Sand Epoxy River Tables: 80–240 Dry, 400–3000 Wet

Epoxy river tables look like still water flowing through wood—but only if the surface is truly flat and the micro-texture is refined in tight steps. The fastest path to that glassy look is simple: dry-sand the poured slab to level and remove router/sled marks (typically up to 180–240), then switch to wet-sanding through fine grits (400→800→1500→3000) and finish with a controlled compound/polish. This guide lays out a cool, clean workflow that protects edges, prevents cloudy haze, and keeps the scratch field uniform so your reflection pops.

Why Sanding Matters on River Tables

Epoxy cures hard, but the top microns are unforgiving: deep scratches telegraph, heat smears resin, and uneven leveling leaves shiny islands that never polish out. A disciplined sequence (1) sets the plane across both wood and resin, (2) replaces scratches in predictable steps so you’re compounding off a fine, uniform haze—not grooves, and (3) controls heat with light pressure, fresh sheets, and water at the right time.

Tools & Supplies

• Random-orbital (DA) sander with variable speed and a firm pad for flats; thin foam interface (2–3 mm) only for gentle crowns.
• Hand sanding blocks: one firm (panels/edges) and one thin foam (profiles and live edges).
• Dry grits for leveling: 80, 120, 150/180, 220/240.
• Wet grits for clarity: 400, 600, 800, 1500, 2000, 3000 (silicon-carbide preferred).
• Spray bottle with clean water + 1 drop dish soap, rubber squeegee, lint-free microfibers.
• Compounds: medium-cut and finishing polish; foam cutting and finishing pads.
• Vacuum/dust extractor, raking/inspection light, pencil for witness marks, painter’s tape.
• PPE: respirator (P100), eye/ear protection; work in shade on a cool surface.

Recommended Grit Sequence

• Dry level: 80 → 120 → 150/180 → 220/240.
• Wet refine: 400 → 600 → 800 → 1500 → 2000 → 3000.
• Buff: compound (low–medium speed) → finishing polish.

Step-by-Step: Flat, Clear, and Glossy

1. Flatten before sanding. After the pour cures fully, knock down major irregularities with a router sled or wide sander. Remove dust, then pencil a light crosshatch over the whole slab—witness marks tell you when each grit is done.
2. Dry-sand at 80–120 (as needed). Use a DA at low–medium speed with a firm pad. Keep the pad dead-flat, pressure feather-light, and strokes long/overlapping. Stop the 80 pass the instant sled lines and obvious highs are gone; step to 120 to replace 80 scratches and unify wood + resin.
3. Refine the plane at 150/180 → 220/240. Change direction slightly each step (then finish with the table’s long axis) so leftover scratches pop. For a predictable mid-step cut that bridges wood and epoxy cleanly, stock 120 Grit (25-pack) for the early refinement and use it judiciously to avoid digging ridges.
4. Edge discipline. Mask knife-sharp arrises. Do borders and live edges by hand on a firm block; switch to a thin foam hand pad only to ease organic contours. Count strokes—most burn-throughs happen at corners.
5. Switch to wet at 400. Vacuum, then mist water + a drop of soap. Wrap SiC paper on a flat mini-block (foam interface only for gentle crowns). With light, overlapping strokes, build a uniform, dull sheen. Squeegee every minute—shiny dots are untouched highs.
6. Clarity steps: 600 → 800. Rinse, re-lube, and slightly change your stroke angle. Replace all prior lines with a tighter field. The 800 pass is your clarity pivot—keep it cool and flat. A reliable sheet for this stage is 800 Grit (50-pack); it cuts quickly without loading when you keep slurry moving.
7. Pre-polish: 1500 → 2000 → 3000. Step through fine grits quickly—two or three light passes each. After 3000, the surface should show a uniform, ultra-fine haze with no visible directional lines. Set yourself up for a fast, low-heat polish by finishing with 3000 Grit (100-pack).
8. Clean and dry. Rinse off slurry, blow out cracks/voids, and wipe with lint-free microfibers. Let residual water flash completely before compounds.
9. Compound, then polish. DA polisher, foam cutting pad, moderate compound, low–medium speed. Keep the pad flat, minimal pressure, work in small sections. Stop as soon as the 3000 haze clears. Switch to a finishing polish/pad for depth and pop. If a faint trail remains, re-enter locally at 2000 → 3000, then brief compound.
10. Final inspect & seal. Check under raking light from multiple angles. If you want extra slickness, apply a compatible sealant/wax after polish oils are removed per product directions.

Special Cases

Bubbles, dust nibs, or small highs: Knock spikes first with a nib file or 400 on a firm mini-block, then blend the halo 400→600→800 and continue.
Soft or under-cured epoxy: If paper gums or smears, stop and allow more cure. Gummy resin won’t finish cleanly.
Live edges: Keep machines off bark/soft transitions; hand-sand with a thin foam pad, then return to a firm block for adjacent flats to avoid flats/facets.
Deep router tracks or tilt marks: Reset briefly at 120–150 on a flat backer, then rebuild the ladder—don’t try to “polish them out.”

Pro Tips

• Flat block = flat reflection. Fingers dig troughs that print under gloss; always block flats, foam only for gentle crowns.
• Fresh sheets beat pressure. The moment cut slows, rotate to a new quadrant. Pressure makes heat—and heat makes haze.
• Read with a squeegee. Wipe slurry often; shiny islands mean you haven’t fully leveled at that grit.
• Alternate directions. Subtle angle changes expose leftover scratches before you climb.
• Keep it cool & clean. Cool panel, clean pads, clean water. One rogue grain trapped under paper = one permanent pigtail.

Aftercare

• Let polish oils flash before adding any sealant or wax; follow product timing.
• Use pH-neutral cleaners and soft cloths; avoid abrasives that can dull epoxy.
• Protect from hot cookware; use trivets—thermal shock can haze resin.
• For micro-swirls months later, a quick 3000 wet spot and a finishing polish usually restores clarity.

FAQs

• Can I jump from 240 dry straight to 1500 wet? Not cleanly. Hit 400/600 first so your compound doesn’t chase deep scratches.
• Is 120 too coarse on epoxy? It’s fine for removing router lines if you move quickly and keep the pad flat. Replace 120 lines fully at 150/180 → 220/240.
• Why do I see cloudy haze after polishing? Usually heat or incomplete refinement. Re-enter locally at 800 → 1500 → 3000 (wet), then polish lightly with a clean pad.
• Machine wet-sanding okay? Yes—low speed, foam-backed discs, pad flat, and frequent rinsing. Finish each grit by hand on a flat block to verify uniformity.
• Do I need to sand the wood differently? Keep the same ladder across wood and epoxy so the reflection doesn’t “step” at the boundary.

Watch & Learn

Closing: River-table gloss isn’t luck—it’s sequence and touch. Dry-sand to set a truly flat plane, then wet-refine in tight steps so compound work stays cool and quick. Keep the exact sheets on hand so you stick to the plan: refine early cuts with 120 (25-pack), lock in clarity at 800 (50-pack), and leave a fast-to-polish haze with 3000 (100-pack). Follow the ladder, keep it flat and cool, and your river will look like glass.