How to Sand Aluminum for Painting & Polishing (80, 150, 220, 320 Grit Guide)

Aluminum is lightweight, strong, and widely used in projects from auto parts to furniture. But its slick surface doesn’t hold paint or polish well without preparation. Sanding aluminum creates the proper texture for adhesion and removes oxidation for a mirror-like shine. This guide explains how to sand aluminum step by step using 80, 150, 220, and 320 grit sandpaper.

Why Sanding Aluminum Matters

Raw aluminum oxidizes quickly, forming a dull layer that weakens paint adhesion. Sanding removes oxidation, smooths the surface, and provides the perfect foundation for coatings or polishing. Skipping this step often leads to peeling paint or uneven finishes.

Tools You’ll Need

• 80–320 grit sandpaper – coarse to medium for aluminum prep.
• Sanding block or orbital sander – ensures even results.
• Water spray bottle – for wet sanding with finer grits.
• Polishing compound – for a glossy finish.
• Microfiber cloth – removes dust and slurry between stages.

Best Grit Sequence for Aluminum

• 80 grit: Removes heavy oxidation, scratches, and old coatings.
• 150 grit: Refines coarse scratches from initial sanding.
• 220 grit: Prepares aluminum for paint or primer.
• 320 grit: Creates a smooth, even finish for polishing or final coats.

Step-by-Step Sanding Process

1. Start with 80 grit. Strip oxidation and tough coatings using 80 grit (50-pack).
2. Move to 150 grit. Smooth and refine the surface with 150 grit (25-pack).
3. Refine with 220 grit. Prepare for primer or paint using 220 grit (100-pack).
4. Finish with 320 grit. Wet sand for a smooth, satin-like surface. Try 320 grit (25-pack).
5. Optional polish. Apply compound with a buffing pad for a mirror finish.

Special Cases

For thin aluminum sheets, avoid aggressive sanding—start at 150 grit. For auto body parts, finish with 320 grit before primer. To restore decorative pieces, continue beyond 320 grit up to 1000–3000 grit before polishing.

Pro Tips

• Always wet sand finer grits to reduce scratches and heat buildup.
• Sand in straight, consistent strokes to maintain a uniform look.
• Seal freshly sanded aluminum with paint, clear coat, or wax to slow oxidation.
• Replace sandpaper often—aluminum clogs sheets quickly.

Aftercare

• Wipe aluminum clean with microfiber after sanding.
• Apply primer or polish immediately to prevent re-oxidation.
• Re-polish periodically if left uncoated for shine maintenance.

FAQs

• Can I sand aluminum with steel wool? Not recommended—it leaves steel particles that rust.
• Do I need to sand aluminum before painting? Yes—sanding improves adhesion dramatically.
• Will aluminum rust if not coated? No, but it oxidizes, leaving a dull surface.

Watch & Learn

For the best results on aluminum surfaces, explore our metal sanding sandpaper collection.