What Number Is Fine-Grit Sandpaper? | Shop Smart Guide

Before you grab a pack, a quick note on names. One label’s “fine” can be another label’s “very fine.” Don’t sweat wording. Go by the number on the back and the job you’re doing. The sections below break it down so you can pick the right sheet first time and sand with fewer steps.

Grit Names And Number Ranges

Here’s a fast mapping of common labels to the two numbering systems you’ll see in stores. Use this when a package says “fine” or “very fine” but you want the exact number.

What Number Is Fine Sandpaper For Wood Finishing?

For bare hardwoods, start around 120 or 150, then step to 180. Stop at 180 for clear oil finishes on open-pore species, or move to 220 when you’ll stain or spray film finishes. That keeps pores open enough for penetration while knocking down scratches from the prior pass.

On softwoods, a 120 → 180 → 220 progression keeps pitchy grain from tearing and gives a clean surface for stain. If you’re going straight to paint, stopping at 180 is common because the primer will fill fine marks and you’ll scuff again between coats.

Many pros group 220 with “very fine.” Others sell 220 as “fine.” Either way, the number does the work. A brand-neutral rule that never fails: don’t jump more than one step at a time. Move through consecutive steps so scratch depth shrinks in a controlled way.

What Number Is Fine-Grit Sand Paper For Paint Prep?

For scuffing existing paint before recoating, 180–220 does the trick. It keys the surface, dulls gloss, and avoids cutting through edges. For raw wood that will be painted, 120–180 is a safe finish point before primer. After primer dries, sand lightly with 220 to remove nibs and raise overall quality, then shoot the next coat.

Working on door frames or trim with decades of layers? Strip first or spot-feather with 120, then return to the fine range to unify the sheen. Over-sanding old paint with 80-grit leaves deep tracks that telegraph through topcoats.

CAMI Vs FEPA: Why Two Numbers?

CAMI prints a plain number like 150 or 220. FEPA adds a “P” in front—P180, P220, P240—and uses tighter particle tolerances on coated abrasives. The two scales aren’t identical, especially once you cross from macro to micro grits. That’s why you may see a small shift when you switch brands.

As a working map: CAMI 150 ≈ P150, CAMI 180 ≈ P180, CAMI 220 falls between P220 and P240. The particles at P180 average about the thickness of a human hair split into a few strips; P220 runs smaller again. Makers publish charts in microns if you want the exact sizes.

If a package mixes both systems, default to the “P” number when present. It’s the spec most coated-abrasive makers build to today, and it tends to be more consistent across vendors.

Fine Grit By Material And Task

Wood Furniture And Cabinets

For new builds, a 120 → 150 → 180 or 120 → 180 → 220 cadence is smooth and predictable. For refinishing, remove the old film with a coarser step first, then land in the fine range before you lay stain or a sealer coat. Between coats, use 320–400 light passes to knock down dust nibs without dulling corners.

Painted Surfaces

Use 180–220 to scuff glossy latex or alkyd. Wrap paper around a soft block near profiles and switch to hand pressure along edges to avoid burn-through. Vacuum dust before wiping so you don’t grind grit into the next coat.

Drywall And Joint Compound

Hit seams with 150–180 on a pole sander to level ridges, then touch up with 220 if the light still shows scuffs. Use a dust-extracting screen when you can. Keeping the grit in the fine band controls fuzzing of the paper face.

Metals And Plastics

Fine grits (180–220) deburr soft aluminum, brass, and mild steel and set up surfaces for primer. For acrylics and polycarbonate, start higher—often 320+—to avoid deep tracks; drop down only if molding marks demand it.

Pro Tips For Picking The Right Sheet

Choose The Mineral

Aluminum oxide is the everyday choice for wood and painted surfaces. Silicon carbide cuts fast on finishes and metal and works well for wet sanding. Ceramic blends show up more on belts and discs where long life matters.

Pick The Coat

Closed-coat papers pack the surface with grit and cut clean lines in hardwood. Open-coat leaves gaps between grains so dust can clear—handy on resinous pine, painted trim, and drywall.

Mind The Backing

Flexible A-weight sheets wrap profiles without cracking. Stiffer C and D backings stay flat on blocks and fair broad panels. For machines, match the hole pattern and hook-and-loop or PSA backing the tool expects.

Work A Clean Progression

Run the sander just long enough to remove the previous scratches, not to polish. Wipe or vacuum between steps so stray grains don’t scratch up your next pass. A quick raking light across the surface will tell you if you’re ready to move on.

Grit Progressions That Work

Here are simple step plans that land in the fine-grit window without wasting sheets or time.

Reading Packaging Without Guesswork

Look for three clues: the number, any “P” prefix, and the task icon. If you only see a label like “fine,” flip the sheet and read the number printed on the back. When you see both 220 and the word “fine,” treat it as a fine-range sheet even if another brand calls 220 “very fine.” The grit number rules.

Some packs bundle multiple steps—say 120, 150, 220. Use them in order. Resist the urge to skip directly to 220 from 120; you’ll chase hidden 120 lines for much longer than a quick pass at 150 or 180 would take.

Troubleshooting Swirls And Gloss Dull Spots

Swirls Won’t Disappear

If you can still see curly marks after stepping up, you moved on too early. Drop back one step, sand until the old pattern is gone, then climb again. Keep the pad flat. Tilting digs trenches that even 320 won’t hide.

Blotchy Stain Take-Up

If stain grabs darker patches, you may have closed the surface too much in spots or skipped a step. Re-sand that area at 180, wipe clean, and re-apply a light coat. A sanding sealer can even out tricky woods before color.

Edge Burn-Throughs

On profiles and corners, hand sand with the sheet folded to support the edge. Let the paper ride the shape instead of pressing the power sander into high spots.

When To Stop At 180 Vs 220

Stop at 180 when you want strong finish bite on open-pore woods with oil or wiping varnish. Go to 220 when you’ll stain, spray lacquer, or lay water-based topcoats that accent scratch patterns. For paint, both land well: 180 before primer, 220 between coats.

If you sand beyond 220 on bare wood, you can polish the surface so much that thin stains struggle to wet the fibers. That’s helpful on blotch-prone species if you’re aiming for a natural look, but it can fight you when you want even color.

Quick Buy List

Grab a mixed pack with 120, 150, 180, and 220. Add a small stack of 320 for between coats. Choose aluminum oxide for wood and paint, silicon carbide for wet work and metals, and keep both open- and closed-coat sheets on hand. Toss worn sheets early; fresh paper cuts cooler, faster, and cleaner.

Hand Vs Machine With Fine Grits

Random-orbit sanders shine in the fine range. Let the pad float and keep it moving; pressing down stalls the orbit and digs rings. Overlap passes evenly and lift off while the pad spins so you don’t stamp a stop mark. Stay steady.

Hand sanding wins at edges, profiles, and end grain. A cork or rubber block keeps faces flat. Fold the sheet into thirds and rotate to a fresh face as it dulls.

Dust, Loading, And Longer Sheet Life

Fine particles clog quickly. Knock dust out often with a crepe block. Stearated “no-fill” papers resist loading on paint and resinous woods, and open-coat papers clear chips faster.

If your sander accepts a hose, use dust extraction. It keeps grit from recirculating and lowers heat. For wet work on finishes and metals, silicon-carbide sheets in water or mineral spirits shed swarf and leave a crisp, level scratch.

Fine Grit Myths You Can Skip

“Higher Is Always Better”

Bare wood often tops out at 180–220. Pushing higher can seal the surface and reduce even color take-up. Save 320+ for between-coat leveling.

“One Heavy Pass Beats Several Light Passes”

Heavy pressure crushes fibers and leaves uneven tracks. Light sweeps with clean paper are faster in the end.

“Cross-Grain Fixes Everything”

Use cross-grain only for flattening. Finish with the grain so lines don’t flash under dyes and water-based topcoats.

Scratch Sizes In Real Numbers

Grit numbers tie back to particle size. In the FEPA spec, P180 centers near 82 microns and P220 around 68 microns. That single step shrinks scratch depth enough that finish hides it easily. Pad softness and speed change how those lines read, so test on scrap before you commit.

Mini Glossary For Faster Picks

CAMI: US numbering for coated abrasives; plain numbers like 150 or 220.

FEPA P-grade: European numbering; a “P” prefix like P180 or P220, based on microns.

Open-coat: Gaps between grains so dust escapes; handy on paint, pine, drywall.

Closed-coat: Near-full grain coverage for crisp, flat tracks on hardwoods.

Stearate: Anti-clog coating that keeps fine papers cutting on paint and soft finishes.

Scuff sanding: Light pass that dulls gloss and improves adhesion between coats.

Safety And Setup For Fine Grits

Fine dust hangs in the air longer. Wear eye protection and a dust mask or a respirator rated for fine particulates. Clamp workpieces so the sander doesn’t skate, and clear the bench so sheets don’t pick up stray grit. Set a raking light across the surface; those low shadows reveal scratches you’d miss under ceiling lights. Always test your full grit sequence on a scrap offcut from the same batch so your finish and color match what you’ll see on the real part. Keep a small magnet handy to lift stray steel filings after drilling or grinding.

Want the specs behind the numbers? See Norton’s sanding guide for how makers label fine and very fine, check FEPA microns on the FEPA P-grade chart, and read a quick primer on systems with Klingspor’s FEPA vs CAMI page.