Use 30/46 grit for heavy leveling and 60/80 for removing laitance and trowel marks without deep cuts. Move to 120/150 only when the slab is already flat, and do not skip grits on rough concrete.
Start with the coarsest grit that does not cut deeper than your target. For removing laitance and light trowel marks, 30/46 or 60/80 metal bond is the sweet spot: it opens the surface without carving deep gouges you later have to grind out.
Do not skip grits on a rough slab — jumping from 30 to 150 leaves a scratch pattern the finer pads cannot resolve. A double-S segment disc in 60/80 gives a consistent scratch depth that is easy to follow up with the next grit.
Use a 2 m straightedge. Once gaps under the straightedge are within the floor's tolerance and the surface texture is uniform across the whole area, stop and move up a grit. A triple-round segment disc wears evenly, so the scratch pattern stays consistent across large rooms.
A: Only when the slab is already smooth and you are refining. On rough or ground-new concrete, skipping leaves a scratch pattern finer pads cannot resolve.
A: If segments glaze and stop cutting, the bond is too hard; if they wear flat in under half a set, it is too soft. Match bond to concrete hardness.
A: Dry grinding with a HEPA vacuum is standard on polished concrete jobs; wet grinding is mostly used for stone and edge work to control dust and heat.
A: Change the whole set together once segment height drops by half or the cut rate slows. Mixing new and worn plates causes uneven scratch patterns.
Choosing the right bond, grit and technique for your concrete job saves tooling cost and avoids rework. Match the tool to the slab, work in the correct grit sequence, and keep plates balanced — the floor will tell you when you are ready for the next step. Contact JOY TECH for tooling recommendations matched to your machine and concrete hardness.
