Review of diamond blades and wheels for cutting concrete and reinforced concrete

What is a grinder disc for concrete?

A grinder or a manual grinder is very convenient for cutting ceramics, concrete, and brick. It is only necessary to use a special disc for a grinder on concrete, since corundum and carbide abrasives used when cutting steel or soft stone are not suitable.

To cut a concrete product, you need discs of a special design and a different composition. The cutting element in them is diamond chips, obtained artificially from carbon minerals. The price of these tools is much higher than abrasive wheels for cutting metals.

The disc is based on durable hardened steel that can withstand high temperature loads. Its cutting part is the outer edge containing a layer of diamond crumble. Such layers contain very small technical diamonds distributed throughout the volume.

When cutting, the outer layers are actuated, but the abrasive composition is actuated much more slowly than the mass being cut. After one layer has been triggered, the next one is activated, thanks to which an expensive cutting tool allows you to perform work that is much larger in volume compared to a conventional one.

Tool functionality

Depending on the purpose, the disc for the grinder for concrete is made whole or divided into separate segments. Dividing the working surface into segments helps to increase the cooling intensity of the tool during operation. The cutting edge itself can be made from diamond chips of different grain sizes with different connecting elements. The technology of making the cutting layer also plays a role.

Methods of technological fastening of cutting segments to a steel base, as well as the corresponding functional purpose of the disks:

• soldering with silver solder, the tools are used when cutting concrete in a wet environment, due to which their surface quickly cools and does not peel off from the base;
• laser welding, which makes it possible to obtain highly reliable cutting wheels that can be used when cutting reinforced concrete structures, marble, granite without moisture;
• thermal spraying using a binding agent or geometric closure, which makes it possible to use circles for wet and dry cutting of concrete.

Depending on the dimensions of the concrete products to be cut and what models of grinders will be used, diamond discs are manufactured by industry in various diameters.

Features of cutting with a grinder

After choosing the equipment and the circle for it, before cutting concrete with a grinder, you need to familiarize yourself with the recommendations for carrying out the work:

Cutting cinder block

• The tool must be held with both hands. In this case, if a reverse strike occurs, it can be held, which will minimize the displacement of the cutting line;
• Work should be carried out only on a flat surface so that the person’s balance is maintained;
• The power cord should be located on the opposite side of the drive to prevent accidental damage to it. A cut cord can cause a shock wave from the unit and a short circuit in the electrical network;
• The tool must be held firmly in your hands until it stops completely;
• When changing the place of sawing, the grinder must be turned off so as not to accidentally touch surrounding objects;
• When there is a power outage, be sure to unplug the equipment from the network. This will prevent it from turning on when electricity is supplied without operator control.

Tip: During operation, the discs become very hot, so after turning off the grinder, you should not touch it until it cools completely.

Working with brickwork

Cutting concrete along a line

After the grinder for concrete has been prepared, work can begin.

For this:

• The cutting line is outlined. At the same time, it is advisable to fasten wooden blocks along the line, which will make the cut line more even;
• The grinder is turned on and a cut is made with a depth of approximately 5 - 10 mm;
• The bars are removed;
• A cut is made to the required depth. If the cut is made dry, the procedure should be stopped periodically to allow the instrument to cool.

Carrying out preliminary marking work

The video shows in detail how to cut concrete with a grinder correctly. The process is best performed with the tool cooled.

For this:

• An ordinary spray bottle sprays water directly onto the furrow to reduce the amount of dust;
• Water is sprayed directly onto the disk, in the absence of a nearby power source. This will reduce the heating of diamond blades and extend their service life;
• If it is not possible to spray liquid onto the disc, cooling can be done with air. Periodically, the circle should be removed from the cut and given the opportunity to work in the air.

Working with a grinder with manual cooling of the tool

If you have questions about cutting concrete, or if you want to know how to polish concrete with a grinder and other details on using similar equipment, check out the video in this article.

Types of disks, their features

The industry produces several types of diamond wheels that can be installed on an angle machine:

• with a segmented body;
• turbo diamond;
• wave in a turbo-diamond case.

Diamond wheels of these types are capable of withstanding a very large technological load, designed for cutting reinforced concrete, but the cost of such attachments is the highest. They are divided into professional and household, which is typical for most construction tools. For different operating conditions, they are produced by industry in different designs.

Household diamond wheels

For home purposes, a grinder disc for concrete is also often used, which can be used to cut very hard materials, ranging from ordinary bricks to ceramics and concrete tiles. But they are not very suitable for cutting granite, marble or carving a reinforced concrete base. In addition, tools for household purposes wear out so quickly that they are not used for professional purposes.

Such household diamond blades as “Zubr”, “Sparta”, “Tsentroinstrument” have optimal ratios in the price-quality segment. The external coating on them meets high requirements; with irregular use, they last quite a long time.

It is very important to use diamond wheels in accordance with their intended purpose; they should not be used to cut metal or concrete without proper cooling. To ensure that cutting wheels do not overheat and serve reliably, it is necessary to limit the duration of their switching cycles.

What other diamond blades are there?

For cutting concrete, discs that are made of reinforced materials are used. Their thickness is extremely wide, because then there is much more spraying.

During manufacturing, a layer of diamond sputtering is applied to the surface of the discs, distributed in a ring. This is clearly visible from the side; this edge of the circle is also called a “cup”.

When grinding concrete, structurally complex discs are used. They have a base made of tool steel on which grinding cups are mounted.

Professional circles

For production purposes, professional diamond wheels with diameters from 125 to 350 millimeters are used. Their cost is significantly higher than the price of similar household cutting tools, but their very high wear resistance and excellent quality of abrasive coating ultimately make them more profitable for regular use.

The high price of professional discs is justified due to their high durability. Products from Distar and Bosch have excellent performance, but the price for one such circle with a transverse size of 230 mm is more than 2,600 rubles.

Classification of professional diamond blades by purpose:

• cutting reinforced concrete;
• making carvings on a concrete base;
• cutting marble, ceramics, granite massifs.

It is very important to understand that if the purpose of professional tools does not correspond to the purposes of use, they will wear out very quickly, and ultimately the costs of performing the work will increase.

Recommendations for selection

The main criterion is the compatibility of the diamond wheel with the working tool and the selected cutting technology. It is important to understand the principle: the diameter and rotation speed of the disks cannot be greater than that allowed for the existing wall chaser or grinder; products for wet cutting are not used in the absence of supplied water; the opposite situation is permitted. Diameters and methods, taking into account the type of construction tool, are given in the table.

The indicated values ​​are average and recommended; to eliminate errors when choosing diamond blades, the following are consistently taken into account:

1. Density and abrasiveness of concrete. Freshly hardened solutions wear out wheels faster and require the use of thicker cutting tools, especially if they contain coarse-grained quartz sand, granite or basalt. When processing reinforced and high-density materials, it is worth choosing diamond discs for reinforced concrete with silver soldering. The minimum recommended thickness of products is 2 mm.

2. Intensity of operation. For one-time work, products with an affordable price and average wear resistance are purchased, for professional ones - designed for a long service life, with high quality and a percentage of diamond chips.

3. Type of working equipment and the presence of a water cooling system. Disks for hand-held power tools have a segmented or turbocharged design and are used mainly for dry cutting; continuous water supply is provided in professional machines.

4. Required cutting depth, this factor is influenced by the diameter of the circle. A large value (above 350 mm) is required when working with volumetric structures and wall blocks, when processing slopes, openings or window lintels - in the range of 150-230, when carrying out internal repairs (grooving for wiring, laying small channels) - 115-120. The upper limit depends on the parameters of the working tool; the diameter of the diamond wheel for a wall chaser (it should be remembered that there are two of them) varies from 110 to 365 mm, for an angle grinder – 230 mm.

5. Dimensions of the mounting hole. When processing concrete, the recommended minimum is 20 mm.

6. Disc quality, manufacturer reliability. Good professional discs for reinforced concrete are offered by Bosch, Keos, Hilti, Distar; acceptable products include products from Zubr, Metabo, Norton, Matrix and many others. Attention is paid to the thickness and method of sputtering the diamond layer; for durable discs, the crumbs are distributed throughout the entire volume of the cutting part.

7. Maximum permissible disk speed. This figure cannot be less than that of a working tool.

All this data must be indicated on the packaging; the markings on the diamond blade itself include information about the main dimensions and material. Grinding bowls are selected according to their intended purpose (rough processing or polishing).

Cost of nozzles

Features of working with the tool

In order to make the most of the working life of an expensive diamond tool, you need to adhere to important rules for its operation:

• cutting reinforced concrete should be done in successive shallow passes;
• the first pass is performed to a depth not exceeding 10 mm;
• the depth of each subsequent cut should not exceed 15 mm.

Before starting work, you need to accurately determine the brand of concrete and its frame, since each material requires different types of diamond cutting tools. If the concrete is reinforced with steel rods and the thickness of the part to be cut exceeds 100 mm, a special disk must be used.

It is also taken into account whether the concrete mass is fresh or old to be cut, because over time the properties of this material change. Old concrete is always stronger than fresh concrete; cutting it requires more expensive tools. The larger the cutting wheel's heavy-duty filler, the slower the cutting needs to be.

Selecting a Diamond Wheel

To choose the right grinding wheel, you need to know about two ways to attach its segments - using silver solder or laser welding. Silver solder discs are used for wet cutting, while laser welding discs are used for dry cutting.

You also need to know exactly what the seat size of the angle grinder is. If the diameter of the mounting flange does not match the inner diameter of the circle, then it will be impossible to use it.

The working rotation frequency of the angle grinder should not exceed the same parameter indicated on the circle. The best option is when the maximum frequency indicated on the circle exceeds the operating frequency of the angle grinder.

Only knowing exactly all the listed dimensions and parameters can you choose the right cutting tool and then successfully complete the job.

Main characteristics

The choice of the type of wheel for an angle grinder depends on the operation being performed and the material on which it will be performed.

Cutting using such attachments can be done dry, wet or combined. The marking indicates this feature, although many varieties are universal tools suitable for processing several types of materials.

The composition of the binder may differ depending on the purpose of the material on which the work is performed.

A disc intended for processing concrete (stone) should not be used to work on metal, as this will lead to increased wear of the working part, deterioration in the cleanliness of the cut and overheating of the working surface.