Auto body repair places high demands on abrasive material. The paint build-up is thin, the substrate is expensive and mistakes are hard to reverse. This is the standard sequence in practice.
Rust removal and sheet metal (P40–P80)
For coarse material removal on bare steel. Run on power sanders with ceramic or zirconium grain for maximum lifespan. After sanding, prime immediately to prevent re-oxidation.
Filling and filler work (P80–P150)
Filler is applied and flat-sanded after curing. Start with P80 for coarse profiling, work up to P150 for the finish. Use long sanding blocks on large surfaces to avoid wave formation.
Primer (P180–P320)
Primer is interlayer-sanded at P220–P320 for an even adhesion profile. Watch edges and corners: paper wears faster here and you’ll cut through sooner. Use a softer block in these areas.
Interlayer-sanding the topcoat (P400–P500)
After the first topcoat, sand out dust nibs and texture defects at P400–P500. Always dry, always inspect under raking light before applying the next coat.
Wet sanding and polishing (P800–P2000)
Wet-sand the finished topcoat for orange peel, overspray and minor irregularities. Work up to P2000 and then use a polishing machine and compound to bring out the final gloss.