Concrete is a mix of sand, gravel, cement and water, and it is everywhere. You may want to cut some blocks for your yard, cut a wall or slab or whatever you want, but if you are trying to cut it, you have to do it in the right way because it’s actually a hard job to do, and instead of hiring a contractor to do the job and it may cost you a lot of money, you can do it all by yourself if you have the right tools.
To make it easy you have to follow some steps, procedures and use the right tools like the proper blade type, the power of the circular saw…etc.
It also depends on the type of concrete that you want to cut whether it is a hollow core block or reinforced concrete blocks. In fact, there are specific saws that are designed for concrete cutting which are called “concrete saws” but they’re a little bit pricey, but circular saw are efficient and can do it flawlessly.
Main Elements of Concrete Cutting
- Types of blade for concrete cutting
- Type of circular saw
- How you can cut concrete with the circular saw
circular saw blade for cutting concrete
There are several types of blades; each has its own use. Actually, the most important thing about cutting concrete is the blade, as we learned before in this guide that the blade is what really makes the cut, not the saw, meaning that if you have the best concrete saw in the world but have the wrong blade, you won’t cut anything and you will end up breaking the blade.
The blade can be made from many materials, but in our case, we will focus on three types designed specifically for our job:
- Diamond Blades
- Masonry Abrasive Blades
- Wet/Dry Cutting Blades
They are all can be used in cutting concrete, but each one has its own advantages and disadvantages. For example:
A masonry abrasive cutting blade is inexpensive, so they are affordable but the bad side is that the cutting speed is not good, you will take a longer time to cut your concrete block as well as they wear so quickly, and you have to replace it from time to time if you have a lot of jobs to do with it.
The diamond blades are even better than the masonry abrasive ones. Here, we are dealing with the strongest material on earth, the diamond. Sure, the blade is not made out of diamond, but only the teeth are made out of a compound of diamond and another reinforcing metal, it’s a composite material. Diamond blades are more expensive; they do not wear easily and stay for a longer time, and if you are a contractor who always deals with concrete cutting jobs, diamond blades will be the prefect tool for you.
The wet/dry cutting blades are actually diamond blades but the problem is that cutting concrete makes the blade extremely hot, and here comes these blades
Wet circular blade
The wet cutting blades are on the top, but you must add a low stream of water during the cut, this will lubricate the blade during the cutting process and also it will prevent the silica dust from being produced.
Dry circular blade
the dry cutting blades are specially designed so they expel the heat quickly by making segmented teeth on the blade. The best thing about this type is that it has a long life span but be careful, they produce high amounts of silica dust during the cut. Therefore, I advise you to wear a respirator or dust mask.
This video shows you exactly what it looks like to use wet cutting blades:
If you are doing a quick job, then aim for the masonry abrasive blade.
If you are a contractor and doing many concrete cutting jobs, aim for the diamond blades.
Only buy the wet cutting blades if you have a specific concrete saw or a circular saw with special parts to add water stream to the cut during the process.
Contrary to the dry blades, wet blades always must have water added to it during the cutting process.
Type of circular saw is used for cutting concrete?
The type of circular saw doesn’t have a significant effect, but I prefer using the DEWALT DWC860W because it has a built-in water feeding system that will help you reduce the dust and prevent the overheating, and I’ve already tried it with the DEWALT DW4701 blade for cutting retaining wall blocks. If you want to buy any other type, just make sure that the RPM is above 3000 just to increase the cutting speed.
How to cut concrete blocks with circular saw?
- To be able to cut concrete with circular saw, the thickness must not exceed 15 cm max or things may become difficult.
- Before we get started, you should follow these tips:
- Wear all your protective gear.
- Make sure the surface that you want to cut is clean.
- Make sure you have the right blade and that the blade is not dull to avoid kickback.
- Circular saw with the proper blade
- Hearing protection
- Safety glasses
- Respirator or Dust mask
- Chalk line
- A Sledgehammer
Step 1: Mark off the cutting path with the chalk line
Step 2: Adjust your circular saw to be aligned with the chalk line and have a cutting depth of 50mm and let it start to reach max speed.
Step 3: Start the cutting slowly and don’t force the blade or the circular saw, just let the machine do the cutting by itself and you do the feeding slowly.
Step 4: If you are cutting with wet blade, then make sure you have someone helping you add a slow stream of water to the blade during the process to overcome the heating and prevent the dust.
Step 5: Do not make a continues cut, stop the blade every 45 seconds and do it again.
- If you want to cut in reinforced concrete, do not do it by yourself because of two reasons:
- You will encounter rebar and things may not be good with you, you will need a professional.
- Reinforced concrete is a structural element in your building, so be careful when dealing with it, because cutting the rebar inside the RC may cause cracks in other parts of the RC.
- If you have a thickness larger than 15 cm try to cut the block from both sides and use the sledgehammer to make the block split.