Proper Grit Jumps: Why 80?120?180 Beats Skipping

Skipping grits feels faster—until you spend twice as long chasing scratches that won’t disappear. The key to efficient, pro-level sanding is choosing proper grit jumps that reduce scratch depth in controlled steps. In practice, that means sequences like 80?120?180 (and sometimes 220) rather than jumping straight from 80 to 180. This guide explains the why, the when, and the exact steps to get a flatter, cleaner surface with fewer swirls and less work.

Why Grit Jumps Matter

Each grit leaves a predictable scratch depth and pattern. If you jump too far, the next grit can’t fully erase the deeper valleys, leaving ghost scratches that telegraph through stain or clear coat. Balanced steps keep the scratch pattern shallowing gradually so every pass removes the previous one’s marks without over-sanding. You’ll get:

• Faster total time because you’re not stuck polishing deep 80-grit valleys with too-fine paper.
• Flatter surfaces thanks to even material removal rather than localized rubbing.
• Cleaner finishes with fewer swirls, halos, or witness lines under raking light.

Tools & Materials

• Random-orbit sander with appropriate pad (firm for flatness, soft/interface for curves)
• 9×11 in silicon carbide wet/dry sheets (80–220+), sanding block, and foam pad
• Pencil for crosshatch guide coat, raking light, vacuum, and tack cloth
• Hearing, eye, and dust PPE (P100 for fine dust; use extraction where possible)

Recommended Grit Sequence

• 80 grit — Level defects quickly (mill marks, glue squeeze-out, rough epoxy edges).
• 120 grit — Removes 80’s trench marks efficiently without over-polishing.
• 180 grit — Refines for most film finishes and many stains.
• Optional 220 grit — For ultra-clear topcoats or blotch-prone species before dye.

Step-by-Step: The 80?120?180 Method

1. Map the surface. Lightly pencil a crosshatch across the workpiece. This simple guide coat reveals low spots and tells you when each grit has fully cut the surface.
2. Flatten and cut with 80. Sand diagonally, then with the grain to level high spots, remove planer tracks, or knock down epoxy ridges. Keep the sander moving, overlap passes, and avoid tipping at edges. For reliable stock removal on rougher surfaces, start with a quality 80-grit sheet like 80 grit (25-pack).
3. Erase 80’s scratches with 120. Re-mark a light guide coat. Your goal is to remove every last 80-grit line. The jump from 80?120 is big enough to refine, small enough to fully erase. Step up to 120 grit (50-pack) and sand until all 80-grit pencil and scratch marks are gone under raking light.
4. Refine to finish with 180. Add a fresh guide coat and sand just until uniform. This pass sets a tight, shallow scratch profile that finishes and stains love. For larger projects where consistency matters, stock 180 grit (100-pack).
5. (Optional) Kiss with 220. On dark dyes, high-gloss clears, or blotch-prone woods (maple, cherry), a brief 220 pass can reduce micro-scratch telegraph. Don’t burnish: stop as soon as the surface looks uniformly matte.
6. Vac, tack, and inspect. Vacuum dust from pores and edges, then tack. Use raking light: if any coarse lines remain, backtrack one grit and finish the area properly.

Why Not 80?180?

Jumping from 80 straight to 180 seems to save a step, but 180 struggles to remove 80’s deep, wide scratches. You’ll spend more time, load more paper, and may leave ghost scratches that appear only after stain or clear. The 80?120?180 ladder removes material in controlled layers—fewer surprises, cleaner results.

Special Cases & Material Notes

Softwoods (pine, cedar): Keep pressure light and papers fresh; softer fibers crush easily and show swirl. Consider 100?150?180 if starting surfaces aren’t rough.
Hard maple/cherry: Prone to burnish and blotch. Don’t linger; consider that optional 220 pass, and test finish on a sample.
Open-pore woods (oak, ash): 180 often yields great clarity. Going finer can reduce stain uptake; test first if you plan to dye.
Veneer: Know your thickness. If you start at 120 (to protect veneer), your sequence may be 120?150?180 with very light pressure.
Epoxy/Resin work: After leveling at 80, step 120?180 before moving to 220–400 (and eventually wet-sanding for polish).

Pro Tips

• Time-on-grit discipline: Don’t advance until the current grit’s scratches are 100% gone. Half-done work snowballs into extra time later.
• Pencil and light: A faint pencil map plus raking light is the cheapest, most effective QC system you can run.
• Interface pads: Use a soft interface on curves to prevent pigtails; use a firm pad for flat panels to preserve dead-flat geometry.
• Vacuum extraction: Dust between pad and surface acts like rogue grit. Good CFM reduces swirls and keeps cut rates high.
• Sand with the grain to finish: Even with RO, a final with-grain pass helps hide the pattern on stain-grade pieces.
• Paper lifecycle: Retire sheets early. Dull paper polishes instead of cutting, which looks smooth but leaves deeper scratches underneath.

Aftercare

• Before finishing, wipe with the solvent or cleaner recommended for your finish system (avoid silicone polishes).
• For waterborne clears, expect a slight grain raise; plan a light de-nib with 220 after the first sealer coat.
• Label offcuts with the final sanding grit—use them to test stain/clear behavior before touching the actual project.

FAQs

• Can I replace 120 with 150? Yes—on smoother stock or veneer-sensitive jobs, 100?150?180 or 120?150?180 works well. The principle is keeping jumps small enough to fully erase scratches.
• Is 220 always necessary? No. Use it deliberately for ultra-clear finishes or blotch-prone woods. On many projects, 180 is the ideal stop.
• What about going finer than 220 before stain? Often counterproductive—too fine can reduce color uptake. Test on scrap at your final grit.
• Why are my swirls back after finish? They were never fully removed. Revisit the grit before the problem appeared, use raking light, and restore the sequence.
• Do I need wet-sanding here? Not for raw wood prep. Wet-sanding is great later for high-gloss film leveling; initial prep is almost always dry.

Video: See Balanced Grit Jumps in Action

Bottom line: Respect the scratch ladder. An 80?120?180 progression removes defects faster, leaves a cleaner scratch field, and sets you up for flawless stain and topcoat. Stick to disciplined steps, verify with light, and your finish will thank you.