How to Sand Aluminum for Painting and Polishing

Aluminum is lightweight and durable, but it requires proper sanding before painting or polishing. Without the right preparation, paint won’t adhere well, and polishing won’t achieve a mirror finish. Here’s the complete guide to sanding aluminum surfaces step by step.

Why Sand Aluminum?

Sanding removes oxidation, scratches, and surface irregularities. It also creates a texture for primer and paint to grip. For polishing, sanding progressively smooths the metal until it’s ready for buffing.

Tools You’ll Need

• 9x11 in wet/dry sandpaper sheets
• Sanding block or orbital sander
• Spray bottle with water
• Microfiber cloths
• Primer and paint or polishing compound

Best Grit Sequence for Aluminum

• 320 grit: Removes oxidation and surface roughness.
• 600 grit: Smooths scratches and prepares for primer.
• 1000 grit: Refines surface for basecoat or pre-polish.
• 1500 grit: Pre-polish sanding for semi-gloss finish.
• 2000 grit: Ultra-fine sanding before final polishing.

Step-by-Step: Sanding Aluminum

1. Clean the surface. Wash thoroughly to remove grease and dirt.
2. Start with 320 grit. Use 320 grit (25-pack) to strip oxidation and level roughness.
3. Smooth with 600 grit. Apply 600 grit (50-pack) to refine scratches.
4. Refine with 1000 grit. Use 1000 grit (100-pack) before priming or polishing.
5. Polish with 1500 grit. Wet sand for a smooth, semi-gloss surface.
6. Finish with 2000 grit. Ultra-fine sanding ensures a mirror-ready finish.
7. Clean thoroughly. Wipe with microfiber before applying primer or polish.

Special Cases

For heavily oxidized aluminum, you may start with 220 grit. For decorative aluminum pieces, stick to finer grits to avoid scratches.

Pro Tips

• Always wet sand aluminum to prevent clogging and heat buildup.
• Sand in alternating directions with each grit for consistent results.
• Use polishing compounds after 2000 grit for a true mirror finish.

Aftercare

• Apply clear coat or wax to protect aluminum surfaces.
• Clean with mild soap to avoid scratching.
• Re-polish as needed to maintain shine.

FAQs

• Do I need primer on aluminum before painting? Yes—self-etching primer ensures paint adhesion.
• Can I polish aluminum without sanding? No—sanding removes scratches and oxidation first.
• What grit before polishing? 1500–2000 grit provides the best pre-polish surface.

Watch & Learn

For aluminum prep, use eQualle’s wet/dry sandpaper sheets, available in 25, 50, and 100 packs. Shop aluminum sanding sheets here.