Trowel Power

Sept. 1, 2002
Timing is crucial in the concrete flatwork business. The quality of the floor is established within the period between placing and curing of the concrete.

Timing is crucial in the concrete flatwork business. The quality of the floor is established within the period between placing and curing of the concrete. Concrete contractors know their livelihood depends on their ability to have the right machine ready at the right time.

This is where the rental center enters the scene. Power trowel rentals can be a win-win situation for both the rental center operator and contractor. The time saved on the job by renting a power trowel can far outweigh the actual rental cost of the machine and will keep the contractor coming back for more trowel rentals.

Power trowels are used for both floating and finishing large slabs. Compared to ordinary hand tools, power trowels significantly increase production and reduce costs by their ability to cover more square footage of slab area per day. At the same time, they improve the quality of the concrete surface and help maintain flatness of the slab. Power trowels are divided into two styles, walk-behind and ride-on.

Walk-behind trowels typically have one rotor with four blades, are powered by a gasoline engine and are available in 30-, 36- and 48-inch blade diameters. Ordinarily, hand tools might finish 300 to 600 square feet per day where as a 36-inch walk-behind power trowel can finish 700 to 1500 square feet per day depending on job circumstances and weather conditions.

Ride-on trowels typically have two rotors each with four or five blades, are powered by one or two gasoline engines and are available in 36- and 48-inch (single rotor diameter) models. Ride-on models can dramatically increase production. Typically, a ride-on can cover three to five times as much concrete compared to walk-behind units. Depending on the jobsite conditions and operator proficiency, one ride-on model can replace three to four walk-behind units. Another advantage with ride-on units is improved quality and flatness off the slab.

Ride-on trowels operate in two different configurations, overlapping and non-overlapping. Typically, the non-overlapping position of the blades requires higher torque and can accommodate pans during the floating operation. The overlapping position is often used at faster rotor speeds and provides seamless coverage during the finishing process.

Besides the trowel themselves, rental center operators need to offer the correct blades for the job. In general, blades are interchangeable between most brands of walk-behind and ride-on power trowels as long as both are the same size, i.e. 36- or 48-inch. Standard finish, combination and float blades are made of high quality steel and bolted to the trowel arms.

Float blades are 10 inches wide, with the edges turned up so the blade won't penetrate or tear the fresh concrete surface. These blades are the first blades used on fresh concrete and are typically rotated at a relatively low rpm. Float blades should be adjusted to little or no pitch (flat on the surface).

Finish blades are sometimes called troweling blades. They are 6 inches wide with the ends turned up and are typically rotated at a high rpm. Finish blades follow the floating operation. They apply more pressure to densify the surface as the concrete hardens. They are used to complete the power troweling operation.

Combination blades are 8 inches wide, with the leading edge and both ends turned up. Some power trowel users prefer to use these blades for the entire job, floating (low rpm) and finishing (high rpm). They believe the combo blades are better choices than the finish blades because the blades, 2 inches wider, provide more flexibility. One set of combination blades lasts 25,000 to 30,000 square feet if used from start to finish, 50,000 to 100,000 square feet if used for finishing.

Float pans were first used on ride-on trowels in the early 1990s because of the growing need for flatter floors. They are generally used only for the power floating operation (instead of float blades), and are typically rotated at slower speeds. Pans are not used for finishing because they do not close up the surface on concrete as well as blades do. Pans are also not recommended for larger, 48-inch walk-behind trowels because excessive drag and friction makes controlling the machine difficult. Pans can be used on any size non-overlapping ride-on unit. Pans are round, slightly convex on the bottom, made of steel and have the outer edge turned up to prevent the pan from digging into the concrete.

Bob Becher is concrete product manager for Wacker Corp., Menomonee Falls, Wis.

Target

Target introduces two new models of the MC 18 small concrete saw. The saws feature improved weight distribution, which holds the blade in the cut and provides consistent depth at increased forward speed. The reinforced box type front axle assembly model strengthens overall structure, increases stability when raising and lowering, improves sawing performance and offers larger front wheels with bearings. The positive screw feed model raises and lowers the blade quickly and easily, has a spring assist feature that helps raise the blade out of the cut faster with minimum effort, provides a manual lock that keeps the blade at a fixed depth and has a stop switch on the handle.
Circle 144 on reply card.

Hypac

The new C784 tandem-drum vibratory roller from Hypac offers an 84-inch drum width, higher vibration frequencies and increased centrifugal force. Featuring operating frequencies of 4,000 and 3,400 vpm, the new C784 tandem-drum vibratory roller can achieve working speeds up to 4.5 mph while maintaining 10 impacts per foot. Equipped with a 205-hp Cummins diesel engine, the roller can generate 34,655 pounds of centrifugal force in low amplitude and 41,235 pounds in high amplitude. The roller also features 54-inch diameter drums to help minimize shoving.
Circle 145 on reply card.

RGC

The RGC HydraCutter C150 hydraulic chain saw cuts masonry, stone, concrete, reinforced concrete and other aggregates. Available with a 15- or 20-inch bar length, it is designed for plunge, bottom, trim and notch/corner cuts without over-cutting.
Circle 146 on reply card.

USF

The Sawtec FS-150 and FS-60 walk-behind air saws for cutting concrete or asphalt are heavy-duty, portable saws that are lighter weight than comparable gas saws, and offer lower maintenance because there are no gas lines or carburetors to clog. The units cut dry, wet or with a vacuum guard. A built-in adapter enables either unit to be connected to a water hose for dust suppression or an optional self-contained water tank is available.
Circle 147 on reply card.

MK Diamond

MK Diamond announces the release of the CX-3 Concrete Xtreme Saw. With easy access controls, the CX-3 has positive depth control and cutting depth of up to 5 1/2 inches. It also features left and right side cutting capacity with a hinged blade guard that allows users to cut within 1-inch of a wall or curb.
Circle 148 on reply card.

Arrow-Master

Arrow-Master introduces the only direct-drive, walk-behind, power trowels in the concrete finishing industry. The F-Series, direct-drive trowels have a lower center of gravity, which provides a balanced power transfer. That means less wobble and side torque, which yields a smoother, flatter finish with easier handling. Direct-drive also means more power to the blades. Engine horsepower is transferred directly to the gear box and spider, providing consistent, reliable power. The fully enclosed spider assembly eliminates concrete build-up around the trowel bottom and protects the blade-arm components and pitch-control mechanism from damage due to neglect and everyday wear and tear. F-Series power trowel are manufactured in 30-, 36- and 46-inch troweling diameters, with three or four blades, and a variety of engines.
Circle 149 on reply card.

Stihl

Available with either 12-inch or 14-inch wheel guards, the TS 400 Stihl cutquik now comes with a water attachment as a standard feature, giving the operator the choice between wet and dry cutting. Other features include innovative filtration design, intellicarb compensating carburetor and a power-to-weight ratio of 64 cc engine to 19.6 pounds. Wet cutting controls dust emission at the source, providing for less clean-up and less maintenance of filters, starter ropes, pistons and cylinders. This procedure also provides for longer diamond-wheel life, as water acts as a coolant to help reduce diamond-wheel wear.
Circle 150 on reply card.

Edco

Designed for making contraction joints, repairing slabs or cutting asphalt, Edco's dual-arbor DS-16A street-saw has been redesigned to accommodate 14- to 18-inch diamond blades. A larger screw-type depth control makes it easier to raise and lower the blade for cutting. Design improvements allow belt changes without blade shaft disassembly, so arbor alignment is not compromised. The DS-16A retains its heavy-duty box-frame construction for faster cutting and greater durability.
Circle 151 on reply card.

Stone Construction Equipment

Two new 2-cubic foot concrete mixers have been added to the Bantam Weight series of the Stone Champion line, the 25 CMP and 25 CMPT. The 25 CMP is a wheelbarrow style mixer and the 25 CMPT is a pedestal style mixer. Both models feature an easy-to-clean poly drum and steel mixing blades. Featuring a V-Belt to a machined gears drive system, they are powered by a 1/3-hp electric motor.
Circle 152 on reply card.

MBW

MBW announces the addition of the walk-behind Quik-Screed to their line of concrete working and finishing equipment. Available in 8-, 10- and 12-foot lengths and has a magnesium blade that is lightweight, strong and easy for cleanup. The float blade is specially contoured to provide uniform, smooth surfaces and is designed for a more consistent vibration that extends across the length of the blade.
Circle 153 on reply card.

Multiquip

Multiquip's new SlabSaver concrete saw, FCG-1, is suited for commercial green and cured concrete cutting, asphalt cutting as well as decorative work. The saw offers a front and rear pointer that drops into the cut to ensure a straight line, polyurethane wheels with permanently sealed ball bearings, a 3/4-inch blade shaft with greasable bearings and a 1/8-inch steel plate frame that resists bending or warping. The FCG-1 is powered by a 6.5-hp Honda GX200 engine and cuts up to 3 ¼ inches deep with a 10-inch blade. It also accepts 5, 7, 8-inch and V-groove blades.
Circle 154 on reply card.

Sakai

SW300, SW320 and SW330 are a new line-up of mid-sized, double drum vibratory asphalt rollers by Sakai America. These new machines offer 4000VPM vibration speed, which allows for the choice of increasing the ground speed while maintaining the customary 10 to 12 impacts per foot spacing required for density and smoothness. A typical ground speed can also be maintained, increasing the number of impacts per foot and perhaps allowing density to be achieved in fewer passes. Additional features include a counter-rotational eccentric system, a hydrostatic, multi-disc braking system and high 21 1/2-inch curb clearances on both sides of the machine.
Circle 155 on reply card.

Diamond Products

The CC6000D from Diamond Products features a patent-pending design with a differential drive system that allows for easy maneuvering by pivoting the saw on its rear wheels. It features a 65-hp Wisconsin gas engine, fits through a 30-inch door, has hydrostatic transmission with enclosed differential, provides positive drive to both rear wheels for maximum traction and has a maximum cutting depth of 14 3/4 inches with a 36-inch guard. The saw comes standard with quick-release bladeshaft/flange, slip-on blade guards, quick-release 10-inch rear wheels, double concave roller bearings, telescoping front pointer and 3 position handlebars.
Circle 156 on reply card.

Putzmeister

With its four-section boom, the Putzmeiter 58-meter concrete boom pump provides a 188-foot, 1-inch vertical and 174-foot horizontal reach, essential for long distance or difficult-to-reach jobs. Using its high-pressure .20H pump cell, up to 260 cubic yards an hour volume is attained. The model features free-flow hydraulics for smooth, controllable pumping. When fully deployed, the outrigger footprint is 32 feet, 9 inches in the front and 34 feet, 9 inches in the rear. Additional characteristics include auto lubrication of the boom, pedestal and hopper, along with two loading decks for handling pipe and accessories.
Circle 157 on reply card.

Bosch

Bosch Power Tools introduces the 1773AK 5-inch concrete surfacing grinder with the most comprehensive dust removal system. A built-in dust chute connects to a vacuum hose for better, more efficient debris removal. In addition to the dust removal system, standard diamond cup wheels and a patented brush-ring for dust-free work provide unmatched debris management as well as cleaner and safer dust extraction. This tool weighs less than 6 pounds and includes a wrap-around side handle for easy handling and an automatic restart protection that guards against automatic start-up after a power failure, ensuring that the tool is only intentionally powered on each time.
Circle 158 on reply card.

Hilti

The Hilti DD 160E is fast cutting, simple to operate and requires no tools to change bits. It drills 1- to 9-inch diameter holes through steel-reinforced concrete and offers three speeds. The DD 160E's modular design makes it easy to mount on the wall.
Circle 159 on reply card.

DeWalt

DeWalt's new D25900K heavy-duty electric SDS Max demolition hammer has a powerful 14-amp motor with Anti-vibration Control that dampens vibration and reduces user fatigue. Designed for concrete, demolition, plumbing, electrical, HVAC, waterproofing and general contractors, the D25900K hammer has spring-loaded dust seals and is specifically built to keep dust out for longer motor and tool life. With its variable speed impact control settings and hard hitting hammer mechanism, the D25900K produces 3.7 to 18.5 feet per pounds of impact energy and can be adjusted from 1,020 to 2,040 blows per minute for fast material removal and better user control. The model has a large rubber handle and features a convenient lock-on rocker switch. Its compact in-line design and barrel-grip shaft make the demolition hammer easy to hold for both horizontal and vertical applications.
Circle 160 on reply card.

Wacker

This year new 36-inch and 48-inch models have been added to the Concrete Ride-on Trowel line. A 24-hp Honda engine powers the 36-inch model, and the 48-inch model is powered by a 31-hp Vanguard and features two, 5 blade rotors and two spray retardant nozzles. Wacker's new ride-on models feature a unique overlapping and non-overlapping operation on the same machine. By changing the blade position on the trowel arm, the machine can be reconfigured in minutes to accommodate the job. Both high-speed models feature a special clutch design or turque converter that allows the operator to change the trowel's blade speed to match the condition of the concrete without mechanical adjustments.
Circle 161 on reply card.

Terex

Terex presents a new poly drum for mortar and concrete mixers. Features include a heavy-duty tubular steel frame, solid engine base, adjustable start stop clutch to engage and disengage paddle shaft, and a double belt drive system. A heavy-duty front pedestal prevents bending and the tight, heavy-duty grid design resists bowing. The model also includes a louvered engine cover, which provides better ventilation and eliminates water introduction.
Circle 162 on reply card.

General Equipment

General Equipment Company's 190C Cut-r-tach rotary asphalt cutting attachment is specifically designed as a heavy-duty, high production solution to a wide range of asphalt cutting projects. The 190C clamps directly to the buckets of tractor loader backhoes and wheel/track type loaders without special tools, modifications or adapters. Its patented twin screw clamping mechanism guarantees a tight fit in both forward and reverse cutting directions. A 19-inch-diameter cutting blade yields a maximum asphalt cutting depth of 5 1/2 inches. A blade life in excess of 25,000 lineal feet, it is field replaceable without disturbing bearings or seals. The Cut-r-tach is capable of cutting up to 6,000 lineal feet per hour in high-density asphalt and is a proven, highly productive alternative to conventional sawing and jackhammering methods.
Circle 163 on reply card.

Kraft Tool

Kraft Tool introduces new ProForm trowel and float display. Kraft trowels and floats are fitted with ProForm soft grip textured handles. Features and benefits of both trowels and floats are listed in English and Spanish.
Circle 164 on reply card.