How to Choose the Right Sanding Disc Grit
Posted by Kimberly Fontaine-Goodwin on
Why Grit Selection Matters
Choosing the wrong grit is the most common sanding mistake. Go too coarse and you'll leave deep scratches that take hours to sand out. Go too fine and you'll spend twice as long removing material. Getting grit selection right from the start saves time, abrasive, and frustration.
Grit numbers refer to the size of the abrasive particles on the disc. Lower numbers = larger particles = more aggressive cutting. Higher numbers = finer particles = smoother finish.
The Grit Scale at a Glance
- P40–P60 (Extra Coarse): Heavy stock removal, stripping old paint or coatings, shaping wood. Leaves deep scratches — always follow with finer grits.
- P80–P120 (Coarse): General material removal, leveling surfaces, removing mill marks. The workhorse range for most initial sanding passes.
- P150–P180 (Medium): Intermediate sanding, blending, and prep before finishing. Removes scratches left by coarser grits.
- P220–P320 (Fine): Final sanding before primer or stain. Produces a smooth surface ready for coating.
- P400–P600 (Very Fine): Sanding between coats of paint or finish. Scuffs the surface for adhesion without cutting through.
- P800–P2000+ (Ultra Fine): Wet sanding clear coats, lacquers, and automotive finishes. Used before polishing compounds.
Grit Progression: Don't Skip Steps
One of the most important rules in finishing is to follow a logical grit progression — typically jumping no more than one or two grit steps at a time. For example: P80 → P120 → P180 → P220. Skipping from P80 straight to P220 means the fine grit is trying to remove scratches it wasn't designed for, which wastes time and abrasive.
A good rule of thumb: each successive grit should remove the scratches left by the previous one before you move on.
Grit by Application
Woodworking
Start with P80–P100 for rough lumber or heavy shaping. Move through P120, P150, and P180 for furniture and cabinetry. Final hand-sanding at P220 before staining gives the cleanest results.
Automotive Body Work
Feathering edges and shaping body filler typically starts at P80–P120. Primer sanding is usually done at P180–P220. Sanding between clear coat layers calls for P400–P600, and final color sanding before polishing uses P1000–P2000 wet.
Metal Fabrication
Weld seam grinding starts at P40–P60. Blending and smoothing moves to P80–P120. Surface prep for painting typically finishes at P180–P220.
Paint and Finish Coats
Between-coat sanding at P320–P400 scuffs the surface for adhesion. For a glass-smooth final finish, wet sand at P800–P1500 and follow with a polishing compound.
Abrasive Mineral Matters Too
Grit number alone doesn't tell the whole story — the abrasive mineral affects cut rate, durability, and cost:
- Aluminum Oxide: The most common all-purpose abrasive. Good for wood, metal, and general use.
- Zirconium: Tougher and longer-lasting than aluminum oxide. Excellent for aggressive metal grinding and heavy stock removal.
- Silicon Carbide: Very hard and sharp. Ideal for wet sanding, finishing hard materials, and working with composites or glass.
- Ceramic: Premium abrasive with self-sharpening properties. Stays sharp longer and cuts faster — best for high-production work.
Shop Sanding Discs by Grit
Browse our full selection of sanding discs to find the right grit and mineral for your project:
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