Epoxy River Table Sanding: 80–240 Dry, 400–3000 Wet Guide

Epoxy river tables combine the warmth of wood with the glassy depth of resin—but that showroom clarity only happens when your sanding is disciplined. This guide gives you a proven, repeatable workflow: 80→240 dry to flatten and unify, then 400→3000 wet to erase micro-scratches and unlock a liquid finish ready for polishing. Follow the sequence, keep your pressure light, and let sharp, wet-or-dry silicon carbide sheets do the work.

Why Sanding Matters on River Tables

Resin and wood cut differently. Epoxy can gum or haze if overheated; wood can dish or round at edges if you lean too hard. Correct sanding does three things: (1) levels tool marks, drips, and proud resin, (2) unifies the resin–wood transition so it feels seamless, and (3) tightens the scratch pattern so polishing reaches a mirror-like gloss quickly. Skipping grits, pushing pressure, or staying dry too long creates cloudy patches and witness lines you’ll chase later.

Tools You’ll Need

• Wet/dry silicon carbide sandpaper sheets (e.g., 80, 120, 180, 240 dry; 400, 600, 800, 1000, 1500, 2000, 3000 wet).
• Random orbital (DA) sander with dust extraction and a soft interface pad (5–10 mm) for resin transitions.
• Hard sanding block (for flats) + soft foam pad (for gentle contours/live-edge zones).
• Raking light and a pencil for crosshatch “map” marks; straightedge for flatness checks.
• Spray bottle with clean water + a drop of dish soap (wet sanding lubricant), squeegee, and microfiber towels.
• PPE: respirator (P100), eye & ear protection; epoxy and wood dust are not your friends.
• Compounds and pads for the final buff (medium-cut then finish polish), optional UV-protective topcoat.

Recommended Grit Sequence

• 80 grit (dry): Fast leveling of tool marks, drips, and ridges without overheating the resin.
• 120/180 grit (dry, optional): Intermediate refinement if your 80-grit tracks are deep or you’ve flattened a lot.
• 240 grit (dry): Final dry step to unify the surface before switching to wet.
• 400 → 600 → 800 (wet): Removes the dry-stage scratch field and prevents haze.
• 1000 → 1500 → 2000 → 3000 (wet): Tightens micro-scratches for near-mirror clarity ahead of polish.

Step-by-Step: From Rough Level to Polish-Ready

1. Flatten & clean setup. Vacuum thoroughly so stray grit doesn’t gouge the resin. Mark the surface with a light pencil crosshatch and position a raking light. Keep the table well supported to avoid flex, which creates wavy sanding.
2. Level at 80 grit (dry). With a soft interface pad and a light touch, make long, overlapping passes. Stay moving to avoid heat. For aggressive but controlled leveling, start with 80 Grit (25-pack). Refresh the sheet as soon as cut slows—dull paper polishes, then scratches.
3. Check flatness & trouble spots. Squeegee a little water across the surface; reflections reveal highs/lows instantly. Re-mark only the low spots and blend them at 80 (briefly) rather than over-sanding the entire panel.
4. Intermediate smoothing (optional). If you removed a lot at 80 or see deep tracks, take a short pass at 120 or 180 to make 240 go faster. Keep the pad flat; tipping near live edges creates scallops you’ll fight later.
5. Unify with 240 grit (dry). Replace every coarser scratch with a tight, even pattern. Alternate your pass direction slightly (then finish with the grain of the wood) so lingering 80/120 lines stand out. Lock in the dry phase with 240 Grit (50-pack).
6. Switch to wet at 400. Mist the surface with water (1 small drop of dish soap per bottle helps float swarf). Sand at 400 wet using light pressure; every few strokes, squeegee a clear patch and look in the reflection—if you still see directional 240 lines, stay at 400 until they’re gone.
7. Clarity ladder: 600 → 800 → 1000. Work methodically in manageable zones. After each grit, rinse, squeegee, and inspect. The goal is complete removal of the previous pattern—don’t rush the transitions or you’ll trap a coarse scratch that only appears after polish.
8. Fine finishing: 1500 → 2000 → 3000. These steps are quick when the earlier work is thorough. Keep strokes long and pressure feather-light. For that final pre-polish glide and gloss, finish with 3000 Grit (100-pack). If you see a random halo under raking light, back up one grit in a small area, fix it, and re-advance.
9. Polish (optional but recommended). Dry the surface completely. Use a medium-cut compound on a foam pad at low speed, then a finishing polish to maximize depth. Avoid catching edges and keep pads clean—contamination introduces new scratches.
10. Clean & protect. Wipe down with a resin-safe cleaner. If the table will see sun, consider a clear coat with UV blockers or maintain with compatible protectants to slow ambering.

Special Cases

Tinted or metallic epoxy: Coarse scratches telegraph under translucent color. Spend extra time at 400–800 to ensure a perfectly even field before moving finer.
Soft void fills & inclusions: Bark, soft punky wood, or embedded items cut faster than resin. Hand-sand these zones on a soft pad and keep pressure minimal to avoid cupping.
Heat risk on edges: Arrises concentrate pressure and heat; use hand strokes with the grain and pause often to cool.
Dust pinholes/bubble nibs: Slice proud nibs flush with a sharp razor held flat, then resume at the current grit. Don’t try to “grind them out” with a DA—they smear.

Pro Tips

• Time-on-grit discipline: Don’t move up until the previous scratch pattern is 100% gone under a squeegee check.
• Keep it cool: Light pressure, fresh sheets, and motion prevent resin haze and galling.
• Block the flats, pad the curves: Use a firm block to keep panels flat; switch to a soft pad only where the profile demands it.
• Clean between steps: Rinse, wipe, and brush the abrasive face. Rogue coarse grains create mystery scratches.
• Change water often: Dirty slurry re-deposits grit; fresh water = faster clarity.
• Guide coat trick: A light pencil crosshatch before each dry grit shows when you’ve removed enough—no guesswork.

Aftercare

• Let polishes or topcoats cure fully before heavy use. Fresh films are soft and scratch easily.
• Use pH-neutral cleaners; household ammonia can haze certain clear coats.
• Consider coasters and soft pads under décor—micro-scratches are most visible on dark or highly tinted pours.
• Plan seasonal maintenance: a quick 2000→3000 wet re-fresh and light polish restores sparkle without resetting the whole sequence.

FAQs

• Can I start at 120 instead of 80? Yes—if the surface is already flat. Use 80 only for real leveling (ridges/drips). Starting finer reduces deep tracks.
• Dry-sand the whole process? You can, but resin clarity improves dramatically when you switch to wet at 400 and up.
• Do I need all the wet grits? You can step 400 → 800 → 1500 → 3000 if your 240 work is excellent; just verify no intermediate scratches remain.
• Why is there a cloudy patch after polishing? Heat or trapped coarse scratches. Cool down, back up one or two grits in that spot, and re-advance.
• What about live edges? Hand-sand with a soft pad; DA tipping there creates scallops and reveals as shiny flats after polish.

Watch & Learn

Bottom line: Keep pressure light, confirm each step under a squeegee, and follow the simple ladder—80 → 240 (dry) then 400 → 3000 (wet). Stock the key sheets so you can stay disciplined at the critical steps: start with 80 Grit (25-pack), lock in the dry phase with 240 Grit (50-pack), and finish clarity fast with 3000 Grit (100-pack).