Tools and Equipment
Tools and equipment questions ask you to select the right tool, inspect it, use it safely and maintain it. Expect power trowels, floats, screeds, vibrators, saws, compactors, pumps and lasers.
Selection basics
- Bull float (magnesium or aluminium) opens and levels the surface after screeding; a Fresno trowel tightens and densifies; wood floats leave a coarser, slip-resistant texture.
- Edgers form a radius on exposed edges; groovers or jointers cut control joints; hand trowels finish small areas and edges.
- Power trowels: walk-behind for small areas, ride-on for large; pans for initial work, finish blades for final; adjust blade pitch as the surface stiffens.
- Internal vibrators: head size matched to the section, 25 to 40 mm in thin walls, 50 mm and up in mass concrete. Rubber heads protect epoxy-coated bar and form faces.
- Saws: blade diameter, arbor and maximum rpm must match the saw; wet cutting controls silica and extends blade life.
Inspection and maintenance
Check cords and GFCI protection, guards, belts, blade cracks or missing segments, fluid levels, hose condition and pressure ratings. Grease, clean and store properly; a trowel with a bent guard or a saw with a damaged water feed is out of service.
Worked example
A 356 mm (14 in) cut-off saw turns 5,400 rpm no-load, and the only blade on the truck is marked maximum 4,400 rpm. Should it be used? Rim speed is the concern: circumference equals pi times 0.356 m, about 1.118 m. At 4,400 rpm the rim travels 4,919 m/min, about 82 m/s. At the saw's 5,400 rpm it would travel about 100 m/s, well past the blade's rating. An overspeed abrasive blade can burst. Answer: no. Fit a blade rated above the saw's spindle speed and matched to the guard.
Traps
Running a blade over its rpm rating or removing the guard. Troweling before bleed water has left, which blisters and delaminates the surface. Using a vibrator to spread concrete, causing segregation. Choosing the wrong float and producing a finish the specification rejects.