How to choose a power trowel for concrete: diameter and engine

To smooth a fresh concrete floor, the power trowel is chosen by the surface to be covered: for small rooms and finishing work, single-rotor models of 600-900 mm are enough, while for industrial sheds and yards you need larger diameters or the double power trowel. The engine, electric or petrol, depends on the location: electric indoors, petrol or diesel where there is no mains power. In the collection the diameters range from 600 to 1,200 mm for the single-rotor machines and up to 1,900 mm (2 x 950) for the double ones.

The types

• Single power trowel: one rotor with a pan or blades. It is the most common machine, like the E-Power 24 inch Barikell or the MX FUEL 600 mm Milwaukee.
• Double power trowel: two rotors, covering more surface with each pass. For example the MK8-90 High Rider Barikell or the double trowelling machine KD190 Breaker.
• Trowelling machines for sand-cement screed, for concrete and for working up to walls: versions for different surfaces and for working right up against walls.
• Vibrating screed and vibrating finisher: they level the pour before the power float.
• Surface preparation machines: such as the Seacopter 90 Sea Technology.
• Spare parts and accessories: sets of finishing blades, combination blades, float pans, power units and transport trolleys.

How to choose by job

If you are torn between two diameters, think about who will use the machine: a single 900 mm moves with one operator on foot, but on the pour for a whole shed the times lengthen considerably. Before choosing, work out how many square metres you have to close in a day, because concrete does not wait.

The features to look at

• Diameter: 600, 750, 900 and 1,200 mm for the single-rotor machines, up to 1,900 mm for the double ones. The larger it is, the fewer passes are needed, but the more it weighs and the harder it is to manoeuvre.
• Engine: petrol (Honda GX160, GX270, GX390, Lombardini-Kohler CH270), diesel, single-phase electric 230 V or three-phase 400 V. Check that the site has the right power supply.
• Power: from 0.36 kW to about 8.7 kW (11.7 HP). More power is needed for larger diameters and for double machines.
• Number of blades: from 4 to 12 depending on the machine. Float blades close the surface, finishing blades refine it.
• Weight: the largest machines reach 288 kg, while blades and spare parts weigh a few kg. Think about transport too, and loading onto the van.

Common mistakes

• Starting on the pour too early: the concrete must bear the weight, leaving only a light footprint.
• Starting straight away with the finishing blades: start with the pan or float blades and then move on to the finishing blades.
• Suddenly increasing blade pitch and speed: do it gradually.
• Not washing the machine at the end of the day: the concrete hardens on the blades and pan.
• Using worn blades: the surface comes out wavy and does not close.

Frequently asked questions

When do you run the power trowel over the concrete?

When the pour bears the weight of the machine and leaves only a light footprint. Before that, the machine sinks in; after that, it no longer smooths.

Is an electric or a petrol power trowel better?

Electric indoors and where mains power is available, petrol or diesel on open sites. An internal combustion engine needs ventilation if you work in enclosed spaces.

How many blades are needed?

It depends on the machine: from 4 to 12 depending on the model. Always use the number specified by the manufacturer.

Do I need a vibrating screed?

It levels the pour before the power float goes over it and helps to achieve an even surface. The power trowel then closes and finishes it.

Pan or blades?

The float pan is used on the first pass to close the surface. The finishing blades are used to refine it.

You will find machines, blades and spare parts in the vibrating screeds and power trowels for concrete collection: for advice on the right machine or for a quote, write to the AMES technicians.