Sanding Disc Grit Guide: From 40 to 800 — What Each Grit Is Used For

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Sanding Disc Grit Guide: From 40 to 800 — What Each Grit Is Used For

Sanding Disc Grit Guide: From 40 to 800 — What Each Grit Is Used For

Grit number is the single most important spec on a sanding disc. It tells you how coarse or fine the abrasive is — and choosing the wrong grit means either tearing up a surface that needed gentle treatment, or wasting time with a fine grit that can't cut fast enough for the job.

This guide covers every common grit from 40 to 800, explains what each is used for, and helps you build the right grit selection for your work.

How Grit Numbers Work

Grit number refers to the number of abrasive particles per square inch — the higher the number, the finer the abrasive and the smaller the scratches it leaves. Lower numbers cut faster and more aggressively; higher numbers produce smoother finishes.

  • Coarse (36–80 grit): Fast material removal, leaves deep scratches
  • Medium (100–180 grit): General sanding, surface prep, scratch refinement
  • Fine (220–320 grit): Finish sanding, primer sanding, light stock removal
  • Very Fine (400–800 grit): Final finishing, wet sanding, polish prep

Grit-by-Grit Breakdown

40 Grit — Extra Coarse

Use for: Aggressive paint stripping, heavy rust removal, rapid shaping of body filler, removing thick coatings.

40 grit cuts extremely fast and leaves deep scratches. It should only be used where maximum material removal is needed and the surface will be refined through multiple subsequent grits. Not suitable as a final step before any coating.

60 Grit — Coarse

Use for: Paint stripping, rust removal, rough shaping of body filler, initial stock removal on wood.

Slightly less aggressive than 40, but still a heavy-duty cutting grit. Common as a starting point for automotive paint removal and filler shaping.

80 Grit — Coarse

Use for: Final filler shaping, feathering paint edges, scuffing bare metal for primer adhesion, rough wood dimensioning.

80 grit is one of the most-used grits in auto body work. It's the standard for final filler shaping before primer, and the minimum grit most primers require for adhesion. In woodworking, it's used for initial stock removal and dimensioning rough lumber.

100 Grit — Medium-Coarse

Use for: Smoothing 80-grit scratches, general wood sanding, removing mill marks from lumber.

A transitional grit that bridges coarse and medium work. Common in woodworking for initial smoothing after dimensioning.

120 Grit — Medium

Use for: Smoothing body filler after 80-grit shaping, scuffing metal for primer, general wood surface prep.

120 grit is a workhorse in both automotive and woodworking applications. In auto body, it refines 80-grit scratches before primer. In woodworking, it's often the starting grit for pre-finished surfaces.

150 Grit — Medium

Use for: Final surface prep before high-build primer, smoothing wood before stain or sealer.

150 grit leaves scratches fine enough for most primers to fill, while still cutting efficiently. A common final prep grit before spraying high-build primer in auto body work.

180 Grit — Medium-Fine

Use for: Leveling high-build primer, final wood sanding before finish coats, removing 150-grit scratches.

180 grit is the standard starting point for primer sanding in automotive refinishing. It levels primer texture efficiently without cutting so deep that the next grit has to work too hard.

220 Grit — Fine

Use for: General primer sanding, feathering repair edges, final wood sanding before clear finish, between-coat sanding on wood.

220 grit is one of the most versatile grits in any shop. In auto body, it's used for general primer sanding and blending. In woodworking, it's the standard final sanding grit before applying stain, oil, or clear finish.

240 Grit — Fine

Use for: Refining 220-grit scratches, light primer sanding, between-coat sanding on furniture.

A step between 220 and 320, useful when you want a finer scratch pattern before topcoat without jumping straight to 320.

320 Grit — Fine

Use for: Final primer sanding before sealer or basecoat, scuffing sealer coats, between-coat sanding on lacquer or varnish.

320 grit leaves a scratch pattern fine enough that most automotive topcoats will not telegraph through. It's the standard final sanding grit before applying basecoat in many refinishing systems.

400 Grit — Very Fine

Use for: Scuffing existing paint before blending, light clearcoat sanding, final prep before basecoat on blend panels.

400 grit is used for scuffing sound existing paint to promote adhesion before blending in new basecoat. Also used for light wet sanding of clearcoat runs or dust nibs.

600 Grit — Very Fine

Use for: Wet sanding clearcoat, removing heavy orange peel, sanding runs in clear.

600 grit is a common starting point for wet sanding fresh clearcoat. It removes significant texture and runs while leaving scratches that 800 or 1000 grit can refine before polishing.

800 Grit — Ultra Fine

Use for: Wet sanding clearcoat, leveling moderate orange peel, final sanding before machine polish.

800 grit leaves a very fine scratch pattern that a dual-action polisher with cutting compound can remove efficiently, producing a high-gloss finish. Many detailers and refinishers finish wet sanding at 800–1000 grit before moving to polish.

Grit Quick Reference Chart

Grit Category Primary Uses
40 Extra Coarse Paint stripping, heavy rust, rapid filler shaping
60 Coarse Paint removal, rust, rough filler shaping
80 Coarse Final filler shaping, feathering, primer adhesion prep
100 Medium-Coarse Smoothing 80-grit scratches, rough wood sanding
120 Medium Filler refinement, metal prep, general wood sanding
150 Medium Pre-primer prep, wood before stain
180 Medium-Fine Primer leveling, final wood sanding
220 Fine Primer sanding, final wood finish prep
240 Fine Between-coat sanding, refining 220 scratches
320 Fine Final primer sanding, pre-basecoat prep
400 Very Fine Scuffing existing paint, light clearcoat sanding
600 Very Fine Wet sanding clearcoat, removing runs
800 Ultra Fine Wet sanding before polish, orange peel removal

Shop Indasa Sanding Discs by Application

For Automotive Bodywork (All Grits)

For PSA / Production Use

Related Guides

Not sure which grit is right for your job? Contact us — we're happy to point you in the right direction.

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