Quick Answer

A 100-grit pad cuts aggressively and removes material, while a 400-grit pad refines scratches and prepares the surface for gloss. Use 100 grit early in the resin phase to remove metal-bond scratches and level the surface; use 400 grit after 100-200 grit to smooth the pattern before moving to 800 and above.

What Grit Number Means for the Pad

The grit number refers to the diamond particle size: lower numbers use larger diamonds that cut fast and leave deeper scratches; higher numbers use finer diamonds that cut slowly and leave a smoother surface. A 100-grit pad removes roughly ten times the material of a 400-grit pad per pass, but leaves a scratch pattern that 400 then removes. This is why pads are used in order, not interchangeably.

When to Use 100 Grit

Use 100 grit when the floor needs the resin phase to do real work: removing remaining metal-bond scratches, flattening light surface irregularities, or stripping a light sealer. It is also the correct first resin grit when the metal phase ended at 80 or 120. Run 100 grit with firm feed and check under raking light that the coarse pattern is uniform before advancing.

When to Use 400 Grit

Use 400 grit after 100-200 grit to refine the surface and prepare for the gloss passes. It removes the 100-grit scratches and leaves a fine, uniform pattern that 800-1500 will turn into a shine. 400 is also a useful maintenance grit: re-polishing a lightly worn floor with 400, 800, 1500 restores gloss without a full sequence.

Building the Full Sequence Around Them

The standard resin sequence around these two steps is 100 → 200 → 400 → 800 → 1500 → 3000. Some floors can skip 100 and start at 200, but 400 should never come before 100 or 200. If you are unsure where to start, run 200 first and inspect: if it cuts visibly, you were fine starting there; if it loads or polishes without cutting, drop to 100.

Frequently Asked Questions

Q: Can I skip 100 grit and start at 400?

A> Only if the metal phase ended at 200 and the floor is clean. Otherwise 400 will glaze trying to remove deep scratches.

Q: Which pad wears out faster, 100 or 400?

A> 100 grit wears faster because it cuts harder and removes more material. Fine pads last longer when the floor is clean.

Q: Do I need both for a maintenance re-polish?

A> For light maintenance, 400 is enough if the floor is only dull. For visible scratches, use 100 first, then 400.

Conclusion

100 and 400 grit pads are partners, not rivals: 100 removes and levels, 400 refines and prepares. Use them in the right order and the resin phase flows cleanly into the gloss steps.