Polishing Aluminum Parts for a Mirror Shine (400, 800, 1200, 2000 Grit Guide)

From motorcycle rims to engine covers, aluminum parts can lose their luster over time. With the right sanding and polishing sequence, you can restore aluminum to a brilliant, mirror-like shine that rivals chrome. This process requires patience and progressively finer sandpaper grits.

Why Sand Aluminum?

Raw aluminum scratches easily and oxidizes, leaving a dull, matte appearance. Sanding removes oxidation, smooths the surface, and prepares it for polishing compounds that bring out a reflective finish.

Tools You’ll Need

• Wet/dry sandpaper sheets
• Foam sanding block
• Microfiber cloths
• Water spray bottle
• Aluminum polishing compound

Best Grit Sequence for Aluminum Polishing

• 400 grit (50-pack) — Removes oxidation and initial scratches.
• 800 grit (50-pack) — Smooths the surface for intermediate refinement.
• 1200 grit (25-pack) — Prepares aluminum for high-gloss polishing.
• 2000 grit (50-pack) — Final ultra-fine sanding before compound polishing.

Step-by-Step: Sanding Aluminum

1. Clean the part. Remove grease and dirt with a degreaser before sanding.
2. Start with 400 grit. Use 400 grit sandpaper with water to strip oxidation and scratches.
3. Smooth with 800 grit. Switch to 800 grit sheets to refine the surface.
4. Refine with 1200 grit. Sand with 1200 grit sheets to bring aluminum close to a satin finish.
5. Finish with 2000 grit. Apply 2000 grit sandpaper for a glass-smooth surface.
6. Polish with compound. Use an aluminum polish to achieve a mirror-like shine.

Special Cases

• Heavily oxidized aluminum: May require more time at 400 grit.
• Thin aluminum parts: Use light pressure to avoid warping.
• Automotive trim: Finish with 2000 grit for the deepest reflection.

Pro Tips

• Always wet sand to prevent clogging and heat buildup.
• Sand in alternating directions with each grit for uniform results.
• Buff with a microfiber cloth after polishing for extra brilliance.

Aftercare

• Seal polished aluminum with wax or a clear coat to slow oxidation.
• Clean regularly with non-abrasive products.
• Re-polish occasionally to maintain shine.

FAQs

• Can I machine polish aluminum? Yes, but sanding is essential first for a smooth base.
• Does aluminum rust? No, but it oxidizes—sanding and sealing prevent dullness.
• Can I skip to 2000 grit? No, each grit stage builds on the last for best results.

Watch & Learn

With the right sanding sequence, aluminum parts can shine like chrome. Stock up on metal sanding sheets and restore your projects to a mirror finish.