), cutting and grinding concrete.

The price of the model is fully justified by its capabilities. Speed ​​support allows you to work with any materials, including concrete, even at first speed. At the same time, the disk rotation speed will remain constant even under heavy load, which gives 10% better performance compared to conventional models.

You can press the grinder onto the surface or work barely touching the material - the disk will rotate at the same speed. This helps to achieve high-quality results even if you have no experience working with the tool.

As in the previous model, the disc rotation speed range is from 3000 to 10500 rpm. You can select the desired value for working with a specific material using the speed control function. Soft start and restart protection increase operating safety.

GS-160SE

One of the most effective models of grinders Dnipro-M for working with concrete. Its efficiency is ensured by high power (1600 W) and Constant Speed ​​speed support system. Being the choice of professionals, this grinder is capable of working up to 12 hours a day, providing the required pace of work. A large number of functions make it easy to cope with complex tasks.

The GS-160SE is capable of working with a variety of materials, cutting rebar (up to 25 mm), sheet metal (up to 10 mm), tiles, stone, brick and ceramics. It also easily copes with concrete, including reinforced concrete. The grinder can be used for grinding concrete with a circle with a diameter of 125 mm.

The Constant Speed ​​function ensures uniform rotation of the disc when working with non-uniform material. Even if you press hard on the grinder, the number of revolutions of the disk will remain stable - the tool adjusts the voltage supply depending on the current number of revolutions.

This model has a built-in speed regulator, which allows you to set the required rotation speed for working with specific materials (the regulator has 6 positions). The Soft Start function protects the operator from jerking when starting work and also prevents rapid tool wear. Safety is further enhanced by restart protection.

The grinder is convenient to work with due to its compact dimensions, short handle and narrowed shape. You can quickly change the position of the protective housing using the quick lock function. Comfort is enhanced by a rubberized additional two-position handle (included in the kit).

GL-145S

The most affordable concrete grinder is the Dnipro-M with a long handle (in “GL” the letter “L” means “long”). The 1450 W power is enough to work with a wide range of materials, including metal, asphalt, brick, slate and concrete. This is the most powerful version of the Dnipro-M long-handled concrete grinders, which work with a circle with a diameter of 125 mm. If you need a universal model for cutting and grinding concrete, but at the same time the tool must have high power, the Gl-145S is the most suitable option.

The speed control allows you to set the disk rotation speed in the range from 3000 to 10500 rpm. This makes it possible to work with a wide range of materials, selecting the optimal rotation speed for each of them. The quick-release protective cover allows you to loosen the clamp and change its position with one movement of the hand, reducing operating time. A bonus of this model is quick access to the brushes.

GL-160SE

A special feature of this model is the combination of a long handle and a speed support function (by maintaining power). It is very convenient to work with it even with little work experience, since the support of revolutions guarantees the same number of revolutions under different loads. As a result, you will get an even cut or a high-quality polished surface.

Power support coupled with a 150mm blade diameter makes it possible to cut concrete to a depth of up to 45mm, which is 10mm more than the models described above could do. The rotation speed range is from 4500 to 10500 rpm; the disk rotation speed regulator is present in the model. This model also has overload protection, which increases the service life of the tool.

GL-240

One of the largest and most powerful variants of grinders for concrete is Dnipro-M. This model is capable of working with discs with a diameter of 230 mm, and its power is 2.4 kW. It can easily be used for gating, working with metal and even reinforced concrete up to 70 mm, and the presence of a rotary handle allows you to do this as conveniently as possible in any position. The price of the grinder is fully justified by the power and capabilities of the tool.

The GL-240 model has gained great popularity among professional builders, as it is capable of performing the entire range of work for which angle grinders are intended. It is often used on construction sites, factories, and for major repairs.

Additional features include a soft start function, which makes it convenient to start working with the tool. When starting the grinder, there is no jerk, since the disk picks up rotation speed gradually. Operator safety is also enhanced by the handle's trigger lock, which prevents accidental activation.

GL-280

The angle grinder GL-280 works with wheels with a diameter of 230 mm. Its power is the highest in the range of angle grinders of the brand - 2.8 kW. This is enough to complete tasks of any complexity. The model is very popular among professional builders. It can easily handle reinforced concrete up to 75 mm and less durable materials. In addition, the grinder can also be used in production - its power ensures high-quality and fast completion of any tasks. Best choice for straight and stand cuts.

Smooth start and protection against sudden activation (trigger locking of the power button) make working with the GL-280 angle grinder safe. After pressing the start button, the angle grinder accelerates gradually, so the operator will not feel a jerk.

Consumables for angle grinders

There are several types of attachments for concrete grinding:

1. Cups. They are discs with a recessed center. The purpose depends on the shape of the working surface:

• with square pads - for roughing with cutting off protruding fragments of concrete;
• with a double segment - for uniform removal of the top layer;
• with boomerang-shaped pads - for final surface polishing.

1. Discs (circles). They have a flat surface with an abrasive applied to it:

• with large and medium-sized diamond chips - for rough grinding;
• with fine crumbs and a cellular structure (turtles) - for polishing.

1. Frankfurt. Special trapezoidal nozzles. Depending on the type and characteristics of the working surface, they are used for grinding or polishing concrete floors.

Quality guarantees

The Dnipro-M brand adheres to internal quality standards that make its products high quality and reliable:

• The engine of each corded angle grinder is protected from overheating, moisture and dust using a three-layer coating with heat-resistant varnish.
• Reinforcing thread and epoxy resin are also used to protect the engine.
• The stator winding is coated with a polymer that protects it from dust, moisture and short circuits.
• The gearbox gears are made of alloy steel (HRC - 61-63).
• Dnipro-M angle grinders use C&U brand bearings (high level of dust protection).
• Dustproof power button.
• The correct size and shape of the impeller allows you to effectively cool the engine.
• The warranty on all power tools of the brand, including grinders for concrete, is 3 years.

All these advantages make the purchase of grinders from the brand profitable and allow the tool to solve a wide range of tasks - from working with wood to grinding concrete. The grinders come with an additional handle. The side handle can be installed on either side of the tool, which makes its use convenient for both right-handers and left-handers.

Grouting fresh screed

This technology is used to create durable, wear-resistant floors in industrial and commercial premises, and hard coverings in open areas.

A concrete grinding helicopter is a manual or self-propelled trowel with a diesel, gasoline or electric engine. With its help, the screed is processed 4-20 hours after installation. This allows the top layer to be compacted; cement-based toppings are used to enhance the effect.

After rough grinding, finishing is performed within 10-16 hours. In this case, a dust-removing impregnation is rubbed into the surface of the concrete. Helicopter processing of fresh screed makes the floor surface smooth and resistant to cracks. For a decorative effect, pigments are used in the topping.

Frequently asked questions about grinders for concrete

How to cut concrete at home?

There is special equipment for cutting concrete - concrete cutters. They have high power and are able to cope with thick concrete parts. Often such equipment allows liquid to be applied to the disc (wet cutting). You can also use a wall chaser to make grooves in concrete. At home, a grinder with sufficient power (at least 1 kW) is quite suitable for cutting concrete - it will be able to cut a piece of concrete that is not too thick or sand it.

How much does a grinder cost for concrete?

Prices for Dnipro-M grinders for concrete vary from 1350 to 3180 UAH.

It is important to know

Modern manufacturers offer a variety of equipment models, so finding a specific model of equipment in Moscow and the regions will not be difficult (as well as companies or specialists who will quickly and efficiently complete the work). But you need to remember some nuances.

Things to remember when cutting concrete:

• Wall saws are not used in multi-storey panel buildings due to the risk of flooding the lower floors with water. The machine is also not suitable for working in confined spaces and when it is necessary to perform small volumes of cutting.
• To reduce noise, you can cut openings in parts (at least 6 parts). The price of the work in this case increases and depends on the number of pieces cut out.
• All holes/openings in load-bearing structures are made only by certified companies and in strict accordance with the rules.
• Legalization of hatches/openings in load-bearing walls requires contacting government agencies with a full package of documents.

Cutting concrete without dust is a difficult task, which can only be partially realized. It is very difficult to completely get rid of dust, but its amount can be significantly reduced through the correct choice of equipment and attachments, cutting method, as well as the use of a construction vacuum cleaner and the creation of special devices for collecting dust.

Which nozzle to choose?

In order to process the coating efficiently, you need to carry out the work slowly, taking into account the nuances. When choosing a nozzle, take into account the type of concrete and the fillers it contains. There should be no holes or bumps on the floor more than 5 mm high.

READ How to Disassemble Grinder Gearbox Video

Abrasive cup attachment for angle grinders

The cost of the work depends on the choice of material on the disk-cup, and the material is selected based on the purpose of the room.

• The best option is a disk-cup with crushed stone metamorphic small fractions.
• If impregnation is applied on top, then use marble or granite chips.

The disc must contain small fractions of strong rocks that will polish the surface of the concrete. They are easy to work with, but more difficult with a disc made of sedimentary gravel. The quality of processing depends on the density of the filler. High density is not recommended, and low density will not allow you to achieve quality.

Preliminary stage

If there are any coatings on the concrete surface, you should try to remove them. You must first level the plane. This can be done using a 3D ruler. If bumps, potholes or holes are detected, it is necessary to increase the number of diamonds. It is necessary to carefully examine the deformation-shrinkage seams and cracks. If there are any, then they need to be sealed and problem areas additionally sanded. In order to check the hardness of the floor, you need to try working a small area with a grinder.

Before you start grinding concrete, you need to make sure that there is no reinforcement or reinforcing metal mesh in the top layer. If such material is available, then it needs to be cut out with a grinder.

Conclusion

To grind concrete surfaces of small areas, it is not necessary to use bulky construction equipment. All work can be done using a manual grinder, for which you should put a special diamond wheel on it. The video in this article will help you find additional information on this topic.

Sources

• https://zamesbetona.ru/obrabotka/shlifovka-betona.html
• https://kvartirnyj-remont.com/shlifovka-betona-bolgarkoj.html
• https://1nerudnyi.ru/shlifovka-betona-bolgarkoj-01/
• https://laminatepol.ru/19524-nasadok-dlya-shlifovki-betona-na-bolgarku.html
• https://stroy-podskazka.ru/instrumenty/bolgarka/nasadki-dlya-shlifovki/
• https://tehnika.expert/dlya-remonta/bolgarka/kak-shlifovat.html
• https://masterabetona.ru/operacii/95-shlifovka-betona-bolgarkoj

Why grind a concrete floor?

Recently, technologically advanced pouring and installation of a concrete floor for laying floor coverings cannot be imagined without grinding. High-quality work will make the coating practical. It will reduce the cost of money and effort on leveling the floor surface, installing parquet or laminate, and does not require periodic restoration.

The cup attachment is used for preliminary preparation of the base for laying new floor coverings

In addition, it provides the following capabilities:

Attention! If a fresh coating is being sanded , then additional steps related to the removal of lime milk are not performed. When sanding an old floor, the old layer is removed.

Grinding is used to provide a flat and smooth surface for treatment with strengthening compounds or coating with paints. In this case, grinding is done on the new coating in two stages:

• After 3-5 days after pouring - pre-treatment.
• After complete hardening of the composition - final processing.

Using a tool with a special disc attachment for grinding concrete on a grinder will solve a number of problems in cleaning and eliminating minor defects:

• Cracks.
• Chips.
• Surges.
• Ripple.
• Notches.

Sanding is used to restore the coating. Especially when leveling work is carried out on an old floor. The first step is to remove the worn layer, and then use an angle grinder. If this is not done, the strength of the leveling layer will decrease.

An unpolished concrete floor absorbs moisture in large quantities. If the coating is located outdoors or in an unheated room, then at subzero temperatures the concrete will freeze, and the moisture in it will increase in volume, which may cause cracks.