How Much Epoxy for a River Table or Deep Pour (Lifts, Pours & Wait Times)
Deep pour epoxy cures via an exothermic reaction — why depths over about 2 inches need multiple lifts, not one big pour.
Deep pour epoxy cures via an exothermic reaction — too much mass at once traps heat, which can crack, cloud, or yellow the cure. Depths over about 2 in typically need to be split into multiple lifts, with a 24–36 hr wait between each. The calculator handles the volume math for rectangle, round, or river-table shapes; the lift count is guidance you plan around it.
How to read the inputs
Mold Shape
- Rectangle, round, or river table — each shape asks for the dimensions it actually needs
River Table Dimensions
- Table length and width, plus both slab widths — the calculator subtracts the slabs from the width to estimate the river gap
Pour Depth, Total
- Your full intended depth — past about 2 in, plan multiple lifts rather than one pour (see the FAQs)
Waste / Overage Allowance
- Defaults to 0% — the app’s own guidance is 5–10% is typical for mixing residue and mold seepage
Worked example
A river table: 84 in long, 36 in table width, with 15 in and 14 in slabs — river gap = 36 − 15 − 14 = 7 in. Footprint = 84 × 7 = 588 in². Poured 3 in deep: volume = 588 × 3 = 1,764 in³, or 1,764 ÷ 231 = 7.64 gal raw. With a 10% waste allowance: 8.40 gal total to order. At 3 in deep — over the roughly 2 in single-pour threshold — this pour needs 2 lifts of about 1.5 in each, not one shot.
Try it with your own mold
Pick your shape and enter its dimensions plus pour depth — waste defaults to 0%, so dial in 5–10% yourself.
Full result gives total gallons, quarts, fl oz, and liters to order.
Open the live calculator →Common mistakes
- Pouring the full depth in one shot past about 2 in — the single most common way to crack, cloud, or yellow a river table
- Not waiting long enough between lifts — 24–36 hours is typical, longer in cool ambient temperatures
- Using a standard fast hardener instead of a slow or extra-slow one rated for thick sections
- Treating the river gap estimate as exact for a wavy live edge — measure at a few points along the river and average them
Deep pour resin is one of the most ratio-sensitive products on the site — see epoxy mixing ratios explained before you mix a batch.
Frequently Asked Questions
Why can’t I just pour a deep river table in one shot?
Deep pour epoxy cures via an exothermic reaction — too much mass at once traps heat, which can cause cracking, cloudiness, or yellowing as it cures. That’s why depths over about 2 inches typically get split into multiple lifts instead of one pour.
How long do I wait between lifts?
24–36 hours is the typical range, depending on the product and ambient temperature — check your product’s TDS. Some installers use an infrared thermometer to confirm the previous lift has cooled below roughly 85°F before pouring the next.
Do I need a special hardener for a deep pour?
Yes — deep pour products use a slow or extra-slow hardener engineered for a lower rate of heat buildup. A standard fast epoxy hardener is not rated safe for thick sections.
How accurate is the river gap estimate for a live-edge slab?
It’s a straight-line estimate from your two slab widths. For a wavy live edge, measure the actual gap at a few points along the river and average them for a more accurate number.