A concrete planer is a tool used to flatten or thin the surface of a concrete slab. The size and function of the concrete planer can vary according to the size of the slab or surface being planed; some planers are quite large, and the operator will walk behind the machine as it planes the surface, while other planers are small enough to be handheld and closely resemble a large angle grinder. Concrete can be planed with dry or wet cutting; if the cutting is done dry, the planer will need to feature a dust collection filter.
Regardless of the size of the concrete planer, an abrasive wheel or cutter is used to plane the surface of the concrete. Larger planers often use carbide cutting bits, which are exceptionally hard and durable. Smaller concrete planer models may use carbide bits as well, or they may use carbide sanding wheels or other abrasive wheels designed for cutting. The cutting surface is likely to last longer if the cutting is done wet, since the moisture reduces the friction between the cutter and the surface of the concrete, but wet cutting is also likely to take much longer than dry cutting. Many users prefer dry cutting for ease and time savings.
Concrete contains silica, which can be extremely harmful when breathed in, so a dust collection system is necessary when using a concrete planer. This collection system sucks the dust created by the cutting process directly away from the point of contact, preventing it from circulating throughout a room or space. The effectiveness of the filter cannot be solely relied upon to prevent a person from inhaling harmful concrete dust, however, so a mask should be worn any time a person is operating a concrete planer or any other tool that will cause concrete dust to circulate through a space.
Concrete planers are fairly specialized tools, so if a user intends to only use the planer once or twice, it is a wise idea to rent the tool rather than buy it. Larger planers can also be quite expensive to buy, further adding to the benefits of renting instead. Walk-behind models are motorized, so maintenance will have to be done to the machine over time; if the person intends to do a fair amount of planing, buying the machine is a good option, but an occasional user can avoid maintenance costs by renting.