Concrete Grinding for Countertops

Grinding

• Grinding isn't essential for concrete casting and installation. If the mold gives you the right shape, texture and so forth, you may find it unnecessary to grind it -- if so, then all the better. If you want to expose the aggregate or if your designs incorporate any decorative add-ins, however, grinding is essential. You can also use grinders to remove any minor imperfections or blemishes from the surface.

Tools

• Hand-finishing pads are simple tools that resemble sanding blocks; their rough surface abrades the surface of the concrete much like sandpaper on paint. You can use them to clean up, remove imperfections in tight spots and touch up the surface. For bigger jobs, a handheld electric grinder or polisher may be more suitable. Most of these devices are angle grinders with a water feed that routes water through the center of the disc on the grinder to keep the concrete moist.

Procedures

• Concrete grinders are used in conjunction with diamond grinding pads; different grits are available. Finer grits are best for polishing, while rougher grits are good for exposing aggregate. To avoid gouging, the concrete grinder should always be used with the whole face pressed flush against the concrete. Don't apply excessive pressure -- just enough to keep the disc in contact with the concrete. Higher speeds mean faster grinding.

Considerations

• Grinding concrete can create a lot of dust, so it's usually best to do it in the workshop rather than in the place where it's going to be installed. Upon installation, however, it may sometimes be necessary to grind the concrete to make sure it fits properly. It's also a good idea to start grinding with more water than you need and gradually decrease the amount of water you use. Too much water is better than too little where grinding is concerned.