What grit sandpaper after primer?

Primer serves as the critical bridge between a substrate and its topcoat, creating adhesion and hiding surface imperfections.

The ideal grit range for sanding primer depends on two core factors: the primer type and the desired smoothness of the final surface. For most DIY and professional projects, 220–320 grit sandpaper is the sweet spot. This range balances two essential goals: removing primer runs, dust nibs, or uneven application without scratching the surface deeply enough to show through the topcoat.

Lightweight primers, such as those used on automotive or furniture touch-ups, pair best with 320-grit sandpaper. This fine grit delivers a ultra-smooth base, ideal for high-gloss topcoats where even tiny scratches will stand out. For heavier primers, like latex-based formulas for walls or woodwork, 220-grit sandpaper works efficiently to level texture and eliminate brush marks without excessive effort. Avoid coarser grits (180 or below) after primer—they leave deep scratches that topcoats cannot conceal, ruining the final finish.

For specialty projects, adjust the grit accordingly. When prepping surfaces for enamel or lacquer topcoats, step up to 400-grit sandpaper for a glass-like base. For porous substrates like raw wood, a 220-grit initial sand after primer can be followed by a 320-grit final pass to ensure maximum topcoat adhesion.

Always follow these sanding best practices after primer application: work in a well-lit area to spot imperfections easily; use a sanding block or orbital sander for consistent pressure; and sand in the direction of the wood grain (for wood surfaces) to minimize visible scratch lines. After sanding, wipe the surface thoroughly with a tack cloth to remove all primer dust—any residue left behind will create bumps in the topcoat.

Stick to 220–320 grit sandpaper for most primer-sanding tasks, and tailor up or down based on your topcoat and substrate.