How to Sand Aluminum for Painting & Polishing (150, 220, 400, 600 Grit Guide)

Aluminum is lightweight and durable, but its smooth surface makes painting and finishing tricky. Proper sanding improves adhesion for coatings and creates the perfect base for polishing. This guide explains how to sand aluminum step by step using the correct grit sequence.

Why Sanding Aluminum Matters

Aluminum naturally forms an oxide layer that resists coatings. Sanding removes oxidation, smooths imperfections, and gives paint or polish something to bond to. Without sanding, coatings may peel and polished finishes will look uneven.

Tools & Materials

• Wet/dry sandpaper sheets
• Sanding block or orbital sander
• Degreaser and microfiber cloths
• Polishing compound or primer
• Safety glasses and gloves

Best Grit Sequence for Aluminum

• 150 grit: Removing oxidation and surface roughness.
• 220 grit: Leveling and prepping for finer sanding.
• 400 grit: Refining for paint adhesion or pre-polish prep.
• 600 grit: Final sanding for a smooth, satin base.

Step-by-Step: Sanding Aluminum

1. Clean the surface. Remove grease and debris with a degreaser and cloth.
2. Start coarse. Use 150 grit (50-pack) to remove oxidation and scratches.
3. Smooth with 220 grit. Switch to 220 grit (100-pack) for an even surface.
4. Refine further. Use 400 grit (50-pack) for prepping aluminum for paint or polish.
5. Final sanding. Finish with 600 grit (25-pack) for a satin smooth result.
6. Clean again. Wipe with tack cloth before painting or polishing.

Special Cases

• Polishing aluminum: Continue sanding up to 1000–2000 grit before buffing.
• Painting aluminum: Apply self-etching primer after 400–600 grit sanding.
• Thin sheets: Avoid aggressive sanding to prevent distortion.

Pro Tips

• Always wet sand finer grits to reduce clogging and scratches.
• Sand in straight lines, alternating direction with each grit.
• Use light pressure—aluminum is softer than steel and scratches easily.
• Polish immediately after final sanding to prevent oxidation.

Aftercare

• Seal polished aluminum with wax or clear coat to prevent oxidation.
• For painted aluminum, reapply protective coats as needed.
• Store sanded aluminum indoors until finishing to avoid re-oxidation.

FAQs

• Can I paint aluminum without sanding? No, paint will not adhere properly without surface prep.
• What grit before polishing? At least 600 grit, ideally up to 2000 grit for mirror polish.
• Is aluminum harder to sand than steel? No, aluminum is softer—use less pressure to avoid gouges.

Watch & Learn

Sanding aluminum properly ensures long-lasting finishes, whether painting or polishing. Stock up on 150 to 600 grit sandpaper sheets for aluminum projects. Explore the full metal sanding sandpaper collection today.