What grit should I sand for Awlgrip 545 and before the topcoat

Long answer

1. Before primer (545): Block and finish sand to 180 grit so the primer has consistent tooth and builds smoothly.
2. After 545 primer: Once cured per the TDS, sand the primed surface to 320–400 grit to promote adhesion and lay down a smooth base for the topcoat.
3. Between color coats: Lightly scuff with 320–400 grit as needed to remove nibs/defects and improve intercoat adhesion.
4. Surface prep: After sanding, vacuum, solvent-wipe (per system guidance), and tack rag before applying the next coat.
5. Break-throughs: If you sand through the primer, spot-reprime and allow proper cure before proceeding.