POWER TROWEL

Today's Accessory Choices of Power Trowel, Floating and Finishing

Jeff Snyder, Sales Manager, Wagman Metal Products, Inc.

The art of placing and finishing concrete can be done with skilled craftsmen, a straight two-by-four, a hand float and a hand trowel. A laser screed and ride-on power trowels sound like better choices when you need production and flatness. Of course, skilled professionals (along with proper equipment and accessories) are necessary to finish the job on time and to meet the specifications. Today's trowel machine accessory options can be the finishing utensils that "touch the canvas," so to speak.


Attachable Float Blade
FLOATING
After the bleed water dissipates and the weight of the operator's footprint leaves no more than an 1/8" depression, the concrete can be power floated. The floating process knocks down imperfections, pushes down the larger aggregates and prepares the surface for finishing. The available options for power trowels are float blades, float pans and combination blades.

Float blades are made from a low-carbon steel and are always used in a completely flat position. Float blades will typically have a slight bend on all four sides so they do not dig into the concrete. Depending on the mounting system, float blades may clip over finish blades or mount directly onto the trowel arms. Even when ride-on power trowels are used, some contractors prefer to make a first-floating pass with a walk-behind trowel. When flatness and production issues arise, riders with float pans become the equipment and accessory of choice.


48-inch Float Pan
The introduction of float pans, or "disc" technology, originally came from Europe. Float pans are typically used on ride-on trowel machines for the purpose of achieving more production and flatter floors. The coverage area of a float pan is at least the size of the trowel machine's diameter path with the blades attached. The size and coverage area of a pan verses float blades easily illustrates the production and flatness difference. The increased area touching the concrete causes more torque, thus, more power is needed. Thus, it is not recommended to use float pans on walk-behind trowels too large for the operator to handle. A float pan can extend the window of floating because of the size and coverage area.

There exists a myth that you can float early with pans because of the weight distribution, but this may merely push material around unnecessarily and flatness will suffer. Another myth is that a pan needs to be flat. However, a proper "dish" to the pan helps provide equipment performance and flatness. A pan that cannot keep a dish or is too flat may "oil can," causing the equipment to bog down and become difficult to steer. On the other hand, too much dish will be easier to steer, but coverage and flatness may be sacrificed.

Float pans and float blades are similar in thickness, but may not be made from the same type of steel. Proprietary specifications on the raw material steel and flange design allow manufacturers to differentiate themselves. Flange design and type of steel directly make an impact on how well the pan holds its shape for performance and pan and blade life.


Combination Blade
There are two basic clip systems for float pans. A "z-clip" style simply allows a pushing point for the trowel blades to spin the pan. Another type of clip, sometimes referred to as a "safety-catch", has a bar that goes over the trowel blade and helps secure the pan under the trowel when being moved. With the "z-clip" system, extended wear may be achieved by rotating the pans (similar to rotating car tires).

A combination blade, made from high carbon steel, can provide both floating and finishing functions. By comparison, it is smaller than a float blade and larger than a finish blade. For the floating function, combination blades are run flat, with the leading edge and sides having a slight upward bend so they do not dig into the concrete (similar to the float blade).

For the finishing function, the trailing edge is flat to give a hard, flat finish. The combination blade is used in one direction and cannot be reversed, unlike a finish blade. Some contractors like to use a combination blade, early on in the finishing process after pan floating, to close the small aggregate drag marks that may be left from the floating process.

FINISHING
After floating, when the concrete has set enough, it is time for finishing.


Finish Blade
A finish blade is made of high-carbon steel which provides a flex and swiping action to densify the concrete. Finish blades are always pitched, at least slightly. The pitch is increased as the concrete becomes harder. An advantage of a finish blade is that there are two edges available for wearing. After the one side wears out, the blade may be turned around for a fresh new edge. Wide finish blades (eight-inch) have become popular with their larger surface area for early finishing after panning. For early finishing, the wide finish blade may be more economical than a combination blade because it can be reversed.

There are several thicknesses of high-carbon steel available for finish and combination blades. For example, Wagman Metal Products, Inc., has blades available in three types of steel:

Original Silver, Wagman Blue XL® and Wagman Gold Pro® series. The Silver series has the most flex and may be used on walk-behinds and riders. The Blue XL, developed in 1993, is thicker than the Silver series and provides 15 to 25 percent longer life, as well as maintaining a desired flex. The Gold Pro series was developed in 1986 to meet the demands of ride-on power trowels. They provide 25 to 50 percent longer life than the standard silver blades. Gold Pro and Blue XL blades provide longer blade wear and reduce the number of blade changes, which lowers labor costs. As a tip, a thicker blade may not always be better depending on the desired flex. For example, a new set of Gold Pro blades may be too stiff to use on walk behind trowel machines.


Plastic Blades
PLASTIC BLADES
As the concrete tightens, high carbon-steel blades will leave black burnish marks. Sometimes the burnish marks are unacceptable, especially when the concrete floor is left exposed. Finishing with plastic trowel blades has become the solution to this problem. Plastic blades are available in both combination and finish styles. To avoid any possibility of burnishing, especially on light-colored and light-reflective floors (i.e. L&M QUARTZ PLATE FF LIGHT-REFLECTIVE), plastic blades are a great choice. New natural concrete color floors that will later receive a stain will also benefit from the uniform finish that plastic blades leave.

To achieve a polished floor with the burnish-free look (especially with light-reflective colors) use the plastic combination blades for floating and early finishing to close up the drags. Then complete the polish with the plastic finish blades.

To achieve the hardest finish possible with a plastic blade, a steel backing has been introduced. Steel-reinforced plastic blades are available to provide the stiffness and desired flex point, creating a harder surface. The steel backing also provides support to meet the demand of the heavy riders.

Trowel blades and float pans will continue to develop as the industry demands continue to change.

About the Author:
Jeff Snyder (CSI, CCPR) presently serves as Sales Manager for Wagman Metal Products, Inc., which has been manufacturing trowel blades since 1963. He is a Member/Certified Construction Products Representative of the Construction Specifications Institute (CSI). Jeff has served in the industry as Manufacturer Sales Representative, Distributor Sales, and Consultant since 1988.

Jeff Snyder can be reached at
Wagman Metal Products Inc.
400 South Albemarle St. • York, PA 17403
www.wagmanmetal.com • email: jeff@wagmanmetal.com • 717-854-2120

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