Quick Answer

There is no fixed clock time per grit level - the correct rule is to keep polishing until the scratch pattern from the previous grit is 100% gone, then step up. On a typical residential or light commercial slab, that works out to roughly 2-3 overlapping passes per grit, about 3-8 minutes per square metre at each level, with the rough grinding stages (50-200 grit) taking the longest and the final resin stages (800-3000 grit) moving fastest. Never move up by the clock alone: run your hand across the floor, wipe a test strip dry, and if you can still see the previous grit scratches, stay put. Indicatively, a full wet sequence from 50 to 3000 grit on a 50 m2 floor takes most crews 6-10 hours of machine time, including drying and inspection stops.

What Determines How Long Each Grit Takes

Before quoting time per grit, know the variables that actually drive it. Two jobs with the same slab can differ by a factor of two:

• Machine weight and power: a 65-75 kg single-disc grinder works a grit in roughly the time of a 50 kg machine; a 600 mm planetary rider-on covers the same floor in half the passes.
• Concrete hardness: hard trowelled slabs (high PSI, polished aggregate showing) resist cut and add time at every stage; soft cream slabs cut faster but can burnish too early if you rush.
• Condition of the pads: fresh resin pads cut aggressively and finish clean; worn pads drag the same grit twice as long and leave swirl marks.
• Previous stage quality: if you stepped up early at 100 grit, the 200 and 400 stages inherit that mistake and take far longer to recover.
• Water flow (wet polishing): too little water and the pads glaze over mid-stage; too much and you cannot read the scratch pattern through the slurry.

Treat the times below as reference ranges for a standard 17-inch single-disc planetary machine on normal 3,000-4,000 PSI residential concrete; adjust by machine power and floor condition.

Reference Time per Grit: Wet Polishing 50 to 3000

These ranges assume fresh, matched resin pads and steady overlapping passes. Diamond Resin Polishing Pads for Concrete Terrazzo Floor (JOY-RFP-01) keep the later stages consistent because every grit in the line shares the same bond and diamond concentration - the pad set, not your arm, controls the time.

How to Know When to Move Up to the Next Grit

The clock is a planning tool; the scratch pattern is the decision tool. Three checks take about two minutes and end most debates:

• The wipe test: rinse a 1 m2 strip clear, squeegee it dry, and look at it from a grazing angle. If the previous grit scratches show anywhere, keep working.
• The slurry check: in wet polishing the slurry should look evenly milky with no clumps. If it runs clear too early, your pads are worn and you are burnishing, not cutting.
• The edge test: machine centre cuts faster than the edges. Check the hardest-worked 10 cm near a wall; if the edge is done, the middle is done.

Moved up too early and you can tell immediately: the next stage takes three times as long and leaves a uniform swirl that never fully disappears. On rough-to-honest transitions between metal-bond grinding and resin polishing, crews often add a Copper Bond Diamond Transitional Polishing Pad (JOY-RFP-C2) at 150-300 grit to bridge the gap - it shortens the 200-to-400 recovery that is the most common time sink on real jobsites.

Wet Polishing Best Practices That Save Time

Most wasted hours on a polish job come from process, not from the grits themselves:

• Make 30% overlapping passes, and change direction (north-south, then east-west) every pass - this is what actually erases scratch patterns faster than extra time.
• Keep water flow just high enough to float the slurry; you should still be able to read the floor through it.
• Do not jump grits. Skipping 200 or 400 saves 10 minutes now and costs an hour of correction later.
• Change pads while they still cut. A worn pad finishing at half speed is the most common cause of an overrun at 1500 and 3000 grit.
• Finish edges first with the same sequence by hand or with an edge grinder using small pads such as the 3-inch Diamond Resin Floor Polishing Pads (JOY-RFP-05), then let the machine catch up - never let the big machine do work the edges were supposed to clear.

For tight corners and stair nosings, 8 Triangles Diamond Resin Floor Polishing Pads (JOY-RFP-03) let the edge crew run the full 50-to-3000 wet sequence on the machine exact grit schedule instead of hand-faking a match at the end.

Frequently Asked Questions

Q: How long should I spend at each grit level when polishing concrete?

A: Roughly 2-3 overlapping passes per grit, or about 3-8 minutes per m2 depending on the stage and your machine. Rough stages (50-200 grit) take the longest; finishing stages (800-3000 grit) move fastest. Always finish by scratch pattern, not by clock.

Q: How do I know when to step up to the next grit?

A: Rinse and squeegee a test strip dry, then look at it from a grazing angle. If no scratches from the previous grit are visible, you are ready. If they show, keep the same grit for another pass or two.

Q: Can I skip a grit to save time on a small job?

A: Not on wet polishing. Skipping 200 or 400 grit saves about 10 minutes but almost always costs 30-60 minutes of correction at the 800-1500 stage, because the inherited scratch pattern will not polish out.

Q: Why does one grit take twice as long today as it did on the last job?

A: Most likely worn pads, harder concrete, or a machine losing weight or pressure on the head. Check pad freshness first - it is responsible for the majority of these surprises.

Q: Is wet polishing slower than dry polishing per grit?

A: Per pass, wet cutting is slightly slower, but it produces a cleaner scratch pattern and avoids burnishing mistakes, so the full 50-to-3000 sequence usually finishes in comparable time with a better final gloss.

Conclusion

Budget the grit sequence by passes and scratch patterns, not by minutes: 2-3 passes per level, 3-8 minutes per m2 on the rough stages and 1-3 minutes on the resin stages, stepping up only when the floor wipes clean of previous-grit marks. The crews who finish faster are not rushing grits - they are running fresh pads, consistent overlaps and the full sequence in order. If your current pad set keeps dragging the 800-3000 stages, compare the time saved with a matched resin polishing pad set (JOY-RFP-01) before you blame the machine or the floor.