Easy Epoxy Calc

How much epoxy for a 7 ft river table?

Short answer

You need about 7.25 gallons of mixed epoxy for a 7 ft river table with an 84-inch river averaging 10 inches wide on 1.75-inch slabs, including a 10% waste allowance. The 6.59 gallons that stays in the table weighs roughly 60.5 pounds.

How to work it out

  1. 84 in × 10 in × (1-3/4 in + 1/16 in proud) = 1,523 cu in = 6.59 gal
  2. + 10% waste = 7.25 gal → 3 × 3 gal kits
  3. Lifts: 1-13/16 in ÷ 2 in per layer → 1 lift
  4. Batches: 7.25 gal ÷ 1.5 gal max → 5 → A 3.87 qt (9.28 lb) + B 1.93 qt (3.91 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 4.83 gal (46.4 lb) + Part B 2.42 gal (19.6 lb)

Seven-foot (84 in) tables usually seat eight, and they are often built from thicker slabs — 1¾ in here — with a wider river to suit the scale. That puts the pour at around 7¼ gallons, which is more than anyone can mix thoroughly in one bucket.

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 buy7.25 gal29 qt · 27.4 L
In short
Buy 3 × 3 gal deep-pour kits. Pour the river in one layer, mixed in five batches.
What the resin will weigh in the table (for the form and legs)
60.5 lb (27.4 kg)
Left over from the last kit
1.75 gal (7 qt · 6.62 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 (5 in all)3.87 qt · 9.28 lb1.93 qt · 3.91 lb
Whole job4.83 gal · 46.4 lb2.42 gal · 19.6 lb
  • What to buy: 3 × 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 1-13/16 in, choose a resin whose range includes that depth, and type its minimum under Min depth per pour (More options) to check.
  • Mix 5 batches of about 1.45 gal 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 1.75 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 7.25 gal — 3 × 3 gal kits. Bigger deep-pour kits are usually cheaper per gallon than a stack of small ones. Pick one whose label range includes 1-13/16 in per pour — the minimum as well as the maximum.
View on Amazon (opens in a new tab)

7 ft river table epoxy by average river width (84 in long, 1.75 in slabs)

7 ft river table epoxy by average river width (84 in long, 1.75 in slabs)
Average river widthDeep-pour epoxy to buyKits to buyWhat the resin will weigh in the table (for the form and legs)
8 in5.8 gal2 kits48.4 lb
10 in7.25 gal3 kits60.5 lb
12 in8.7 gal3 kits72.6 lb
14 in10.2 gal4 kits84.7 lb

What to know about a 7 ft river table

Mix in batches. At a 1.5 gallon largest batch the calculator plans five batches of about 1.45 gallons, mixed one after another and poured into the same layer while the previous batch is still liquid. Deep-pour resins give you a long working time — MAS quotes about 12 hours for Deep Pour X — so there is no need to rush, but scrape the sides and bottom of the bucket every time. Resin that never met its hardener turns up later as soft, tacky streaks.

Heat builds in a bigger mass. Epoxy gives off heat as it cures (the exotherm), and a larger, thicker mass holds on to more of it. WEST SYSTEM warns that a cupful of mixed epoxy left in its container can get hot enough to melt the cup. Get each batch out of the bucket and into the form, where it spreads thin. At 1 13/16 in including the pour-proud allowance you are inside the per-pour limit of many deep-pour products but not all: if your label says 1 in, this becomes two lifts of about 3.63 gallons.

Kits and flatness. Three 3-gallon kits cover the 7.25 gallons with about 1.75 gallons spare. Before you pour, check the slabs and the form for twist: an 84 in slab that rocks by 1/8 in at one corner leaves a gap under the edge, and that is where the resin will leak out.

The next size down is How much epoxy for a 6 ft river table; for a longer build on 2 in slabs, see How much epoxy for an 8 ft river table.

Different size? Use the full River Table Epoxy Calculator.

What you’ll need

As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.

Frequently asked questions

How much epoxy for a 7 ft river table with a 12 inch river?

About 8.7 gallons with 10% waste — 3 kits of 3 gal, with only 0.3 gal spare. That is a tight fit; buy a fourth kit if the wood is bare or this is your first pour.

How much epoxy for a 7 ft river table 2 inches thick?

About 8.25 gallons for a 10 in river (7.5 gal of channel plus 10%), in 2 pours if your resin tops out at 2 in per layer.

How many pours for a 7 ft river table if the epoxy is rated for 1 inch?

2 pours of about 3.63 gal each, the second once the first reaches the label’s recoat window.

Other common sizes

Sources