Automotive Primer Sanding: 320–600 Grit Sandpaper Sheets

Before applying basecoat or paint, primer must be sanded smooth to ensure flawless adhesion. Using 9x11 inch sandpaper sheets in the correct grits makes primer sanding faster and more consistent. eQualle’s wet dry silicon carbide sandpaper sheets are engineered for automotive refinishing and bodywork prep.

Why Sand Primer?

Primer fills scratches and minor imperfections, but its surface is porous and uneven. Sanding levels the primer, smooths filler areas, and prepares the surface for basecoat. Skipping this step can cause poor adhesion, visible scratches, or peeling paint.

Tools You’ll Need

• eQualle metal sanding sandpaper sheets
• Sanding block or orbital sander with interface pad
• Clean water and spray bottle for wet sanding
• Microfiber cloths
• Automotive primer and basecoat

Best Grits for Primer Sanding

• 320 grit — Initial leveling of primer. 320 Grit (25-pack).
• 400 grit — Smooths primer for uniform surface. 400 Grit (25-pack).
• 600 grit — Final prep before basecoat. 600 Grit (50-pack).

Step-by-Step Primer Sanding

1. Begin with 320 grit sandpaper sheets. Sand the primed surface evenly to remove high spots and imperfections.
2. Switch to 400 grit. Wet sand with overlapping strokes to refine the primer surface.
3. Finish with 600 grit sandpaper sheets. Lightly wet sand until the primer is uniformly smooth and ready for paint.

Special Cases

For high-build primer, start with 220 grit to knock down thick coats before moving into the 320–600 grit sequence. For spot repairs, sanding with 600 grit only may be enough before blending.

Pro Tips

• Always wet sand above 400 grit to control dust and heat.
• Use guide coat spray to highlight low and high spots before sanding.
• Replace sheets as soon as they lose cutting power for consistent results.

Aftercare

• Wipe surfaces with microfiber cloths before basecoat.
• Store leftover sheets flat and organized by grit.
• Keep assorted grit packs handy for future touch-ups.

FAQs

• Can I paint directly over unsanded primer? Not recommended—painting over rough primer can lead to adhesion failure.
• What grit is best for primer before paint? 400–600 grit gives the smoothest results.
• Which pack is most useful? A 600 Grit (50-pack) is the go-to for final prep.

Watch & Learn

Get professional auto paint results with eQualle 9x11 in sandpaper sheets. Shop more options in the Metal Sanding Collection.