A concrete grinder is used to remove old basement floor sealant to prepare the surface for tiling, resealing, or simply polishing. The machine can also remove old paint, rough concrete surfaces, and a stained concrete surface.
Step 1 - Preparation
Rent, borrow or buy a concrete grinder (Fig. 1). Before using the machine, make sure to read the manual thoroughly, especially if it is your first time. Determine how much energy the machine requires. Be sure to know how to attach and detach the grinding pads from the unit as well. Determine how to use the machine to grind the concrete layers evenly. Do not turn on the machine unless you understand how to operate it.
Step 2 - Clear Out the Concrete Surface
Clear out every object on the basement floor. Remove any debris and sweep the floor clean. Doing so will ensure that nothing will interfere with the operation of the grinder and the pads during the grinding operation.
Step 3 - Provide Sufficient Ventilation
Although the equipment is connected to a dust vacuum, there is still a good chance that dust will become airborne. Wear a respirator and eye goggles, and open all windows and doors to provide good ventilation inside the working area.
Step 4 - Prepare the Grinding Pads
Use a coarse grinding pad for the first grinding pass. The pad is usually 40-grit; however, it is best to read the manual to determine the correct pad to use during coarse grinding. To create a glossy and well-polished finish, use a finer grinding pad. Attaching the grinding pads to the unit may require a wrench (Fig. 2) or a hammer. Check for the manufacturer’s instructions for more details on how to attach the pads correctly.
Step 5 - Coarse-Grinding the Concrete
Attach the coarse grinding pad (Fig. 3) and the vacuum hose at the bottom of the unit. Determine the starting point and position the unit in that location. Switch the vacuum on and switch the grinder to its grinding mode.
Wait for it to rev up to its maximum rotational speed. When that happens. its rotating speed and sound will stabilize at a steady rhythm and pitch. Lower the grinding pad onto the floor and move the unit in either a small circular motion or from side to side.
Always move in a straight line. Apply light pressure to the pad so that it will grip the floor surface. When the end of the line is reached, switch off the grinder and move it to the next row. Follow the same procedure until the entire sealed layer is removed.
Step 6 - Polishing the Rough Concrete
Exchange the grinding pad for a finer one that is designed for polishing. Go through the whole grinding process row by row until the floor is evenly smoothed. Turn off the unit and the vacuum. Sweep the floor to remove any leftover debris. Inspect for any uneven surfaces and re-grind if necessary.