How to Sand Plastic Models for Painting (320, 400, 600, 800 Grit Guide)

Plastic model kits often have mold lines, sprue marks, or rough edges that show through paint if not sanded properly. Sanding is the key to achieving a professional, realistic finish on scale models. With the right grit sequence, you can smooth surfaces without scratching the plastic. This guide explains how to sand plastic models step by step using 320, 400, 600, and 800 grit sandpaper.

Why Sanding Models Matters

Even high-quality model kits leave imperfections after trimming sprues or gluing. Sanding blends seams, removes rough spots, and prepares the plastic for primer. Without sanding, small flaws become visible after paint, ruining realism.

Tools You’ll Need

• 320–800 grit wet/dry sandpaper – ideal for smoothing plastic without damage.
• Sanding sticks or files – for detail work on seams and joints.
• Water spray bottle – prevents heat buildup and scratches.
• Primer for plastic models – reveals imperfections after sanding.
• Microfiber cloth – cleans between steps.

Best Grit Sequence for Plastic Models

• 320 grit: Removes sprue marks, seams, and glue residue.
• 400 grit: Smooths scratches and levels surfaces.
• 600 grit: Refines for primer and paint adhesion.
• 800 grit: Final sanding for a satin-smooth finish.

Step-by-Step Model Sanding

1. Start with 320 grit. Remove seams and sprue marks using 320 grit (25-pack).
2. Smooth with 400 grit. Even out surfaces using 400 grit (100-pack).
3. Refine with 600 grit. Lightly wet sand with 600 grit (50-pack) before priming.
4. Finish with 800 grit. Use 800 grit (25-pack) for a silky, paint-ready surface.
5. Prime and inspect. Apply primer to check for flaws, then lightly re-sand if needed.

Special Cases

For clear plastic parts like canopies, never sand below 600 grit—start finer to avoid scratches. For resin kits, sanding dust can be hazardous, so always wear a respirator. Some small parts may benefit from sanding sponges for better control.

Pro Tips

• Sand in small strokes with light pressure—plastic is soft.
• Always wet sand finer grits for smooth results.
• Replace worn sheets frequently—dull paper scratches instead of smoothing.
• Use primer to reveal imperfections you may have missed.

Aftercare

• Handle models carefully after sanding to avoid oils from hands sticking before primer.
• Store sandpaper flat in a dry place to keep sheets usable.
• Re-sand lightly after priming if needed before painting.

FAQs

• Do I need to sand all model parts? Only visible areas or spots with imperfections need sanding.
• What grit should I use before primer? 600 grit works best for primer adhesion.
• Can sanding fix glue smudges? Yes—start at 320 grit, then refine up to 800 grit.

Watch & Learn

For flawless plastic model prep, shop our fine grit sandpaper collection.