Using Aluminum Oxide Discs on Metal: Grit Guide
By Supergrit Abrasives | Published: 2026-10-18
Category: How-to Guides
Learn how to choose the right aluminum oxide disc grit for metal sanding, with step-by-step guidance and product recommendations from Supergrit Abrasives.
Quick answer
For general metal sanding, start with a coarse grit like 60 or 80 on an aluminum oxide disc, then progress to finer grits for a smooth finish. The 4-inch 80129 disc from Supergrit Abrasives is a reliable choice for these tasks.
Why grit sequence matters on metal
Metal surfaces require a specific grit progression to avoid uneven scratches or excessive material removal. Aluminum oxide discs are durable and work well on metals like steel, aluminum, and brass, but using the wrong grit can waste time or damage the workpiece.
The 4-inch aluminum oxide disc (product 80129) is a common size for handheld sanders and die grinders. Its compact diameter makes it easy to control on curved or small metal parts.
Step-by-step grit guide for metal sanding
- Start with coarse grit (60 or 80) for heavy material removal: Attach a 60 or 80 grit aluminum oxide disc to your sander. Use it to remove rust, paint, or weld splatter. Move the sander in straight lines to avoid gouging. Do not skip grits—jumping from 80 to 220 can leave deep scratches that are hard to remove.
- Switch to medium grit (120 or 150) for blending scratches: Replace the disc with a 120 or 150 grit. Sand over the entire surface using overlapping passes to blend the coarse scratches into a uniform finish. Check your progress under good light; visible scratches mean you need more passes at this grit.
- Finish with fine grit (220 or 320) for a smooth surface: Use a 220 or 320 grit disc for final smoothing. This step prepares the metal for painting or clear coating. Light pressure is key—let the disc do the work. If you see swirl marks, reduce sander speed or switch to a fresh disc to prevent loading.
Product facts
- 4" DIAM X 1/4" THICK X 5/8" ALUMINUM (GERMAN) 80129: This 4-inch disc is made of aluminum oxide and is offered in pack sizes of 10 or 25, giving you flexibility for project scale. Choosing the pack of 25 saves per-disc cost if you frequently sand metal, while the pack of 10 is ideal for occasional use.
4" DIAM X 1/4" THICK X 5/8" ALUMINUM (GERMAN) 80129
