Easy Epoxy Calc

How much epoxy for an 8 ft river table?

Short answer

You need about 9.43 gallons of mixed epoxy for an 8 ft river table with a 96-inch river averaging 10 inches wide on 2-inch slabs — 8.57 gallons for the channel, poured 1/16 inch proud, plus a 10% waste allowance.

How to work it out

  1. 96 in × 10 in × (2 in + 1/16 in proud) = 1,980 cu in = 8.57 gal
  2. + 10% waste = 9.43 gal → 4 × 3 gal kits
  3. Lifts: 2-1/16 in ÷ 2 in per layer → 2 lifts of 1-1/32 in and 4.71 gal each
  4. Batches: 4.71 gal per lift ÷ 1.5 gal max → 4 per lift × 2 lifts → A 3.14 qt (7.54 lb) + B 1.57 qt (3.18 lb) each
  5. Mix ratio 2 : 1 by volume, SG A 1.15 / B 0.97 (typical, not published by the maker — type your data sheet’s SGs for exact weights) → Part A 6.29 gal (60.3 lb) + Part B 3.14 gal (25.4 lb)

At 8 ft (96 in) long and 2 in thick, this is a big pour: the river holds 1,920 cubic inches at slab depth and 1,980 with the 1/16 in poured proud — 8.57 gallons before waste. Tables this long usually seat eight to ten, and the slabs are often sawn thicker and flattened down to 2 in before the pour.

Adjust for your project

in
in
Measure across the gap, not the whole table — the diagram just below the calculator shows where.
in
Your slab thickness at the thickest spot. About 1/16 in extra, so you can sand it flat, is added for you (“Pour proud” under More options). Many deep-pour resins also have a minimum depth — often 2 in.
in
On the label as “max pour depth”. Not bought yet? Leave 2 in — many deep-pour epoxies allow 1–2 in per layer.
Total of both bottles together. Most “1 gallon kits” are ½ gal resin + ½ gal hardener — enter 1. If the listing says 1 gal of EACH, enter 2.
More options: waste · proud · product …
%
Cup and bucket film, small leaks, the seal coat on the live edges. Use 15% for very open or punky wood.
in
Resin poured above the wood so the whole top can be sanded flat — 1/16 in is typical. Enter 0 if you already added it to the depth.
Fills in the mix ratio, weights and depth limits from the maker’s published data, and hides those fields. Always check the data sheet that comes with your batch.
in
From the label — e.g. MAS Deep Pour X 2 in, FlowCast 1/2 in
gal
Some labels lower the deepest layer for big pours, or cap the volume per layer. Enter that volume here; leave blank if your label doesn’t.
fl oz
Open knots and cracks that join the river fill up too. A rough guess is fine: a 1 × 1 × 3 in knot holds about 1.7 fl oz.
Only changes the Part A / Part B split — it’s printed on the kit. Tabletop and art resins are usually 1:1; deep pour often 2:1.
From the TDS, in g/ml. Leave blank for 1.15 (typical, not published by the maker).
From the TDS, in g/ml. Leave blank for 0.95 on 1:1 kits or 0.97 on other ratios (typical, not published by the maker).
gal
Resin + hardener mixed in one bucket. Leave blank to mix one whole kit at a time; enter less (1.5 gal or 6 L is easy with a drill paddle) to split each lift into batches you pour back to back.
From the label: when the next layer can go on (the recoat window) at room temperature. Leave blank to skip the pour schedule.
From the label: how long after the last pour before the table can come out of the form.
$
Optional — your kit price, for a cost estimate
Deep-pour epoxy to buy9.43 gal37.7 qt · 35.7 L
In short
Buy 4 × 3 gal deep-pour kits. Pour the river in two layers of about 1-1/32 in, mixing four batches for each.
Pours (lifts) needed
2 pours
Depth of each lift
1-1/32 in
Mixed epoxy per lift
4.71 gal (18.9 qt · 17.8 L)
What the resin will weigh in the table (for the form and legs)
78.7 lb (35.7 kg)
Left over from the last kit
2.57 gal (10.3 qt · 9.73 L)
Mixing details: batches, Part A and Part B
Mixing details: batches, Part A and Part B
Part A (resin)Part B (hardener)
Each batch (8 in all, 4 per lift)3.14 qt · 7.54 lb1.57 qt · 3.18 lb
Whole job6.29 gal · 60.3 lb3.14 gal · 25.4 lb
  • What to buy: 4 × 3 gal deep-pour epoxy kits. Each kit has both bottles (resin + hardener) — you don’t buy them separately.
  • Check the label’s minimum depth too. Many deep-pour resins list a minimum pour as well as a maximum — MAS Deep Pour X, for one, wants at least 2 in, and thinner pours cure slowly or stay soft. At 1-1/32 in per lift, choose a resin whose range includes that depth, and type its minimum under Min depth per pour (More options) to check.
  • Your depth is more than one pour can handle — plan 2 lifts of about 1-1/32 in, letting each reach the label’s recoat window before the next. The depth limit set this: 2-1/16 in ÷ 2 in per layer, rounded up.
  • Only the 1/16 in you pour proud takes this past 2 in — the slabs themselves are 2 in. If your label has headroom (check the data sheet), one pour to the slab tops plus a thin top-up later also works.
  • Mix 4 batches of about 1.18 gal for each lift and pour them back to back into the same layer, before they start to thicken. Some labels also cap the mass per pour — check yours.
  • Seal the live edges and any bark with a thin coat first — dry wood soaks up epoxy and releases bubbles into the pour.
  • About 2.57 gal will be left in the jugs. Kept sealed, it fills knots and cracks later, or makes a practice river board.

For this job · affiliate link
Deep pour epoxy, 3-gallon-plus kitYou need 9.43 gal — 4 × 3 gal kits. Bigger deep-pour kits are usually cheaper per gallon than a stack of small ones. Pick one whose label range includes 1-1/32 in per pour — the minimum as well as the maximum.
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Pours needed by the epoxy’s deepest layer (8 ft river, 10 in wide, 2 in slabs)

Pours needed by the epoxy’s deepest layer (8 ft river, 10 in wide, 2 in slabs)
Deepest layer allowed (from the label)Pours (lifts) neededDepth of each liftMixed epoxy per lift
1 in3 pours11/16 in3.14 gal
1.5 in2 pours1-1/32 in4.71 gal
2 in2 pours1-1/32 in4.71 gal
3 in1 pour2-1/16 in9.43 gal

What to know about an 8 ft river table

One lift or two? Two inches is exactly where deep-pour labels start to disagree. With the calculator’s default 2 in limit, the 1/16 in you pour proud takes the pour to 2 1/16 in, so it plans two lifts of about 1 1/32 in and 4.71 gallons each. MAS Deep Pour X is rated for 2–3 in per pour, so it takes this in one; a product rated for 1 in needs three lifts of about 3.14 gallons. The table above shows the count for each label rating, and the calculator’s note tells you when only the flattening allowance is forcing the extra lift.

Temperature. A pour this size can take several days to harden in a cold garage. Epoxyworks gives a general rule of thumb: cure time roughly doubles for every 18°F (10°C) drop in temperature. MAS asks for materials and shop to stay between 60 and 80°F throughout a Deep Pour X casting. If you can’t hold that for the whole cure, wait for warmer weather rather than heating the resin to compensate — an overheated deep pour is how you get cracks and yellowing. Enter the label’s recoat and demold hours to see the whole schedule, then run them through the cure time calculator for a cold shop.

Kits and handling. 9.43 gallons is four 3-gallon kits or two 6-gallon kits, and either way about 2.57 gallons is left over. The finished river holds about 78.7 lb of resin, so the form needs a flat, rigid base along the full 96 in — a sheet of melamine sagging between two sawhorses gives you a river that is thicker in the middle than at the ends.

The next size down is How much epoxy for a 7 ft river table. Working in metric? How much epoxy for a 200 cm river table covers a 2 m table on 5 cm slabs.

Different size? Use the full River Table Epoxy Calculator.

What you’ll need

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Frequently asked questions

How much epoxy for an 8 ft river table with a 12 inch river?

About 11.3 gallons with 10% waste (10.3 gal of channel) — 4 kits of 3 gal.

How many 6 gallon kits for an 8 ft river table?

2 kits of 6 gal cover the 9.43 gal, leaving 2.57 gal over.

Can MAS Deep Pour X fill an 8 ft river table in one pour?

Yes — 1 pour. MAS rates it for 2–3 in per pour, and 2 in slabs plus 1/16 in poured proud sit inside that range. You still need 9.43 gal, mixed in 7 batches if 1.5 gal is your largest.

How much epoxy for an 8 ft river table at 1.5 inches thick?

About 7.14 gallons for a 10 in river (6.49 gal of channel plus 10%).

Other common sizes

Sources