Refinishing your brick fireplace will bring new life to not only the fireplace, but the room the fireplace is in as well. You may be thinking about painting the fireplace or covering it with a glaze. Before doing so, you will have to sand the brick. Use sandpaper in the 100- to 220-grit range. Start with a lower grit sandpaper and move up.
Start sanding your fireplace with a 100-grit sandpaper--medium grit. It will remove any layers of paint or glaze on the fireplace. The lower the number of the sandpaper, the rougher the paper is. After you have removed the layers, move up to a 150-grit sandpaper to start smoothing out the bricks. Grab a new piece of sandpaper when the paper starts to get too smooth or rips.
Use a 200- or 220-grit sandpaper, very fine, to make the fireplace smooth before applying a paint, glaze or other finish. The higher the sandpaper grit number, the smoother the finish surface will be, and the smoother the sandpaper will be.
Use a sanding block for the sandpaper so you do not hurt your hands. You can also use a power sander. Practice with the power sander before using it on your fireplace. Get used to the sander and how to change the sandpaper. Purchase sandpaper that has a black coating. The black coating contains silicon carbide, and it will last longer than regular brown sandpaper.
Use a smaller foam-sanding sponge to sand areas where the power sander or large piece of sandpaper can't reach. Foam-sanding sponges can also be reused--wash them with soap and water and dry them with a paper towel.