Polish a floor with a 110V grinder

This step-by-step guide will show you how

Did you know a 110V grinder can prep and polish a concrete floor? National offers two different 110V machines for prepping and polishing a concrete floor. The Helix is a versatile 110V grinder capable of reaching a 400-level polish.  With grinding head pressure of about 130 lbs. it is a lightweight solution to basic prep and polishing.  Our 8274-4 is a heavier machine with a higher RPM motor and has a full set of polishing pads available.

Tooling options

Regardless of your grinder choice, you need to prep and profile before you can polish. National’s 110V grinders both use the same planetary tooling, and we have a variety of prep diamonds available.  Using these diamonds in a step-by-step fashion will get your concrete set up for polishing. 


The first 4 steps in polishing your floor are the most important.  It is so tempting to speed up the process and skip over a step.  Don’t do it.  Getting to the polishing stage and realizing you can see scratch marks means you will have to start over.  Save on your labor cost, your tooling, and machine wear and tear by moving through each step.

Using the Helix or 8274-4 grinders to polish your floor, start with a 16-grit full bar diamond as your first piece of tooling. It opens up the surface of the concrete, gives it porosity, and removes any sealers already in the concrete.  The next step is 30-grit full bar diamond. This still opens the floor but also starts to prolfile the concrete.

Profiling Diamonds

After these 2 beginning steps, move to National’s 3-segment profiling diamonds. These begin to smooth out the concrete floor and remove scratches.  Use a 30-grit then 50-grit from our metal profiling diamond series.  The machine setup for all 4 of these first steps is the same on both the Helix and 8274-4 polishing grinders. Use 2 diamonds in each holder on the satellite. Load them across from each other and load the other two spaces with blanks to protect the satellites.

Resin Pads

After completing the prep and profiling steps of your polishing job, switch to resin pads.  First, 50-grit, then 100-grit, and then 200-grit.  After these 3 stages of polishing pads, stop and vacuum your floor before putting down your hardener densifier.  This is not a liquid that National sells, but is a critical step in ensuring a beautiful floor at the finish. The porosity of the concrete you just opened up is going to soak up the hardener densifier.  It will make the surface of your floor much harder with a higher psi surface.  Follow the directions on the bottle – every product is slightly different.

When that is dry – move to a 400-grit polishing pad. On your Helix floor grinder, this is where your steps will stop.  At this point you will have gotten a 400-level polish and a beautiful finish on your floor.  The 8274-4 is a heavier machine with faster RPMS and can continue on through the 800-grit, 1500-grit, and 3000-grit pads. At the end, put down a lithium protective finish. It seals the floor and removes some of the light resin marks that may be left behind. 


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