A grit sequence is the planned progression from a coarser abrasive to finer grits. Each step should remove the scratch pattern from the step before it. Starting too fine wastes time; jumping too far leaves deep scratches that reappear after coating or polishing.
The basic progression
The first grit does the shaping, defect removal or stock removal. Every later grit exists mainly to replace the previous scratch pattern with a finer one. Stop when the surface meets the requirement of the next operation—not simply when you reach the highest grit available.
Avoid increasing the grit number by much more than about 50% in one step—for example, P80 to P120 or P120 to P180. This is a practical guide rather than a guarantee; hard surfaces, fine finishes and visible coatings may need smaller steps.
How to choose the starting grit
| Starting condition | Typical approach | Main risk |
|---|---|---|
| Heavy defects, welds or substantial stock removal | Start coarse enough to remove the defect efficiently | Deep scratches, heat or changing the workpiece geometry |
| Rough-sawn or uneven solid wood | Use a medium-coarse grit appropriate to the amount of levelling | Tear-out, cross-grain scratches or excessive material removal |
| Already smooth material | Start only as coarse as needed to create an even surface | Adding scratches that were not there before |
| Veneer or thin coating | Use a conservative starting grit and light, controlled sanding | Sanding through the face veneer or coating |
| Primer, paint or clear coat | Follow the coating manufacturer's process and test first | Breakthrough, visible scratches or adhesion problems |
Example grit sequences
These are starting examples, not fixed specifications. Adjust them for the initial surface, abrasive construction, machine, required finish and the coating or polishing system that follows.
Solid wood preparation
A rough surface might progress through P80 → P120 → P180. A cleaner machined surface may begin at P120. Some finishes require stopping earlier or later, so confirm the finish supplier's recommendation and test on the actual timber.
Panel and veneer sanding
Begin more conservatively than on thick solid wood. Use even pressure, confirm the remaining veneer thickness and avoid unnecessary coarse steps. Machine calibration and a consistent feed are as important as grit choice.
Metal blending and preparation
A sequence may move from stock removal to blending and then surface preparation—for example P60 → P80 → P120, followed by finer steps if the specified finish requires them. Stainless steel also demands heat control and suitable products that do not introduce unwanted contamination.
Primer and paint preparation
Use the abrasive and grit range specified by the paint system. The correct sequence differs for filler, primer surfacer, basecoat preparation and defect correction. Wet or dry use must match the abrasive construction and coating instructions.
Technique between grit changes
- Remove dust and loose coarse particles before changing to a finer grit.
- Inspect under good, angled lighting; do not rely only on how smooth the surface feels.
- Change sanding direction where the process allows it, making the previous scratch pattern easier to see.
- Let the abrasive cut. Excess pressure can create heat, deep scratches, loading and uneven removal.
- Replace a loaded or dull abrasive instead of compensating with more pressure.
- Keep the machine, extraction and contact surface consistent while comparing results.
Common grit-sequence problems
| Symptom | Likely sequence issue | What to check |
|---|---|---|
| Deep scratches remain after fine sanding | The jump between grits was too large, or coarse contamination remained | Return to the grit that can remove the defect, clean thoroughly, then progress again |
| Sanding takes too long | The starting grit may be too fine | Test one appropriately coarser grit without damaging the geometry or surface |
| Burning or discolouration | The abrasive may be dull, loaded or rubbing rather than cutting | Pressure, speed, extraction, abrasive condition and contact area |
| Uneven stain or coating appearance | The final scratch pattern may be inconsistent | Uniform sanding, grain direction, machine marks and finish compatibility |
Specify the whole sanding process
When asking for a recommendation, provide the material, starting condition, machine, abrasive dimensions, current sequence and required finish. Grain type matters too; see the abrasive grain selection guide, browse the featured products and data sheets, or share your process with Citra Oasis.