River Table Epoxy Calculator: How Much and How Many Pours
Enter the river's length, its narrowest and widest points and the slab thickness to get the epoxy to mix, the Part A / Part B split and a pour schedule that stays within the maker's thickest pour.
Your measurements
Pick your epoxy and enter the size. Everything updates as you type.
Epoxy
A 1:1 semi-deep-pour epoxy: up to 1/2" per layer for river tables and slabs, up to 2" for small castings. Pour builds thicker than 1/2" as 1/2" layers at least 4 hours apart; no sanding needed between layers. (The current formula is 1:1; older ThickSet kits were 3:1, so check your label.)
River
End to end along the table.
For a very uneven river, measure every foot or so and use the average for both.
Pour
Usually the slab thickness, measured at the river's edge.
Common
10% covers the cup, stirrer and drips. Use 15–20% for live edges, bark and open grain that soak up epoxy.
Results
Total epoxy to mix
L
= 4.11 gal
Average width 8" · 203.2 mm, plus 10% for the cup, drips and the wood. Mix 1:1 by volume, 1.11:1 by weight.
- Part A (resin)
- 7.79L
- = 2.06 gal
- or 8.93 kg by weight
- Part B (hardener)
- 7.79L
- = 2.06 gal
- or 8.05 kg by weight
- Batch weight
- 16.98kg
- = 37.43 lb
- At 1.09 g/cm³
- Layers
- 3× 1/2" · 12.7 mm
- Mix each in 2 batches
Pour schedule
Pour builds thicker than 1/2" as 1/2" layers at least 4 hours apart; no sanding needed between layers. (The current formula is 1:1; older ThickSet kits were 3:1, so check your label.)
| Layer | Fills to | Mix | Part A | Part B |
|---|---|---|---|---|
| 1 | 1/2" · 12.7 mm | 5.19 L | 2.6 L | 2.6 L |
| 2 | 1" · 25.4 mm | 5.19 L | 2.6 L | 2.6 L |
| 3 | 1 1/2" · 38.1 mm | 5.19 L | 2.6 L | 2.6 L |
Mix each layer in 2 batches of about 2.6 L: the maker limits how much to mix at once.
How this was calculated
Area, volume, waste, the split and the layers, with your numbers.
How this was calculated
Area, volume, waste, the split and the layers, with your numbers.
Step 1: Area of the river
length × (narrowest + widest) ÷ 2
= 72″ (1828.8 mm) × (6″ (152.4 mm) + 10″ (254 mm)) ÷ 2
= 576 in²Averaging the narrowest and widest points treats the river as a straight-sided channel. For a very uneven river, measure the width every foot or so and average all of them.
Step 2: Volume to fill
area × depth
= 576 in² × 1.5″ (38.1 mm)
= 14,158 mL (478.8 fl oz)1 cm³ is 1 mL, and 1 US fl oz is 29.57 mL.
Step 3: Add the waste allowance
volume × (1 + waste %)
= 14,158 mL (478.8 fl oz) × 1.1
= 15,574 mL (526.6 fl oz)Covers what stays in the cup and on the stirrer, drips over edges and soaks into wood. Seal-coat bare wood first so it does not drink the flood coat.
Step 4: Split by the volume ratio
Part A = total × 1 ÷ 2, Part B = total × 1 ÷ 2
= 15,574 mL × 1/2 and × 1/2
= A 7,787 mL (263.3 fl oz), B 7,787 mL (263.3 fl oz)TotalBoat ThickSet mixes 1:1 by volume. Measure in graduated cups, then mix and transfer to a second cup.
Step 5: Weight of the batch
weight = volume × density; Part A = weight × 1.11 ÷ 2.11
= 15,574 mL × 1.09 g/cm³
= 16,976 g: A 8,930 g, B 8,045 gBy weight the ratio is 1.11:1, not 1:1, because the resin is denser than the hardener. Weighing is the more accurate way to measure.
Step 6: Layers
layers = ⌈depth ÷ thickest layer⌉
= ⌈1.5″ (38.1 mm) ÷ 0.5″ (12.7 mm)⌉
= 3 layers of 0.5″ (12.7 mm) (5,191 mL (175.5 fl oz) each)The thickest layer is the maker's limit for one pour; thicker pours trap heat and can yellow, crack or ripple. Mix each layer in 2 batches to stay under the maker's mixing limit.
Sources
TotalBoat ThickSet Epoxy: mix ratios, density and thickest pour
Checked against sourceChecked against the maker's documentation. Checked 24 Oct 2026.
- TotalBoat ThickSet Epoxy Instruction Sheet and TDS (1A:1B by volume, 1.11A:1B by weight; resin ~1.15 and hardener ~1.03 g/cm³; max 1/2" per coat, layers ≥4 hours apart; small castings up to 2" and 10 fl oz per pour; do not mix more than 1 gallon at a time.), opened 24 Oct 2026
Average of the resin (1.15 g/cm³) and hardener (1.03 g/cm³) densities at 1:1 by volume. The data sheet lists a cured density of about 1.08 g/cm³.
In short
Epoxy to mix = area × depth + about 10%. A 72"″ river, 6"″ to 10"″ wide and 1 1/2"″ deep, needs about 15,574 mL (4.11 gal) of TotalBoat ThickSet with 10% extra, in 3 layers of 1/2"″.
Deep-pour figures come from each maker's data sheet.
Epoxy mix ratios, density and thickest pour
Figures from each maker's data sheet, checked on the date in the sources. Weight ratios come from the maker; densities are the mixed liquid unless marked.
| Epoxy | Use | Mix ratio | Density (g/cm³) | Thickest pour |
|---|---|---|---|---|
| TotalBoat TableTop Epoxy | Coating | 1:1 by volume, 1.2:1 by weight | 1.05 | 1/4"″ (6.4 mm) |
| ArtResin Epoxy Resin | Coating | 1:1 by volume, 100:84 by weight | 1.051 | 1/8"″ (3.2 mm) |
| EcoPoxy UVPoxy | Coating | 1:1 by volume, 1.2:1 by weight | 1.07 (cured) | 1/8"″ (3.2 mm) |
| TotalBoat ThickSet Epoxy | Deep pour | 1:1 by volume, 1.11:1 by weight | 1.09 | 1/2"″ (12.7 mm) |
| EcoPoxy FlowCast | Deep pour | 2:1 by volume, 2.3:1 by weight | 1.07 (cured) | 1/2"″ (13 mm) to 1 1/2"″ (38 mm) |
| MAS Deep Pour X | Deep pour | 2:1 by volume, 100:43 by weight | 1.0625 | 2"″ (50.8 mm) to 3"″ (76.2 mm) |
Pour limits assume the working temperature on each label. Warmer rooms and larger pours cure hotter, so check your label before pouring.
Worked example: TotalBoat ThickSet
Area, then volume, waste, the split between the parts and the pours.
Step 1: Area of the river
length × (narrowest + widest) ÷ 2
= 72″ (1828.8 mm) × (6″ (152.4 mm) + 10″ (254 mm)) ÷ 2
= 576 in²Averaging the narrowest and widest points treats the river as a straight-sided channel. For a very uneven river, measure the width every foot or so and average all of them.
Step 2: Volume to fill
area × depth
= 576 in² × 1.5″ (38.1 mm)
= 14,158 mL (478.8 fl oz)1 cm³ is 1 mL, and 1 US fl oz is 29.57 mL.
Step 3: Add the waste allowance
volume × (1 + waste %)
= 14,158 mL (478.8 fl oz) × 1.1
= 15,574 mL (526.6 fl oz)Covers what stays in the cup and on the stirrer, drips over edges and soaks into wood. Seal-coat bare wood first so it does not drink the flood coat.
Step 4: Split by the volume ratio
Part A = total × 1 ÷ 2, Part B = total × 1 ÷ 2
= 15,574 mL × 1/2 and × 1/2
= A 7,787 mL (263.3 fl oz), B 7,787 mL (263.3 fl oz)TotalBoat ThickSet mixes 1:1 by volume. Measure in graduated cups, then mix and transfer to a second cup.
Step 5: Weight of the batch
weight = volume × density; Part A = weight × 1.11 ÷ 2.11
= 15,574 mL × 1.09 g/cm³
= 16,976 g: A 8,930 g, B 8,045 gBy weight the ratio is 1.11:1, not 1:1, because the resin is denser than the hardener. Weighing is the more accurate way to measure.
Step 6: Layers
layers = ⌈depth ÷ thickest layer⌉
= ⌈1.5″ (38.1 mm) ÷ 0.5″ (12.7 mm)⌉
= 3 layers of 0.5″ (12.7 mm) (5,191 mL (175.5 fl oz) each)The thickest layer is the maker's limit for one pour; thicker pours trap heat and can yellow, crack or ripple. Mix each layer in 2 batches to stay under the maker's mixing limit.
Epoxy: common questions
Volume, mix ratios, waste and pour depth.
How do I calculate how much epoxy a river table needs?
Multiply the river length by its average width (narrowest plus widest, halved) and by the depth, then add 10–20% for waste and what the wood soaks up. A 72"″ river, 6"″ to 10"″ wide and 1 1/2"″ deep, needs about 15,574 mL (4.11 gal) of TotalBoat ThickSet with 10% extra, in 3 layers of 1/2"″.
How deep can I pour deep-pour epoxy in one go?
It depends on the product: TotalBoat ThickSet allows up to 1/2″ per pour, EcoPoxy FlowCast 1/2″–1-1/2″ and MAS Deep Pour X up to 3″ (with at least 2″, or it cures slowly). Pouring deeper than the limit traps heat and can crack, yellow or bubble the resin. The calculator splits the pour into equal layers within the limit.
Should I measure Part A and Part B by volume or by weight?
Use the basis on the label. Resin and hardener have different densities, so a 1:1 by volume epoxy is not 1:1 by weight: TotalBoat ThickSet is 1:1 by volume, 1.11:1 by weight. The calculator gives both, using the part densities from the data sheet.
How much extra epoxy should I mix?
About 10% covers what stays in the cup, on the stirrer and what drips off the edges. Live edges, bark and open-grain wood soak up more, so use 15–20% there, or seal the wood with a thin coat first. The calculator does not model shrinkage; the extra covers it.