What kind of disc to cut concrete with an angle grinder. Diamond cutting disc – cut stone like a charm.

What to saw a concrete slab with rebar

It happens that reinforced concrete structures need to be cut:

  • To create and expand window and door openings;
  • To change the layout, dismantling;
  • For installing outlets and built-in switches;
  • For laying wires and cables;
  • In construction when repairing bridges, overpasses and other complex structures.

How and what to cut reinforced concrete? Today there are different techniques and tools for cutting solid stone with an integrated metal frame, which we will discuss below.

Description and classification

A diamond disc is a thin metal disc with diamond cutting tips that are permanently mounted on its cutting edges. They are made from industrial ground diamonds, which are pressed into the metal binder. hard alloy, steel or titanium. Plates are attached to discs by silver soldering or laser welding. Modern technology connects cutting tools with metal substrates using powder brazing. So they last longer. Once the cutting part of a diamond disc has been sharpened, it is completely ready for use.

In order to cut reinforced concrete or concrete, a variety of equipment is used, such as: stationary machines, floor saw, gasoline cutter, angle grinder. To them attach circles of various grades. Their distinctive features are:

  • The configuration of the working edge.
  • Composition of the binder.
  • Number of diamonds per surface area.
  • The qualitative indicators of diamonds.

In order to choose the one that best suits your needs, you must read the classification.

There are several groups of circles. The most important factors are: the function and shape of the cutting part.

Diamond cutting discs

This group is subdivided into three subgroups. These include:

How to use an angle grinder to cut and smooth concrete

  • Segmental for dry-cutting. Concrete is cut dry with a hand tool. For this purpose, an angle grinder (angle grinder) and a chisel cutter are used. On the base of a segmented wheel, the diamond outline is arranged in individual sectors with radial through grooves between them. In the process of cutting, the plates are under great strain, and the discs are heated. Slots are required for stress relief, waste removal, heat dissipation, and compensation for linear expansion. This group includes diamond tools for cutting fresh concrete. The difference between these circles is that they cut the material immediately after hardening. The diamond layer is usually filled directly on the body without using a bonding agent.
  • Endless (solid). There are no segments on such circles. And in order to distribute the tension, there are holes. they are used when water-cooled cutting is performed. Wet processing is carried out on stationary equipment. This equipment has the constructive ability to supply coolant.
  • Diamond discs for reinforced concrete. These discs have a segmented design, but the teeth contain more diamonds than a conventional disc type. They are slightly thicker. We must take into account the fact that reinforced concrete at home is very difficult to cut. angle grinder heats up quickly, it penetrates the dust (to prevent dust penetration requires protection from dust bearings and dustproof motor). With a hand-held power tool, you can cut reinforced concrete no deeper than 10 centimeters at a time. After that, the equipment will shut down to cool the disc and motor.
  • Turbo segment diamond cutting discs. They are in one piece and are cooled by a wave-shaped surface. expensive than conventional wheels, but they make up for it with better functionality and longer service life. Even reinforced concrete can be cut with them, if the diameter of reinforcement will not exceed 10 centimeters.

Diamond grinding discs

Use these wheels to grind concrete, if you need to level the floor before applying a decorative coating. This process is done with a special grinder or angle grinder. They are distinguished by the fact that the diamond cutting layer is applied on a tapered circular surface that protrudes along the edge. The diamond disc for machining the floor is the main circle, on which several grinding cups are attached, between which there are grooves for dust extraction.

Grinding Concrete with a 4.5 inch Diamond Wheel Blade. How to Grind some Concrete!

Suitable tools

Depending on your goals and capabilities, you can use both specialized asphalt and concrete cutting machines and general purpose tools.

Specialized wheels include:

  • Power-driven cutters. Invented for salvage work, they quickly gained popularity with builders for dismantling structures and laying utilities.
  • Joint cutting machines. Used for cutting channels in walls of various materials.
  • Wall grinders. Devices for cutting any wall to varying depths.

General-purpose tools include:

  • Angle grinders (angle grinders, or “angle grinders”). The most common tool for diamond cutting in private construction. Allow you to cut through asphalt at shallow depths.

When selecting diamond blades, make sure they are suitable for your type of tool. Read the specifications of the replacement discs: the maximum diameter and the size of the seating hole are stated there.

When working with any diamond tool it is important not to overheat it. It can make the disc brittle or destroy the bonding agent in the diamond coating. That’s why cutting asphalt should be done in several steps: after every 0,5-1 minutes of work remove the tool from the material thickness and let it cool down. If this condition is observed, the disc will not fail prematurely. The most durable discs are European brands; the cheapest, but least quality. Chinese. Russian ones are in the “golden mean. And the choice depends on how long and often you plan to use the tool.

Types of discs, their features

The industry produces several varieties of diamond wheels, which can be installed on an angle machine:

Diamond wheels of these types can withstand a very high technological load designed to cut reinforced concrete, but the cost of such nozzles is the highest. They are divided into professional and household, which is common to most construction tools. For different working conditions, they are manufactured by industry in different versions.

Professional discs

Professional diamond wheels with diameters from 125 to 350 millimeters are used for production purposes. Their cost is much higher than that of similar household cutting tools, but the very high wear resistance, excellent quality of the abrasive coating ultimately makes them more profitable with regular use.


Classification of professional diamond discs by purpose:

It is very important to understand that the inappropriateness of the purpose of professional tools is very fast wear and tear, eventually increasing the cost of doing the work.

angle grinder to work with concrete

Concrete castings are very strong in structure, so a tool to work with them is a must. Separately for such works do not produce an angle grinder, but you can be guided by the parameters.

Suitable tool characteristics for working with concrete:

  • Power. not less than 1500 watts. Angle grinder with low power will quickly burn out from the load. In addition, cast constructions are rarely cut with small discs and larger discs need good power.

Special features of the discs application

The basic rule is simple: segmented diamond disc for concrete should not be used for harder materials, especially metal, the exception is made only for the nozzles, designed for concrete. Choose the type and diameter of cutting tools still need to be at the preparatory stage, they depend on the nature of action, density and thickness of the structure. To avoid errors, it is recommended to pre-mark the surface, and with high demands on the accuracy of the cut. fix a wooden bar along the line (it will prevent the departure of the circle to the side). Then with an angle grinder or a chisel gun a guide cut not deeper than 2 cm is made. The way in which the next steps are carried out is influenced by the cutting method: dry or wet.

The first method is recommended when there is no tool with a water cooling system, when working near electrical installations, when there is a risk of dampening other building materials (for example, decorating or insulating) or other restrictions. Dry cutting with diamond discs requires thorough preparation of the surface, in particular, cleaning it from dirt or foreign substances. A great deal of dust is generated in the sawing process, so the use of personal protective equipment is imperative.

Regardless of the tool (angle grinder, floor saw or hand torch) continuous work time does not exceed 120 seconds (better 30), renewal is possible only after a sufficient drop in temperature. Due to the special arrangement of the segments, dry cutting discs are designed to channel concrete particles and allow natural cooling, stopping not only to cool them down, but also to allow dust to settle and the motor to “breathe”. As a consequence, the maximum cutting depth is limited to 25 mm at a time, a disc with a diameter of 230 mm is more than enough. An exception is made for dry cutting channels in concrete for pipes, to accelerate such work it is advised to choose a thick diamond disc from 350 mm.

Reinforced concrete requires special attention. Wheels with wide segments are well suited for a quick sawing of medium-density concrete, but may stall on the iron, increasing the risk of knocking the angle grinder out of his hands. There are two ways around this problem: the use of specialized discs for cutting reinforced concrete or a change of nozzles in the process (the reinforcement is cut thinner and more solid). When processing high-density concrete with a hard coarse aggregate and a frequent arrangement of bars, it is advisable to choose the first option, in the same case it is desirable to apply the wet cutting method.

Technology with a constant flow of water is less demanding to prepare the surface, this cooling facilitates penetration of discs for angle grinder on concrete or reinforced concrete deep into the surface, which allows you to work quickly and without interruptions. Continuous water flow and tool condition are monitored during the process. Sparks are a sign of overheating and if they occur, you should cool down the torch or increase the cooling intensity. in any case, the wet cutting method is considered the most effective and safe for health, it is resorted to when processing large amounts of concrete.

Variety of diamond blades

Cutting concrete can be dry or wet, and this is closely related to the choice of blade type. Dry cutting is less labor-intensive, but needs stronger and therefore more expensive disks. Wet cutting (using water to wet the cut) usually requires extra hands and will take longer to complete.

When choosing a cutting method, decide what’s more important to you: saving time and labor. or saving money on buying blades? Once you have your priorities straight, you can buy. You have to choose one of the three types of blades: segmented, solid or turbo.

In the segmented disc, the working surface is divided into sectors that allow air to cool it better. That’s why they overheat less and can be used “dry”. The disadvantage of such disks is less smooth cutting and difficulty in controlling the tool. But when sawing concrete high precision and accuracy is rarely needed, so these discs are recognized as the best in this category for value for money.

In the solid disc, the cutting edge is not segmented. It allows you to get a smooth and neat cut. But you can only use these tools for wet cutting because they overheat too much.

The turbo-disc combines the advantages of the previous two types: it perfectly copes with dry concrete and cuts it accurately. Its external appearance is like a ribbed plate; this undulating structure allows air to circulate, and a solid cutting edge is maintained. But it has a disadvantage in that it is more expensive.

Note: Whichever type of blade you choose, you should not cut through concrete for longer than two minutes! From time to time you need to remove the tool from the thickness of the material and let it work “idle” so that the air cools the cutting edge.

How to make your own hands guard under the vacuum cleaner

An angle grinder with an integrated vacuum cleaner can help you get rid of the small particles of material that form while cutting with an angle grinder. But what to do if you need to saw concrete with an ordinary tool without additional options? The easiest solution would be to buy a cover for the vacuum cleaner separately or make a device with your own hands. You can involve a helper, who will collect the particles formed during cutting with a vacuum cleaner.

It is easy to make a convenient nozzle from a simple plastic canister, which is often sold as auto “antifreeze”. For work you will need a construction cutter and a container of suitable size, the nozzle which fits the diameter of the hose vacuum cleaner.

The sequence of making is as follows:

  • Seating holes are cut on both sides so that the direction of rotation of the disc is reversed easily.
  • A cut of a suitable size is made under the circle.
  • To attach the cutter of the “angle grinder” another hole is cut.
  • Hose is coupled to the neck of the canister and secured with an adapter ring with a clamp.
  • “Insert the angle grinder into the cover and connect all components.
  • Cover the opening that is not in use with the lid.
disc, concrete, angle, grinder

A simple five-liter polyethylene bottle also makes a good dust collector. It is fastened with a standard protective cover, and the pipe of the vacuum cleaner to the throat. Such a design is suitable for any type of work, except for grinding.

One last tip: In order to make the cut evenly, first make a notch. Then wooden blocks are fastened along the line. After that, a shallow cut of up to 1 cm is made, the stops are removed and the work continues. Throughout the entire process the blade of the disc is sprayed with coolant. All manipulations must be performed in protective goggles, respirator and gloves.