Level Post-Epoxy Flood Coats: Razor Plane & 120?220

Epoxy flood coats can look wavy or develop random high spots after cure. Leveling them flat without cutting through the finish takes a precise sequence: knock down ridges mechanically, then sand in controlled steps so your next coat lays dead-flat. This guide explains why sanding matters, which tools to use, and how to move from a razor plane to a tight 120?220 scratch profile—without introducing new waves.

Why Leveling Matters

Even a well-poured flood coat can cure with sags, dust nibs, or standing ridges. If you simply “polish” them with fine paper, you’ll round highs and leave the surface uneven. A disciplined level-and-sand workflow removes the peaks first, then refines the entire surface to a uniform scratch field. That way, your next flood coat or polish step reads as a mirror, not a funhouse.

Tools You’ll Need

• Sharp razor plane, cabinet scraper, or razor blade in a safe holder
• Long, hard sanding block (or a dead-flat surrogate like phenolic/MDF)
• Random-orbit sander with dust extraction and a soft interface pad (for blending)
• 9×11 in wet/dry silicon carbide sheets: 120, 180, 220 (and optional 320)
• Pencil for guide-coat, bright raking light, straightedge
• Vacuum with brush head, microfiber cloths, and tack cloth
• PPE: respirator (P100), eye & hearing protection; gloves

Recommended Grit Sequence

• 120 grit — First uniform cut after shaving ridges; establishes flatness.
• 180 grit — Scratch refinement to erase 120’s trenches.
• 220 grit — Final pre-finish surface for the next flood coat or polish path.
• Optional 320 grit — Light de-nib before a very thin topcoat or for satin finishes.

Step-by-Step: Flat Without Waves

1. Shave the highs safely. Skew a razor plane or cabinet scraper across obvious ridges at a low angle. Take whisper-thin shavings until the peaks blend with the field. Keep the tool flat—you’re leveling, not digging.
2. Pencil-map and check flatness. Lightly pencil a crosshatch over the whole surface. Use a long straightedge under raking light to find crowns/valleys. The pencil guide tells you when sanding has reached every spot.
3. Uniform cut at 120 grit. Wrap paper around a long, hard block and make overlapping strokes with even pressure. Sand until all pencil marks vanish uniformly. For consistent, clog-resistant sheets at this stage, use 120 grit (25-pack). Avoid finger sanding—bare fingers create divots that reappear under finish.
4. Blend transitions. Where the block can’t reach (edges, radiuses), switch to a random-orbit with a soft interface pad and feather very lightly so you don’t dish the surface. Re-mark pencil on those zones to verify coverage.
5. Refine to 180 grit. Re-map with pencil and sand just until 120’s scratches are gone—no more. This step is fast; over-sanding rounds things off. For an efficient refinement, step to 180 grit (50-pack).
6. Final pre-finish at 220 grit. Make a brief, even pass to set a tight scratch field that disappears under the next coat. Stop the moment the surface is uniformly matte. Stock up on 220 grit (100-pack) for larger projects and flawless prep.
7. Dust control & inspection. Vacuum thoroughly, wipe with a clean microfiber, and check under raking light from multiple directions. Any shiny islands or deep scratches? Back up one grit locally and blend.
8. Next step: topcoat or polish. For a fresh flood coat, follow the epoxy maker’s recoat window—if you’re outside it, do a light 220 scuff again just before coating. For a polish route, proceed 320?600?1000+ wet, then compounds.

Special Cases

Soft/green epoxy: If the coat gums up or rolls under paper, it hasn’t cured—wait until it powders.
Dust nib clusters: Spot level with the razor, then 180?220 just in that area; avoid re-sanding the whole field.
Deep sags/runs: Cross-shave with the razor to near-flat, then block 120 with short, straight strokes. Keep strokes parallel to edges to avoid scallops.
Embedded debris: Digging risks craters. Instead, shave flush and plan a thin flood coat to bury remaining pinholes.

Pro Tips

• Always start with mechanical leveling (razor/scraper) before sanding—paper alone rounds highs.
• Use a long, hard block for true flatness; reserve the RO + soft pad for feathering only.
• Keep the pad/block flat and pressure light. Heat and pressure cause smears and wavy cuts.
• Pencil + raking light is your cheapest QC system—re-mark between grits.
• Replace dull paper early; dull sheets polish instead of cutting and hide deeper scratches.

Aftercare

• Respect cure windows and temperatures for the next flood coat.
• Maintain a dust-controlled space—run filtration and tack between coats.
• For tabletops/bars, consider a thin seal coat over the leveled surface before the final flood to lock down ultra-fine scratches.
• Protect the surface from heat and UV; use coasters and avoid hot pans.

FAQs

• Can I start at 80 grit? Not on cured epoxy—too aggressive and prone to gouging. Shave mechanically, then start at 120.
• Do I need to wet-sand? Not for leveling. Wet-sanding is great later (320?600?1000+) for polish; keep leveling dry for flatness.
• Why do waves keep returning? Sanding with a soft pad or fingers rounds highs. Use a long, hard block for the 120 pass.
• Will 320 reduce adhesion? If recoating thin, keep 220 as your last prep; use 320 only as a light de-nib right before a thin topcoat.
• What if I hit wood at an edge? Feather that spot, seal with a compatible barrier (e.g., thin epoxy sealer), then re-level lightly at 220 before the next coat.

Watch the Workflow

Closing: The recipe for flat, glassy epoxy is simple: shave peaks ? 120 block ? 180 refine ? 220 finish. Control flatness with a long block, verify with light, and keep dust down. Your next coat—or your polish—will lay out like glass.