Epoxy River Table Calculator

A river table has two components: the channel fill (deep pour resin) and the tabletop flood coat. This guide helps you calculate both, with volume tables by channel size, a void fill percentage reference, and layer planning for deep pours.

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Channel Volume Formula

Channel volume (fl oz) = channel length (in) × avg. channel width (in) × pour depth (in) ÷ 1.805
Add 15% for wood grain absorption: total × 1.15

Measure the channel width at 5 evenly spaced points and use the average. River channels are rarely uniform — this averaging step is critical for an accurate estimate.

Channel Volume Quick Reference

Estimates below are for the channel fill only, before the tabletop flood coat. Includes 15% waste/absorption buffer.

Table LengthAvg Channel WidthPour DepthChannel Fill
4 ft (48 in)4 in2 in~24 fl oz
4 ft (48 in)6 in2 in~36 fl oz
5 ft (60 in)6 in2 in~45 fl oz
6 ft (72 in)6 in2 in~54 fl oz
6 ft (72 in)8 in2 in~73 fl oz
6 ft (72 in)8 in2.5 in~91 fl oz
7 ft (84 in)8 in2.5 in~106 fl oz
8 ft (96 in)8 in2.5 in~122 fl oz
8 ft (96 in)10 in3 in~190 fl oz

Tabletop Flood Coat

After the channel cures, the full tabletop surface gets a flood coat of table-top epoxy (not deep pour). This is calculated separately based on the full table dimensions.

Table SizeSurface AreaSeal Coat (1/16")Flood Coat (1/8")Both Coats Total
24 × 48 in8 sq ft~18 fl oz~36 fl oz~54 fl oz
24 × 60 in10 sq ft~23 fl oz~46 fl oz~69 fl oz
30 × 72 in15 sq ft~34 fl oz~68 fl oz~102 fl oz
36 × 84 in21 sq ft~48 fl oz~96 fl oz~144 fl oz
36 × 96 in24 sq ft~55 fl oz~110 fl oz~165 fl oz

Typical Total for a 6-Foot River Table (30" × 72")

ComponentAmountProduct Type
Channel fill (6" wide, 2" deep)~54 fl ozDeep pour casting resin
Seal coat (full table)~34 fl ozTable-top epoxy
Flood coat (full table)~68 fl ozTable-top epoxy
Grand total~156 fl oz (~1.2 gal)Two separate products

River Table Build Tips

  1. Seal the wood first: Brush undiluted deep-pour resin onto all exposed wood surfaces and let it tack up before the main fill. This prevents air bubbles from wood grain rising into the pour.
  2. Build a form: Tape Tyvek tape or wax release film to the underside and edges of the slab to contain the pour. Check all edges for leaks before mixing large batches.
  3. Level the slab: Set the table form perfectly level — use a long spirit level and shims. Epoxy will find any tilt.
  4. Pour in layers: For channels deeper than 2 inches, pour in two stages. Wait until the first layer reaches firm gel (not fully cured) before adding the second pour.
  5. Flood coat after full cure: Wait a full 72 hours after the final channel fill pour before applying the tabletop flood coat.

Frequently Asked Questions

How much epoxy do I need for a river table?

For a 6-foot table with a 6-inch wide, 2-inch deep channel: ~54 fl oz of deep pour resin for the channel. Add ~102 fl oz of table-top epoxy for seal coat + flood coat on the full 30×72 inch surface. Total: ~156 fl oz (~1.2 gallons) across two different products.

What epoxy is best for a river table?

Use a deep pour casting resin rated for at least 2 inches per pour for the channel fill. For the tabletop flood coat, use a separate high-gloss table-top epoxy with UV resistance. Avoid using deep pour resin for the top coat — it's too soft and not designed for surface applications.

How do I calculate the void in a river table?

Measure the channel width at 5 evenly spaced points along the table length, then average them. Multiply average width × table length × pour depth, divide by 1.805 to get fl oz, then add 15% for wood absorption.