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How to Grind Concrete with Angle Grinder

By: David S. Miles | Last Updated: January 17, 2024

Why is it essential to grind concrete floors? Well, if you’ve got a superficial contaminant on the top of concrete-like thin-set, paint, or any unwanted rough texture, you need to remove that before you can put down your new flooring.

So, I will teach you how to grind concrete with an angle grinder and a brief description of the required tools to make this much more comfortable and safer. I will also talk about the common mistake that most people made, and I don’t want you to make on your project.

How to Grind Concrete with an Angle Grinder

Grinding Concrete with an Angle Grinder

The first thing that you need is a really great HEPA vacuum. You will be using the HEPA vacuum or high-efficiency particulate air vacuum because of its efficiency and the extra plug outlet. You can plug in your power tool, in this case, an angle grinder, and then turn on the power setting to the outlet.

Now, whenever you turn on the angle grinder, the HEPA vacuum will also turn on. You can get your grinding and get the dust vacuumed simultaneously.

You should look for some additional features on the HEPA vacuum; first, the power cord should be super long. So if you need to have the HEPA vacuum moved somewhere, having a long cord will surely help.

The next feature you should look for is a long hose.  The length of the hose allows you to keep the vacuum at a safe distance from your workplace. Especially when you’re grinding a floor, or you’re cutting tiles.

It almost goes without saying, but if you’re going to grind concrete floors, you need an angle grinder.  You can use a four-and-a-half-inch angle grinder, but this isn’t the most essential tool that you need. The most important fact of grinding concrete is the dust shroud. With the surface grinding shroud, you can use this with a grinder up to 6 inches size, and you can also use it for wheels/blades up to five inches.

This brings me to the next tool that you need. For an angle grinder to smooth concrete, you will be using the thinset removal bit. This is a grinding wheel specifically for removing thin-set, you guess that, and you can use it also to remove paint and any other superficial contaminant on top of your concrete.

When you combine a HEPA vacuum, a grinder, a thinset removal bit, and the surface shroud, these four components make grinding concrete much safer and faster, but that’s not the end of the story.

Admittedly sometimes you might forget personal safety equipment. But whenever you’re grinding concrete floors, you don’t want to do that. So make sure you get some safety glasses and hearing protection, and then a professional’s favorite piece of protective equipment is the silica dust respirator. Probably the best 40 to 50 bucks you’ll spend on a respirator. This is great, and you can use this to grind down concrete tile anything with silica in it. This is going to prevent that silica from getting into your lungs. So make sure you get one of these.

Grinding Concrete with an Angle Grinder

While grinding, the most common problem with the concrete floor is the presence of paint overspray along the perimeter of the floor. That’s never good, especially if you’re going to be bonding a self-leveler to the concrete. You also might have a little bit of joint compound here and there, not typically a big problem, but you want to get all of it removed from the surface of the floor because it’s going to be a bond breaker.

Now, if you’re removing ceramic or porcelain tile from concrete, there is a high chance that you’re going to have a thin-set residue on the top of the floor. So, you need to remove that. If you have a little bit of residue and have a vinyl tile on the concrete’s surface, the first thing you need to do is to remove all the dust and any contaminants resting on the top of the floor.

Secondly, you’re going to need to install the dust shroud on your grinder. Now the cool thing with this dust shroud is it will work with a variety of different grinders. This dust shroud comes with a metal connector. There are three screws that hold it onto the Shroud. Basically, if this connector doesn’t work with your grinder, you can swap it out from one that does work.

You’ll have to remove the guard from the grinder, and then the shroud slides into place. Sometimes it can be a little bit troublesome to fix, so you just have to loosen the screws to get it in place; that’s how it fits on to the grinder.

All you need to do is tighten these screws. There are only two screws on the front. And then, finally, you want to install your thinset removal bit into the grinder. To set this thin-set removal, simply just twist onto the grinder’s spindle, and that’s it.

Always try to start your grinding project from the corner of your room. Have the thin set of removal bits facing downward, turn the angle grinder on full power, & engage the bit into the concrete’s surface.

There will be no issues whatsoever removing the paint overspray or the joint compound. And as you can experience while working, the nice thing with this surface guard is it’ll fit tight up against the wall door casings or adjacent flooring. You will surely be impressed with the dust removal capacity of the dust shroud and the vacuum. It’s awesome, I highly recommend this setup if you don’t currently have one.

Most Common Mistakes People Make While Grinding

Now there are two common mistakes that most people make; I don’t want you to make those.

Number one, when you’re grinding the surface of concrete surely you’re going to have some residual dust that remains on the surface. When you see that residual dust, vacuum it so that you’re not hitting it with the thin-set removal bit. When you hit it with the thin-set removal bit, you’re going to send a little plume of dust in the air, and that’s never good. So tip number one is always to remove any residual concrete dust that remains on the floor tip’s surface.

Number two, if you feel your angle grinder getting hot, allow it to cool down for a minute or two. Maybe you are kind of on a tight schedule and you kept on going through, removing all of the paint off the floor and any of that joint compound. Unfortunately, there is a high chance that the angle grinder will catch on fire. Which you didn’t anticipate. Keep an eye on the machine’s heat; most of the time, people mistook the smoke as dust. So don’t make that mistake. If you feel the angle grinder getting hot, just stop and allow it to cool down.

Final words

I hope you got an overall idea of how to grind concrete with an angle grinder. It’s pretty easy if you just follow the proper technique and are equipped with the right tools and accessories. Best of luck.

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