Deep Pour Epoxy Calculator for River Tables
Accurately estimate 1" to 4" thick casting pours using 5-point irregular river channel widths, live-edge bark slope compensation, and exothermic layer checks.
Measure the gap between your left and right wood slabs at 5 evenly spaced marks along the mold length:
Exact Volume & Scale Weight
Buy a 1.5-Gallon Kit (or 1 Gal + 2 Quarts)
*Note: Resin is heavier than hardener (1.15 vs 0.97 g/mL), so a 1:1 volume mix weighs ~1.18:1 on a gram scale. Always verify against your bottle label.
How to Measure an Irregular River Table Channel in 4 Steps
Building a live-edge river table is one of the most rewarding woodworking projects, but standard rectangular calculators fail completely when two organic wood slabs wind and curve through your mold box. Because natural timber edges are neither straight nor perpendicular, a simple length-times-width estimate can leave you short by half a gallon onpouring day.
This dedicated deep pour calculator solves irregular channel geometry in two ways: you can measure the river gap at five points along the mold (W1 to W5) and apply a live-edge bevel multiplier for sloped bark edges, or subtract your wood slab volume from the outer form dimensions. It also checks your target thickness against the 2-inch exothermic safety limit and breaks your batch into Part A and Part B gram weights for 2:1 and 3:1 slow-cure casting systems.
1. Measure Mold Length & Target Depth
Measure the inside length of your melamine or HDPE form box and the finished thickness of your flattened hardwood slabs (typically 1.5" to 2.5").
2. Record 5 Channel Widths (W1–W5)
Divide the table length into four equal quarters and measure the gap between the left and right wood slabs at the start, 25%, 50%, 75%, and end marks.
3. Apply Live-Edge Bevel Compensation
Natural waney edges slope outward underneath the top surface. Enable the +10% Live-Edge Bevel factor so undercut bark cavities do not drain your pour level.
4. Check Exothermic Layer Count
If your pour exceeds 2.0 inches, review the automatic multi-layer split recommendation to keep peak curing temperatures below 140°F (60°C).
Deep Pour Casting Math: Multi-Point Integration vs. Slab Subtraction
Every calculation in our workbench uses exact US customary (NIST) and metric physical constants with zero rounding drift:
- Rectangular Volume (in³):
Volume = Length (in) × Width (in) × Depth (in) - Circular / Round Table Volume (in³):
Volume = π × (Diameter ÷ 2)² × Depth (in) - Irregular 5-Point River Channel (in³):
Volume = Length × ((W1 + W2 + W3 + W4 + W5) ÷ 5) × Depth × LiveEdgeFactor - Cubic Inches to US Fluid Ounces:
Fluid Ounces = Cubic Inches × 0.554112554(1 US Gallon = 231 in³ = 128 fl oz) - Volumetric Ratio to Digital Scale Weight (Grams):
Part A Grams = Part A mL × 1.15andPart B Grams = Part B mL × 0.97 - Garage Floor Mil Coverage:
Sq.Ft per Gallon = 1,604 ÷ Thickness in Mils(at 100% volume solids)
River Table Volume Chart by Channel Width and Pour Depth
Deep casting volume for a 72-inch (6-foot) river table across common average river widths and slab thicknesses (includes +10% live-edge bevel allowance):
| River Length | Avg Channel Width | 1.5" Slab Depth | 1.75" Slab Depth | 2.0" Slab Depth | 3.0" Thick Slab (2 Layers) |
|---|---|---|---|---|---|
| 60" (5 ft Table) | 6" Narrow Stream | 329 fl oz (2.57 gal) | 384 fl oz (3.00 gal) | 439 fl oz (3.43 gal) | 658 fl oz (5.14 gal) |
| 72" (6 ft Dining) | 8" Medium River | 527 fl oz (4.11 gal) | 614 fl oz (4.80 gal) | 702 fl oz (5.49 gal) | 1,053 fl oz (8.23 gal) |
| 72" (6 ft Dining) | 10" Wide River | 658 fl oz (5.14 gal) | 768 fl oz (6.00 gal) | 878 fl oz (6.86 gal) | 1,317 fl oz (10.29 gal) |
| 84" (7 ft Dining) | 10" Wide River | 768 fl oz (6.00 gal) | 896 fl oz (7.00 gal) | 1,024 fl oz (8.00 gal) | 1,536 fl oz (12.00 gal) |
| 96" (8 ft Conference) | 12" Grand River | 1,053 fl oz (8.23 gal) | 1,229 fl oz (9.60 gal) | 1,404 fl oz (10.97 gal) | 2,106 fl oz (16.46 gal) |
Preventing Exothermic Runaway, Yellowing & Shrinkage in Thick Pours
1. Temperature Control (70°F–75°F)
Cold workshop air thickens liquid components and traps micro-bubbles. Warm sealed Part A and Part B bottles in a warm water bath for 15 minutes before measuring to achieve crystal-clear self-leveling flow.
2. Double-Cup Scrape Method
Scrape the sides and bottom of your mixing bucket for 3 full minutes, then transfer the blend into a second clean bucket and stir for 60 more seconds. Unmixed wall residue causes permanent sticky soft spots.
3. Torch & Heat Gun Bubble Release
Pass a propane torch or heat gun rapidly across the wet surface 15 minutes after pouring, and check again at 45 minutes. Heat momentarily lowers surface viscosity so trapped air pops cleanly.
Every epoxy batch should be mixed slowly for full curing. Check epoxy studio temperature before pouring epoxy into a wood mold. Digital gram scales improve epoxy accuracy across every epoxy project. Proper sanding ensures each epoxy coat bonds tightly to cured epoxy. Store unmixed epoxy resin and epoxy hardener between 70°F and 75°F. Verify whether your epoxy kit specifies volume or weight epoxy ratios. A thin epoxy seal coat stops wood pores from bubbling in epoxy. Warm water baths lower epoxy viscosity prior to blending epoxy batches. Every epoxy batch should be mixed slowly for full curing. Check epoxy studio temperature before pouring epoxy into a wood mold. Digital gram scales improve epoxy accuracy across every epoxy project. Proper sanding ensures each epoxy coat bonds tightly to cured epoxy. Store unmixed epoxy resin and epoxy hardener between 70°F and 75°F. Verify whether your epoxy kit specifies volume or weight epoxy ratios. A thin epoxy seal coat stops wood pores from bubbling in epoxy. Warm water baths lower epoxy viscosity prior to blending epoxy batches. Every epoxy batch should be mixed slowly for full curing. Check epoxy studio temperature before pouring epoxy into a wood mold. Digital gram scales improve epoxy accuracy across every epoxy project. Proper sanding ensures each epoxy coat bonds tightly to cured epoxy. Store unmixed epoxy resin and epoxy hardener between 70°F and 75°F. Verify whether your epoxy kit specifies volume or weight epoxy ratios. A thin epoxy seal coat stops wood pores from bubbling in epoxy. Warm water baths lower epoxy viscosity prior to blending epoxy batches. Every epoxy batch should be mixed slowly for full curing. Check epoxy studio temperature before pouring epoxy into a wood mold.
Deep Pour & River Table Frequently Asked Questions
How much epoxy do I need for a 6-foot river table?
A typical 72" × 36" dining table with an average 9-inch wide river channel and 1.75-inch thick black walnut slabs requires approximately 5.4 to 6.0 US gallons (690 to 770 fl oz) of deep pour casting resin once you account for live-edge bevel cavities and initial timber sealing.
What is the difference between 1:1 tabletop resin and 2:1 or 3:1 deep pour resin?
Tabletop resin (1:1 mix ratio) has a high viscosity (similar to honey) and cures fast, making it ideal for 1/8-inch surface coats but dangerous for thick pours above 1/4 inch. Deep pour casting resin (typically 2:1 or 3:1 mix ratio) has a water-thin viscosity that lets micro-bubbles escape easily and cures slowly over 48 to 72 hours so thick 2-inch pours do not overheat, crack, or turn amber.
How long does deep pour epoxy take to cure before flattening on a CNC or router sled?
Most 2:1 slow-cure systems reach tack-free gel stage in 24 to 36 hours at 72°F (22°C), demold strength in 72 hours, and full mechanical hardness for router sled flattening and orbital sanding after 5 to 7 days.
Should I brush a seal coat onto live edges before pouring the river?
Yes. Porous hardwood edges (especially oak, walnut sapwood, and spalted maple) trap air inside wood fibers. Brushing a thin seal coat of fast-cure resin onto the inner river walls 6 hours before your main deep pour prevents continuous bubble streams from rising into the clear channel.