What is the best angle grinder to cut concrete?
To make the cut even, you can use chalk or a marker to mark a straight line for the trimmer on the concrete, and then fix near the marking wooden bars that will make the cut even. Then you can cut shallow mowing lines on a concrete surface along wood guide bars. The depth of cut should be less than 0.5 to 1 cm. The presence of a shallow little cut will allow you to further perform the required depth of concrete cutting.
If you need to cut the concrete to a depth of more than 100 mm, for example, you need to cut gaps in the concrete wall, you should use the special disc saws for concrete (electronic or hydraulic cutters), which can help you quickly and accurately make the cut of concrete to a depth of 160 mm on one side of the concrete structure. The cross section of the diamond disc should usually be more than 350-400 mm. Concrete saws and diamond blades can be purchased or rented.
To get a positive result and make the efficiency of concrete cutting better, you can follow these tips:
Determine the type of cutting: wet or dry
Concrete is usually cut with water (wet cutting), sufficient water can significantly reduce dust, save and increase the life of the diamond disc and increase cutting efficiency (with wet cutting the process can be continuous). But when there is no water source near the work area, the work is done by dry cutting. As mentioned above, in dry cutting, the process must be intermittent and superficial. If you need to cut to a great depth, you must make several shallow cuts.
What to cut concrete with: methods and equipment
Different methods and equipment are used to cut concrete structures. Let’s list the main.
Diamond cutting of concrete
Diamond cutting. the most common way to cut concrete. Basic principle. Using a cutting tool, the working surface of which is sprayed with diamond. This gives the tool high hardness, which is necessary for effective sawing of concrete and reinforced concrete structures. Various types of hand and machine equipment are used for diamond cutting: angle grinders (angle grinders), also known as “angle grinders”, gasoline cutters, diamond drills, wire saws, floor saws and wall cutting machines. In addition, there are two types of cutting. “dry” and “wet”. “Dry” cutting is done with diamond discs installed in “angle grinders” or gasoline cutters. In this case, the tool overheats quickly and has to be cooled down regularly, which takes up working time. You also get a lot of concrete dust in the work area. Wet cutting uses water to cool tools and capture dust. This keeps dust out of the work area and causes wear and tear on expensive consumables (diamond discs, diamond bits and wire saws) much slower than with “dry” cutting.
Diamond cutting allows you to exclude deviations from the correct dimensions of the opening. The seams on the surface remain accurate and level, and the noise level does not reach critical values, which is also a big plus. No vibration and dynamic loading from the diamond equipment, which can lead to cracks, damage the integrity or destruction of concrete structure. We can say that diamond cutting. the most efficient, productive and fastest method of cutting concrete. Minus is only the high price of consumables.
This method is used to make holes and openings in concrete slabs. The oxygen lance is the operating tool. Thick-walled metal tube preheated to 1400° C. To do this, welding machines or gas torches are used. Then oxygen is injected into the pipe. After feeding oxygen the end of the lance ignites, its temperature reaches 2000° C. The heated end of the tube is pressed against the surface and buried into the material. From the impact of high temperature concrete burns and slag is formed, which falls into the gap between the pipe and the wall of the pierced structure. In order for the red-hot lance to effectively burn through not only the concrete, but also the reinforcement in it, it is also necessary to increase the thermal power of the lance. Several methods are used for this: metal powder is fed into the pipe or steel bars are placed inside the pipe. The powder ignited forms a torch up to 50 mm long and with a temperature of approx. 4000° C. During the burning process the lance is continually shortened. Depending on the thickness of the material to be pierced the length of the burnt part of the lance can be 5-25 times the length of the pierced hole. Speed of piercing holes. up to 10 m per hour. Cutting concrete with the lance method can be done in any spatial position, but it is preferable to do it from the bottom upwards. In this position, the slag from the burnt material falls out of the gap due to gravity and does not block the lance’s travel.
Oxygen-dip method enables drilling of reinforced concrete structures down to a depth of 4 m, it does not cause vibrations or loud noise. But it must be remembered that this method requires strict adherence to safety precautions.
For concrete cutting by waterjet method stationary and portable machines are used. High-pressure water pressure applied to the concrete surface serves as a cutting tool. The water includes abrasives that increase the efficiency of the cutting process: electrocorundum grains, silicon carbide, garnet sand, etc. cutting depths depend on the pressure of the water jet. If necessary, not only concrete can be cut, but also the reinforcement framework of the construction. Advantages of the technology. high precision of cutting and fire safety that makes it possible to work in conditions of high fire risk: in oil and gas industry facilities, tunnels, sewers, wells and hazardous pipelines. The waterjet method allows to cut concrete to a depth of 1 m, to execute openings of any shape and at any angle, and does not create dust, vibration and noise. Therefore, waterjet cutting is used in cases where you need to work delicately: in the vicinity of neighbors or dilapidated structures that can collapse from the strong vibration. This method of cutting concrete is one of the safest and has a wide range of applications. For example, it is also used to create a decor on the concrete surface. Drawing of patterns and other artistic elements on floors and walls.
Concrete poles for power lines today
The basis of any transmission line are posts of reinforced concrete for transmission line supports. This product is manufactured in accordance with TU 34 12.The material used in the production of the poles was 11410-89 which replaced GOST 23613-79. The basic material of the transmission towers is concrete and reinforcement. Concrete class must be B30 with high frost resistance (f200) and water repellent properties (w2 or w4).
Electric poles are made of heavy concrete by vibrating method. To create power transmission line CB 95, CB 105, CB 110, depending on its geometric shape uses special molding and equipment. Pre-assembled reinforcement cage of heat-treated steel reinforcement of class At-IVK and A-IV with a profile diameter of 10 to 32 mm.
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The reinforcement is then stretched and the concrete is poured into the mold. After that, the template is closed with the second part, fixing them to each other. The next step in the production of the CB pylons is shrinkage of the concrete by means of vibration.
After a few minutes, when the remaining air bubbles leave the future electric pole, the reinforced concrete support is sent to the steaming chamber, where a constant temperature is maintained, for the mixture to harden.
Below see. the table with the sizes and characteristics of reinforced concrete pylons CB.
Concrete pole CB 105
|Support mark||length||width||mounting width||height||installation height||weight|
|CB-95||9500 mm.||165 mm.||150 mm.||240 mm.||165 mm.||750 kg.|
|CB-105||10500 mm.||200 mm.||180 mm.||280 mm.||190 mm.||1175 kg.|
|CB-110||11000 mm.||185 mm.||175 mm.||280 mm.||165 mm.||1150 kg.|
Wall saw with their own hands
Makeshift cover made of plywood for angle grinder for wall sawing
To punch through the walls for wiring with your own hands, you can make a homemade punch cutter. To make it, you will need:
- Powerful angle grinder from 1.2 kW. This figure is extremely necessary, because the tool will rotate two diamond discs.
- Pipe with an inner section of 50 mm (metal).
- Sheet iron with a thickness of 2 mm or more.
- Number of castors or bearings 3-4 pieces with a diameter of 2-3 cm.
- Metal spacers for their arrangement between the two disks (it is better to order them in advance from a turner).
- Metal fasteners (nuts, screws).
- Two or three pieces of pipe with a small cross-section.
In addition you need to prepare a file, a vice, a welder, a hammer, a caliper, a ruler, a pencil. The finishing touch. coating discs with nitro enamel. That’s why it is necessary to prepare it as well.
The principle of constructing a home-made miter cutter is to attach two discs to an angle grinder to cut through the concrete. Between them with the help of spacers maintain the required distance (the width of the future hole).
Drill cutter from a drill
Make with your own hands the right tool from a drill is easy. It is only necessary to fix in the chuck of the drill the desired cutter. But the formation of grooves with such a device is not quite qualitative. The grooves have different depth and width.
Varieties of tools for cutting concrete
In the construction process, there is often a need to drill holes in a concrete wall to change or create openings for doors, windows or communications. For this purpose, concrete cutting is performed using a variety of equipment, ranging from hand tools, to heavy professional machines.
However, it is worth considering that drilling into walls is associated with a huge amount of dust and noise. Therefore, before we begin the work, consider methods of cutting monolithic surfaces.
Concrete cutting techniques
To cut concrete, it is made by chiseling, drilling, crushing and grinding. There are two methods according to the way the work is done:
- Dry. In this case the work is carried out with breaks that are necessary for the equipment to cool down. In addition, when dry cutting concrete walls, you will have to use a special vacuum cleaner or wait until the dust settles (because of the volume of dust, you, elementary, will not see the place of cutting). Another disadvantage of this method is the small depth to which the cutting tool can be immersed. Because of the strong side friction, the disc will become very hot and fail more quickly.
- Wet. This is considered the most appropriate and least time-consuming way to cut dust, because you do not have to wait for the equipment to cool down. Water, fed to the cutting wheel, performs several functions at once: it cools the cutting tool and “nails” the dust.
To make a quality and fast cutting of concrete without dust, it is recommended to use the wet processing method. Various diamond-powdered tools are used for this type of work.
Today, cutting openings in concrete is carried out with the following units:
Such equipment for cutting concrete is most commonly referred to as an “angle grinder”, but in the professional sphere this machine is called an angle grinder (angle grinder). Such a handheld cutter allows you to cut holes in the wall up to 13 cm thick. Tools of this type can have different power, and they are also equipped with special attachments, which are fixed on the angle grinder with a screw thread. Cutting is most often done with grinding, deburring, and cutting diamond discs.
Useful at! When choosing diamond cutting discs it is recommended to buy products with notches for usual concrete and without notches if you plan to cut reinforced concrete constructions, because the projecting elements of the disc will catch on the armature.
Handheld cutters have high maneuverability, so the work is performed in large volumes. Angle grinders and diamond discs on concrete, on the other hand, are only suitable for small areas. If you use such equipment for large construction projects, you or your workers will quickly get tired.
The wall saw is another tool for cutting concrete with a diamond blade. The unit consists of a motor, hydraulic pumping station, guide rails (for vertical and horizontal fixation), cutting disc (diameter over 25 cm) and control panel.
Machines of this type offer a higher quality of cut. In addition, the unit has the following advantages:
- Cutting depths up to 7.5 cm are possible.
- Suitable for more complex and extensive work.
- Cutting reinforced concrete is as fast as possible with the machine.
- Low noise and vibration level.
- Reliable fixation on the work surface.
- High cost of a machine for cutting concrete.
- Training is required to use the machine.
- Requires a 380-watt power supply.
Floor saws (floor saws)
For cutting horizontal concrete floor slabs, creating expansion joints and openings, joint cutters are often used. A floor saw consists of a metal frame on wheels, a motor and a cutting wheel. With the help of this equipment, a hole with a depth of up to 2.7 cm can be cut.
- Stationary. Machines of this type are used for thick layers of monolith.
- Portable. These units allow you to make cuts of varying depths and configurations.
Its advantages include the ability to cut thick surfaces with minimum vibration. The disadvantages are high cost and the possibility of processing only horizontal surfaces.
Wire rope machines (cutters)
Wire rope machines are available with both hydraulic and electric drives. Also this machine type is equipped with an oil station, rope stands, rollers and a cooling system.
Rope cutting concrete is used for the dismantling of large buildings (bridges, piers, columns and much more). Such specialized cutter can make holes up to 50 cm deep. Cuts can be made in any direction.
The main cutting element in such machines is a special diamond-coated rope.
This type of equipment is considered expensive and difficult to work with, so rope machines are used for various works (dismantling, cutting reinforced concrete, blocks and pipes) on large construction sites.
However, making cuts with angle grinders or wall saws is not always possible due to lack of electricity. In this case a chain saw for concrete is used, or as it is also called a gasoline cutter.
Saws for concrete cutting
A gasoline or compressed air powered concrete chainsaw is often used for manually cutting concrete. This lightweight and accessible tool does not require any special skills, so it is optimally suited for construction work performed with your own hands.
How to cut concrete properly?
The basic rule for choosing discs for cutting concrete with angle grinder. the denser the concrete, the finer the diamond fraction. When sawing reinforced concrete by hand, it is necessary to use discs without holes. they can cling to the frame reinforcement and injure the master.
A diamond wheel can cut much more brick than a regular abrasive wheel. If you only need to break a few bricks into two pieces, then, to do. you can do it with a construction pickaxe. However, in this case, only one part remains intact.
Is there a technology of cutting concrete without noise and dust?
When thinking about what to cut the concrete with, you must also take care of reducing the amount of dust, which inevitably appears during the process of work. In some cases it is not possible to do anything and you have to work in difficult conditions, but in other cases it is possible to remove the dust. The main thing is not to violate safety requirements and to use proven methods.
Concrete cutting is a deliberate mechanical action on the monolith with rotating parts of the tool. Cutting is not accompanied by impact noise, but always involves noise from the electric motor of the tool drive and the work of its moving parts that cut a groove in the stone or cut rebar, cut into pieces, etc.д.
Different methods are used for cutting concrete. manual, machine, wet and dry. The first two are conditioned by the type of tool chosen, the wet method involves the impact of water on the cutting part and on the concrete surface itself, the dry method does not use the water supply. Regardless of the selected cutting method, the amount of dust that accompanies the process is always quite high.
The most common methods of cutting concrete:
- Diamond cutting of partitions and walls with hand tools (angle grinder and others).
- Diamond cutting with a stationary type wall saw.
- Diamond cutting with a wire cutter.
- Using it to cut the rope.
When using a hand-held tool (most often an angle grinder), you can connect it to a construction vacuum cleaner, which will suck up almost all the dust that appears during the cutting process. If it is not possible to connect the tool to a vacuum cleaner, everything can be done with your own hands.
What you will need to make an adapter for a construction vacuum cleaner:
- Drainage branch made of polypropylene, 50 millimeters in diameter, 45 degrees.
- Reinforced tape (it is more reliable).
- High quality masking tape.
The process of creating a vacuum cleaner nozzle for dust extraction:
- Set the angle grinder as steadily as possible on the table or floor so that it lies upside down with the disc parallel to the plane of the base.
- Take the outlet with pliers or a clamping tool, turn on the angle grinder and “saw” the outlet along the body, 3 cm under the tool cover.
- To screw the outlet to the case of angle grinder with reinforced adhesive tape very tightly, in a tense manner, going a little bit into a saw disk (a few centimeters). The fixing of the spigot must be secure, so that it is attached firmly.
- Painting tape to tape the open side of the housing, thus connecting it to the branch. Then it is possible to connect a construction vacuum cleaner and remove dust during work.
This system does not require any changes to the tool, but before using it, it is advisable to consult with the manufacturer’s representative on the possibility of making modifications.
Cutting concrete with a hand tool
Due to the strength of the material, not all hand tools are suitable for working with it. Most often for these purposes use an angle grinder (aka UGS, angle grinder). A special nozzle is used for cutting concrete in the form of a diamond wheel, which can be solid, segmental, combined.
Types of diamond wheels for angle grinder with which you can cut concrete:
- Continuous. made with a continuous diamond cutting edge, so that no chips appear in the work. The nozzle heats up periodically and therefore requires constant cooling with a jet of water.
- Segmented blade. solid base, segmented edge. The disc is inexpensive, but it wears out quickly on tough materials. Suitable only for dry cutting.
- Combination (aka turbo-diamond) disc is considered a universal disc, can withstand maximum loads, even reinforced concrete can be cut with it.
Nozzles are chosen according to the material to be sawn, as well as taking into account the type of work, conditions. Concrete with indentations of more than 10 centimeters can only be cut with discs of increased strength (turbine). All disc segments are fastened to the blade by laser welding or silver soldering. The former can only be used for dry cutting, the latter for wet cutting.
The circle must be made with an inner diameter corresponding to the diameter of the angle grinder. Also important is the frequency of rotation of the disc. it is desirable that it be higher than the indicator of the angle grinder. Depending on the selected type of cutting and proper selection of the tool, the volume of dust produced during the work can be different.
So, if you long saw concrete with insufficiently strong and ineffective tools with nozzles, there will be a lot of dust, but the result is minimal. You can reduce the amount of dust by using the wet cutting method. water keeps the tool from overheating and prevents dust. So you can speed up work and increase the life of diamond nozzle.
the water supply can be organized in different ways. from spraying concrete with a sprayer periodically during the work to fixing a hose to the tool so that the liquid flows in a continuous stream on the disk.
A convenient nozzle is made from an ordinary plastic canister. You also need a torch, a container of the right size, with a nozzle that matches the diameter of the hose of the vacuum cleaner.
Next, on both sides of the need to make planting holes for easy changing the direction of rotation of the disc. A slot of suitable size is made under the wheel, and another hole is cut for mounting the cutter. Carefully connect the hose to the neck of the canister, then secure with an adapter ring with a clamp. place the angle grinder into the hood, all components are securely connected. Cover the unused hole with a cover.
How to cut concrete properly?
Concrete is usually cut with diamond discs. There are different solutions for cutting concrete under certain circumstances.
In this case, you can use an angle grinder (angle grinder or “angle grinder” in common parlance) and a 105-125 mm sintered diamond disc, such as a segmented diamond disc, turbo diamond disc or turbo diamond disc with a wave silent housing, mounted on an angle grinder. Segmented diamond cutting discs may cause more problems when cutting, due to their segmented edges, but they cost significantly less than other types of discs. Turbo. wave-shaped diamond discs can be used for heavy-duty applications such as: cutting concrete and reinforced concrete, but their price is the highest.
You can first cut through the concrete to a depth of 1 cm and see how the angle grinder and diamond wheel behave. If the angle grinder has no problems in operation, and the disc cuts and does not “stand” in place, you can continue cutting concrete and rebar to achieve the depth of cut you want. Each subsequent cut should not be deeper than 1.5 cm.
To reduce dust generation, you can have someone spray water on the diamond disc and the cut while you are cutting. This is also necessary to cool the diamond blade and increase blade life. If the use of water is not safe for the power source of your angle grinder, you should cut the concrete “dry”. When dry cutting concrete, air is used as the heat transfer medium (cooling), so after a certain period of time you must remove the diamond wheel from the cutting area and allow it to rotate freely to cool the segments. The period can be from a few minutes to a few seconds, depending on the hardness of the concrete being cut (the harder the concrete, the shorter the cutting period should be).
Throughout the entire cutting process, you must use a professional dust respirator, otherwise you can cause serious damage to your health.
In addition to an angle grinder you can also use professional diamond saws. With a circular diamond saw, you can also use a larger-diameter diamond saw blade, thereby improving cutting performance.
Concrete dust is extremely harmful to humans, so it is necessary to wear a respirator while working with the angle grinder. You need it for both dry cutting and wet cutting. In both cases, the tiny fragments of grout are spread around the room and into the lungs. This in turn leads to diseases such as cancer or silicosis.
In addition, “canned” safety glasses are used to protect the eyes, and special headphones help protect against the noise made by the power tool.
And finally, don’t forget gloves. an angle grinder is a very dangerous device. Loss of alertness, even for a moment, can result in very serious injury.