How to Operate a Concrete Grinder

Concrete grinders are used in the surface preparation of concrete. There are a number of different ones available to suit different projects. The best equipment for your job will largely depend whether you need to level off a slab, prepare for new floor coverings or get that polished showroom look.

The concept of a concrete grinder is very simple. It doesn’t matter if you’re using a small handheld grinder or a bigger single head machine - they work the same way. The head rotates, grinding the surface of the concrete beneath, and different attachments can be used to get you the results you want. 

Handle positions and plugs

Most machines have adjustable handles and controls. There are three different handle positions:

1. Operating position. This is the position you use the machine in. Most of our concrete grinders are adjustable to suit different heights.
2. Tooling position. This position makes it easier to tilt the machine up so you can change the discs and pads.
3. Lifting and storage. If you’re lifting the grinder on and off trucks, putting the handle into the lifting position makes it easier to move around and store.

The concept of concrete grinding is basically the same as for woodwork or metalwork. You start off with the most abrasive plugs then move down to softer discs. If you’re polishing, you’ll want to finish off with resin pads.

Dust control

As well as checking you have all the plugs and discs you need, you’ll also need to make sure you have some dust control measures in place. Most concrete grinders come with a vacuum attachment to remove dust as you go. Another option is to dampen the surface you’re working on with water from the hose, but be aware this will create a slurry so can be a very messy process. You can’t vacuum if you’ve used water, so it’s one or the other.

To operate the machine

1. Check you have the right plug attachment (more about changing plugs and discs below)
2. Put the handle setting into operating mode and adjust it to your height. You want to be comfortable using the machine and you may also need to push it down and take a bit of weight off the head as you go, depending on the surface. Our machines come with adjustable weights that you can add and move around if you need a bit more or less pressure on the grinding head.
3. Check your vacuum hose is in place, if you’re using it.
4. Tilt the machine back slightly before you turn it on to free up the grinders from the surface.
5. Press the green start button.
6. If the machine trips out, the overload button will pop out. Let the machine cool down for a couple of minutes, then push the button back in and keep going.

Changing the discs and pads

Many of our machines come with a number of different attachments. Each disc or pad is suited to a different stage in the concrete preparation process. The plugs are for the heavy grinding work, discs for finer work and then the pad is used for polishing.

As you progress with your concrete surface preparation, you will need to switch plugs and discs. Switching plugs is very easy (we always recommend you wear gloves). Get a hammer and tap it on the plate near the plug and the plug should pop out. To put plugs in, just push them with a bit of force and they will bind in.

When it’s time to change from plugs to a disc, take the plug out and put in the magnetic plug that comes with the discs. Next, put the insert through the disc and then attach the disc to the magnetic plug.

Tip: When changing discs back to plugs, make sure you take magnetic plugs out.

To change the discs on a smaller grinder/edger you’ll need to find the locking pin on the side of the machine to lock it in place. Once locked, take a spanner and use it on the centre nut to remove the disc. Replace with the new disc and tighten up again.

Kennards Hire has the experience and know how to help you with your next project.  Get in touch with your local branch today by visiting contact us.