Choosing the right sandpaper grit is one of the most important steps in achieving a perfect finish. Whether you are working on wood, metal, plastic, or painted surfaces, using the correct grit helps you remove material efficiently, avoid scratches, and save time.
1. What Does Sandpaper Grit Mean?
Sandpaper grit refers to the size of the abrasive particles on the sandpaper's surface.
Low grit numbers = coarse and rough (remove material quickly)
High grit numbers = fine and smooth (used for finishing)
Common Grit Ranges:
| Grit Range | Type | Purpose |
| 60–80# | Coarse | Shaping, smoothing rough surfaces |
| 100–150# | Medium | General sanding before finishing |
| 180–220# | Fine | Final surface smoothing |
| 240–400# | Very Fine | Between coats of paint or varnish |
| 600–2000# | Ultra-Fine | Polishing, automotive finishing, metal shine |
2. Choosing Sandpaper Grit for Different Surfaces
A. Wood Surfaces
Wood is one of the most common materials for sanding.
The goal is to remove imperfections, smooth the grain, and prepare the surface for staining or painting.
Recommended Grits:
| Step | Grit Range | Purpose |
| Rough shaping | 40–60 # | Remove saw marks or uneven surfaces |
| Smoothing | 80–120# | Prepare raw wood for finish |
| Finish sanding | 150–220 # | Smooth before painting or staining |
| Between coats | 240–320# | Light sanding between varnish or paint layers |
B. Metal Surfaces
Sanding metal helps remove rust, old paint, or burrs, and prepares it for coating or welding.
Recommended Grits:
| Step | Grit Range | Purpose |
| Rust/paint removal | 40–80# | Coarse removal |
| Surface leveling | 100–150# | Smooth and prepare metal |
| Finishing & polishing | 240–600# | For a shiny or reflective finish |
Tip: Use aluminum oxide or zirconia abrasives for strong metals; silicon carbide for polishing or softer metals.
C. Automotive & Paintwork
When sanding car paint or body filler, it's important to choose the right grit to avoid damaging the surface.
Recommended Grits:
| Step | Grit Range | Purpose |
| Body filler shaping | 80–120# | Level the surface |
| Primer sanding | 180–320# | Smooth before paint |
| Paint leveling | 400–800# | Remove small imperfections |
| Final polishing | 1000–3000# | High-gloss finish or wet sanding |
Tip: For auto refinishing, wet/dry waterproof sandpaper works best.
D. Plastic and Composite Materials
Plastic and fiberglass can easily overheat or scratch, so always sand gently.
Recommended Grits:
| Step | Grit Range | Purpose |
| Initial shaping | 120–180# | Light material removal |
| Surface prep | 220–320 # | Smooth and uniform finish |
| Polishing | 400–800# | Final shine or coating prep |
E. Painted Surfaces
When sanding paint or varnish, the grit depends on whether you want to remove old paint or smooth new coatings.
Recommended Grits:
| Step | Grit Range | Purpose |
| Removing old paint | 40–80# | Strip old coatings quickly |
| Leveling primer | 120–180# | Smooth rough primer surfaces |
| Between paint coats | 240–400# | Light sanding for adhesion |
| Polishing | 600–2000# | Smooth glossy surfaces |
Tip: Use fine grit sanding sponge or waterproof sandpaper for a smooth finish.
Tip: Avoid pressing too hard - overheating can cause plastic to melt.
Selecting the right sandpaper grit depends on your surface type, desired finish, and work stage.
