If your cut doesn't need to be exact, use a cold chisel and hand sledge to cut the concrete. Score the length of the cut three or four times with the chisel. A circular saw with a masonry blade can also be used to either score or completely cut through the block.
Use your dominant hand to grip the back handle and push the blade forward and backward. Begin cutting at the edge of the concrete and slowly follow the chalk line. Don't press the blade into the ground—let the weight of the blade and saw do the work. Remove the blade every 30 to 45 seconds to avoid overheating.
Step 1. Choose the type of blade you prefer to work with for the job: dry-cutting diamond or wet-cutting diamond. The former works with a circular saw or handheld cut-off saw, although you will want to wet the concrete to minimize the dust that flies while you cut.
Late sawing can result in random concrete cracks. Shallow cracks aren't sufficient to prevent uncontrolled cracking while deep cuts are excessively labor intensive and undermine the aggregate interlock in the concrete.
Timing is very important. Joints should be sawed as soon as the concrete will withstand the energy of sawing without raveling or dislodging aggregate particles. For most concrete mixtures, this means sawing should be completed within the first six to 18 hours and never delayed more than 24 hours.
While experience will help you get a better idea of what works for your concrete and climate, there is a rule of thumb to start with. Cuts should be approx. 2-3 times the thickness of your slab in feet. For example, a 6” slab would have cuts 12' – 18' apart.
A concrete chain saw contains diamond grit to give it the strength and durability required to cut tough surfaces. Concrete chain sawing is ideal for small openings or on odd shaped materials. This technique works on brick, block and concrete up to 25 inches thick.
Diamond Grit TORCH Sawzall Reciprocating Saw Blade (48-00-1450) is intended for cutting brick, block, concrete and stone.
Although the various concrete cutting saw is available, an angle grinder is the most convenient tool for small concrete cutting work.
Wet concrete is very difficult to cut, and fully cured concrete can fracture as it's being cut. So if possible, cut concrete when it's hard but only half cured. The cut will come out smoother with less dust.
A cold chisel is the right hand tool for breaking up small areas of concrete. Demolishing concrete is a heavy-duty task that calls for heavy-duty tools. Most concrete demolition projects call for the use of a jack hammer or hammer drill.
Hard Materials Cutting Wheels
Dremel 545 and EZ545 are both diamond wheels great for cutting, sawing and carving hard materials; such as, marble, concrete, brick, porcelain, ceramics, hard epoxy and soft and hard wood. Do not use them on metals.
Cut Through Concrete with Oscillating Tool Accessories
By adding a carbide grit oscillating tool blade, you can use your oscillating multi-tool to cut and shape concrete. You can also use the device for jobs like grout removal.
The carbide hacksaw blades cut ceramics, steel, aluminum, plastics, concrete, brick and wood cleanly and quickly in all directions.
Because of their exceptional hardness, diamond coated reciprocal saw blades create smooth cuts through hard materials, such as concrete and stone.
One is its quality. According to experts, a low-quality diamond blade can only last around 12 hours of non-stop cutting, while high-quality blades can cut materials up to 120 hours. Another thing that can affect the blade's life is the material you are cutting.
Use a standard circular saw, equipped with a corundum or diamond blade, for small tasks. For slabs, it's best to cut through the top inch, then use a sledgehammer to break off the rest. The jagged edge left below the cutting line provides a good rough edge for the new concrete to bond to.
With a 14-inch circular blade on a cutoff saw, the maximum depth is about 5 inches.
Ring saws are cutting tools which are typically used to cut into concrete or for making cuts into brick walls for windows or doors, for example. They are particularly useful for confined spaces and for areas that are hard to reach.
Push the bull float in one direction only across the concrete, keeping its front edge slightly above the surface by raising or lowering the handle. Two or three times is enough. Don't overwork the concrete or you'll weaken it by drawing too much sand and cement to the surface.
Rule #1 – Keep joints as square as possible. Rule #2 – In order to prevent intermediate cracking, space joints (in feet) no more than 2 – 3 times the slab thickness (in inches).
Concrete lines are also called control joints or cuts. When contractors pour concrete, they include these lines in specific places to control and prevent cracks. As the concrete dries, shrinks, moves and bears weight, it can crack.