Sanding Between Coats of Varnish: Glass-Smooth Wood Finishes

Varnish protects wood while enhancing its natural beauty, but applying it without sanding between coats often leaves dust nibs, bubbles, or uneven layers. Light sanding ensures each coat bonds smoothly, creating a flawless, durable finish. This guide covers the grit sequence and process for sanding between varnish coats.

Why Sand Between Varnish Coats?

Each varnish layer can trap imperfections. Sanding levels the surface, dulls the sheen for adhesion, and ensures the final coat looks professional. Without sanding, the finish may peel, feel rough, or show visible brush strokes.

Tools You’ll Need

• Wet/dry sandpaper sheets (220–400 grit)
• Sanding block or foam pad
• Tack cloth or vacuum
• High-quality varnish brush
• Protective mask and gloves

Recommended Grit Sequence

• 220 grit: First sanding after the base coat dries.
• 320 grit: Smooth mid-coats before recoating.
• 400 grit: Final sanding for silky smooth topcoat.

Step-by-Step: Sanding Between Varnish Coats

1. Apply the first coat. Brush evenly along the grain and let dry fully.
2. Sand lightly with 220 grit. Use 220 grit (25-pack) to remove raised grain.
3. Clean the surface. Vacuum and wipe with a tack cloth.
4. Apply the second coat. Lay varnish smoothly with a brush.
5. Smooth with 320 grit. Use 320 grit (50-pack) once fully cured.
6. Sand with 400 grit. Use 400 grit (100-pack) before the final coat for a silky finish.
7. Apply topcoat. Leave untouched until fully cured for maximum durability.

Special Cases

For water-based varnishes, sanding is even more important since they raise the grain more than oil-based options. Avoid sanding too aggressively, which can cut through thin layers.

Pro Tips

• Sand lightly—just dull the shine, don’t remove the coat.
• Always sand with the grain to avoid scratches.
• Use fresh sandpaper for each stage for consistent results.

Aftercare

• Allow the final coat to cure for up to 7 days before heavy use.
• Dust regularly with a soft cloth to maintain the finish.
• Reapply varnish every few years to protect high-use surfaces.

FAQs

• Can I skip sanding between coats? Not recommended—sanding improves adhesion and smoothness.
• Do I need to wet sand? Dry sanding works well—wet sanding is optional for ultra-fine finishing.
• What grit before the last coat? 400 grit is ideal for a silky smooth top layer.

Watch & Learn

Sanding between varnish coats is the secret to flawless, glass-smooth wood finishes. Stock up on wet/dry sandpaper sheets—packs of 25, 50, and 100 available in all grits. Shop varnish sanding sheets here.