A power trowel, also called power float or trowel machine is a construction equipment, quite light used by all construction companies and contractors. They are used to apply a smooth surface and finish to concrete slabs before they start setting. There are two types of power trowels. The most commonly used is the hand operated, operated by person walking on the concrete pushing the trowel. The other type is the costlier power trowel is one operated by a remote control, with the operator provided with a seat, from where he can control the movement of the trowel on the concrete.
The power trowel is fitted with trowel blades. Leveling, smoothening and finishing of the concrete on are done by the trowel blades when trowel is run on the concrete. The three functions are done using three different types of trowel blades. They are the float blades, finish blades and combination blades. The first run of the trowel on the concrete is known as floating. Using the float blades, humps are removed and pits are filled up. The concrete is compacted well; the large aggregate getting embedded just beneath the surface. The float blade is so designed that it can be fitted over the finish blade. They are quite broad and are made of abrasive resistant steel. The edges are turned up, the blade is used flat. It can be used only after the concrete has set enough to support the weight of the power trowel.
Finish blades allow finishing and floating with the same set of blades. But the finish blade is not as wide as float blade. Finish blades are made of quality spring steel. The length varies to suit the diameter of the power trowel. All finish blades are reversible and can be turned end to end. The blades are tilted from three to five degrees and the trowel is run at maximum speed. The finish blades make the concrete surface hard and glossy. The purpose of running the trowel at the maximum speed is to ensure the highest pressure is applied on the slab surface. A number of runs may have to be made to achieve the level of smoothness required. Some trowels have an arrangement for locating the mounting bar, about three fourths of the distance above blade. This is done by some contractors who believe that it will give a certain degree of flexibility.
Combination blades, as the name implies, will do both floating and finishing operations. This blade is not reversible and has three edges; all turned which allows it to be used flat for the floating operation. For using it the finishing operation the edges are tilted. Another option available is the use of thicker steel for the blades so that it will increase its life.