Easy Epoxy Calc

How much epoxy for a seal coat on a 6 ft wood slab?

Short answer

A seal coat on a 6 ft live-edge slab (72 in long, averaging 36 in wide) takes about 0.33 gallons of epoxy on open-grained wood such as walnut or oak — 2 fl oz per square foot over 18 square feet of face plus the sides. With a 1/8 inch flood coat on top, the whole job is 2.04 gallons.

How to work it out

  1. Average width: (34 in + 38 in + 36 in) ÷ 3 = 36 in
  2. Top: 72 in × average width 36 in = 2,592 sq in (18 sq ft)
  3. 18 sq ft × 1/8 in × 1 coat = 324 cu in = 1.4 gal
  4. Edge length: ≈ 2 × (length + average width) = 216 in (18 ft)
  5. Drips: 18 ft × 1.25 fl oz/ft × 1 coat = 22.5 fl oz
  6. Film on the sides: 216 in × 1.5 in × 1/32 in × 1 coat = 5.61 fl oz
  7. (1.4 gal + 22.5 fl oz + 5.61 fl oz) × (1 + 5% bucket/other) = 1.7 gal
  8. Seal coat: (18 sq ft + 2.25 sq ft of sides (18 ft × 1.5 in)) × 2 fl oz/sq ft × 1.05 = 0.33 gal
  9. 1.7 gal + 0.33 gal seal = 2.04 gal → 3 × 1 gal kits
  10. Batches: 1.7 gal per coat ÷ 1 gal → 2 per coat, each A 1.7 qt (4.09 lb) + B 1.7 qt (3.38 lb)
  11. Mix ratio 1 : 1 by volume, SG A 1.15 / B 0.95 (typical, not published by the maker — type your data sheet’s SGs for exact weights) → Part A 1.02 gal (9.77 lb) + Part B 1.02 gal (8.07 lb)

A seal coat is brushed or scraped on thin to close the grain before the flood coat, so air escaping from the wood doesn’t leave bubbles in the finish. How much it takes depends on the wood, not the thickness of a pour: about 1 fl oz per square foot on closed grain, 2 on open grain and 4 on spalted or burl wood. This slab was measured at three spots — 34, 38 and 36 in — which the calculator averages to 36 in.

Adjust for your project

in
Measure the top surface only — drips over the edges are covered by the extra allowance.
in
Measure across the top face, bark edge to bark edge, at 3–5 evenly spaced spots. The calculator averages them.
in
in
in
in
Leave at 1/8 in unless your epoxy’s label says otherwise.
1 is normal. Use 2 for extra depth or to bury bottle caps or photos.
A thin first coat brushed or scraped into bare wood, so air in the grain doesn’t bubble up into the clear coat.
gal
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: edges · edge · waste …
Most tops are poured so the epoxy runs over and coats the sides. A tape dam keeps it on the top only.
in
How tall the edge is — usually the thickness of the top.
%
Bucket and cup residue and other small losses. Edge drips are worked out separately from the edge length.
Fills in the mix ratio, weights and depth limits from the maker’s published data. Always check the data sheet that comes with your batch.
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. Big batches heat up and thicken sooner, so pros mix the next one while the last is being poured.
$
Optional — your kit price, for a cost estimate
Tabletop epoxy to buy2.04 gal8.14 qt · 7.71 L
Kits to buy
3 kits
Clear coat(s) on the top
1.4 gal (5.61 qt · 5.31 L)
Runs off the edges (drips)
22.5 fl oz (0.7 qt · 0.67 L)
Film left on the sides
5.61 fl oz (0.18 qt · 0.17 L)
Seal coat (mixed separately)
0.33 gal (1.33 qt · 1.26 L)
Surface area
18 sq ft
Average width
36 in
Batches to mix (clear coats)
2 batches
Per batch (volume, then weight)
A 1.7 qt (4.09 lb) + B 1.7 qt (3.38 lb)
When mixing — Part A (resin)
1.02 gal (4.07 qt · 3.85 L)
When mixing — Part B (hardener)
1.02 gal (4.07 qt · 3.85 L)
Part A by weight
9.77 lb (156 oz · 4.43 kg)
Part B by weight
8.07 lb (129 oz · 3.66 kg)
Left over from the last kit
0.96 gal (3.86 qt · 3.65 L)
  • What to buy: 3 × 1 gal tabletop epoxy kits. Each kit has both bottles (resin + hardener) — you don’t buy them separately. Looking at a different kit size? Change Kit size above.
  • Mix the seal coat (0.33 gal) as its own small batch, brush or scrape it into the grain, and pour the clear coat inside the label’s recoat window.
  • Each coat is 2 batches. Mix the next one while the last is being spread and pour them back to back, so the wet edges merge before they start to thicken.

For this job · affiliate link
Tabletop / bar top epoxy kitYou need 2.04 gal; 3 × 1 gal kits leaves 0.96 gal over, so topping up with a smaller kit may be cheaper — compare kit sizes. Self-leveling tabletop epoxy is made for 1/8 in coats; a deep-pour resin would run off the edges for days.
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Seal coat for this slab by type of wood (your measurements)

Seal coat for this slab by type of wood (your measurements)
WoodSeal coat (mixed separately)Tabletop epoxy to buyKits to buy
Closed grain (maple, cherry)21.3 fl oz1.87 gal2 kits
Open grain (oak, ash, walnut)0.33 gal2.04 gal3 kits
Spalted, burl, end grain0.66 gal2.37 gal3 kits

What to know about seal-coating a 6 ft slab

On this slab the seal coat is 0.33 gallons at the open-grain rate, with the 1.5 in sides included and 5% for the cup and brush. Closed-grain maple or cherry takes about 21.3 fl oz; spalted, burl or punky wood takes about 0.66 gallons for one coat and often needs a second. Pouring a 1/16 in flood as a “seal” uses far more than any of these and still leaves a thin coat that won’t level, so brush or scrape it instead.

Measure a live-edge slab at several spots. The face narrows and widens along its length, and one measurement at the widest point overstates the area. Choose Live-edge slab in the calculator, enter the length and three to five widths, and it uses the average for the face and 2 × (length + average width) for the edge.

Fill the voids before you seal. Knots, cracks and bark inclusions on a live-edge slab can swallow far more resin than the face itself; tape their undersides, fill them with a deep-pour or gap-filling epoxy, and only then seal the whole face.

Mix the seal coat as its own small batch. Work it into the grain with a brush or spreader and go back over patches that look dry — those are the pores that would otherwise let air up through the flood coat. TotalBoat tells you to seal-coat wood and other porous surfaces before flood coating, and to wait at least 3 hours at 70°F before the next coat; follow your own label’s recoat window.

Once sealed, the flood coat for a planed top this size is on How much epoxy for a 6 ft dining table; for a longer table, see How much epoxy for an 8 ft table.

Different size? Use the full Tabletop Epoxy Calculator.

What you’ll need

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Frequently asked questions

How much seal coat epoxy for a closed-grain 6 ft slab?

About 21.3 fluid ounces at 1 fl oz per square foot — closed-grain woods such as maple or cherry soak up about half what oak or ash does. With the flood coat, 1.87 gallons in all.

How much epoxy to seal coat an 8 ft live-edge slab?

About 0.44 gallons on open grain over 24 square feet at the same widths — 2.68 gallons with the flood coat, or 3 kits of 1 gallon.

How much epoxy to seal coat a spalted or burl 6 ft slab?

Allow about 0.66 gallons for one coat at 4 fl oz per square foot — soft, punky areas keep absorbing resin, and many slabs like this need a second seal coat.

Other common sizes

Sources