If you have a big concrete surface that needs to be worked on, such as if you need to remove the top layer of resin, if you need to add a new coating overtop, you need to even out bumps, or anything else of the sort, then two options you have at your disposal are to use a concrete grinder or a concrete scarifier.
Now, these two tools are similar in the sense that they are used to remove concrete from a surface, but they are actually fairly different tools, especially in terms of their functions and what they excel at.
Let’s figure out what both concrete scarifiers and grinders are, as well as which one is the better choice for you.
Concrete Scarifiers and Grinders: The Basics
Before we get into talking about the differences between these two tools as well as which one is ideal for you, it’s probably a good idea to figure out what they both actually are, so let’s do that first.
What Is a Concrete Scarifier?
Concrete scarifiers are also known as surface planers, and these are very large tools or milling machines that cut or scar the surface of concrete with a set of large cutters that are fixed onto a rotating drum. The cutting wheels, also known as flails, are mounted onto the shaft of a circular drum which can be removed from the machine.
Exactly how many cutting shafts the drum in question has depends on the exact machine model. These cutters or flails can be made out of a variety of materials, such as hardened steel or tungsten carbide. They also come in a variety of different weights, diameters, and with a different number of cutting teeth (depending on what the exact purpose is).
This drum and the teeth spin in a very fast circle, thus pummeling the concrete underneath and removing big chips of it at a time, leaving behind a very rough surface. Some of the most common applications of concrete scarifiers include leveling misaligned concrete joints, evening out uneven surfaces, cutting grooves in walkways and sidewalks to make them slip-resistant, for heavy milling, and for removing coatings.
What Is Concrete Grinder?
A concrete grinder, on the other hand, is more like a basic grinding or sanding machine that you might be used to. These are large machines that feature horizontal rotating discs that spin in very fast circles. There are also much smaller handheld options available for those times when you need to work in tight spaces.
Keep in mind that there are also a variety of power sources that these machines can use, including electricity, propane, and gasoline. Concrete grinders are designed to just grind away a very small layer off the top of the surface of the concrete, or even just to polish it. The point here is to polish or grind away the concrete without actually scraping or eroding it, thus producing a smooth finish.
What is important to note here is that concrete grinders are designed more for precision work. Some of the most common applications of concrete grinders include getting rid of surface imperfections, getting rid of small bumps, removing oil and grease deposits (as well as other contaminants), and simple polishing too.
Concrete Scarifier vs. Grinder: How Do They Differ?
Now that we know what both concrete grinders and scarifiers are, let’s take a look at the main differences between them, so you can figure out which one is best for you. We aren’t going to cover any similarities, because besides being big machines that work on concrete, there really aren’t any.
#1: Vertical vs. Horizontal Motion
One of the primary differences between these two machines is that a concrete scarifier pounds the concrete vertically from top to bottom, whereas a concrete grinder uses a horizontal grinding motion to polish or grind away concrete from the top layer.
One of these tools really digs into the concrete, whereas the other is a lot finer and just works over the top of it. As you can tell, a concrete scarifier is a much rougher tool, whereas a concrete grinder is a bit finer and more precise.
#2: Grinding Discs vs. Teeth
Related to the above point, as you probably know by now, a concrete scarifier uses fairly large teeth to really hammer down into the concrete and chip away at it, whereas a concrete grinder uses much smoother grinding discs. You could almost say that the concrete scarifier is like a much heavier-duty version of the concrete grinder.
#3: Handheld Models
Another huge difference between these two machines is that concrete grinders can actually come in handheld models, much like a normal grinder that you would use for any other project. Yes, concrete grinders can also come in walk-behind models which look more or less like floor buffers.
On the other hand, concrete scarifiers mostly come in walk-behind models, as the way in which they function requires them to be very large.
Although we really aren’t going to go into an exact cost analysis here because the exact cost of each machine does depend on the model in question, the reality here is that concrete scarifiers do tend to be a bit more expensive than concrete grinders.
#5: A Little vs. A Lot
One of the main differences between these two machines is the fact that concrete scarifiers remove a whole lot of concrete from the top and can travel fairly deep down under the surface, whereas concrete grinders are much finer and only remove up to 1/8 of an inch at a time. One is designed for heavy-duty concrete removal, whereas the other is designed to just grind a little bit off the top.
#6: Intended Purpose
Of course, the main difference here is what these two tools are actually intended for. Some of the most common applications of concrete scarifiers include leveling misaligned concrete joints, evening out uneven surfaces, cutting grooves in walkways and sidewalks to make them slip-resistant, for heavy milling, and for removing coatings.
On the other hand, concrete grinders are used for getting rid of surface imperfections, getting rid of small bumps, removing oil and grease deposits (as well as other contaminants), and for simple polishing too.
Which of the Two Should You Use?
Which of these two tools you use really just depends on what your intended purpose is. Take a look at our point above about the intended purpose of each machine. As soon as you figure out what your purpose is, you can then choose the right machine for the job.
The bottom line here is that if you are doing some heavy-duty work, then it’s probably the scarifier that you need, and if you are doing light work, then the concrete grinder will likely suffice.