Epoxy countertops and bar tops
A surface, not a casting. Everything about the job follows from the fact that a coating epoxy goes on an eighth of an inch at a time.
A coating epoxy is poured at about 1/8 in per flood coat, so a 10 ft kitchen counter takes roughly 6.8 litres for one coat plus wastage. Seal the substrate with a thin coat first to stop it outgassing bubbles into the flood coat, then pour the flood coat and let it self-level. Build depth with additional coats rather than one thick pour — going deeper in one go is a heat hazard rather than a slow cure.
A countertop is the clearest example of the difference between coating and casting. The resin is a surface here — a film a couple of millimetres thick over whatever is underneath — and everything about the job follows from that. Table top / coating epoxy goes on at 1/8 in per flood coat, sets hard in 72 hours, and self-levels well enough that a brush mark disappears while you watch.
The arithmetic is pure geometry and it is worth doing rather than guessing. A 21 square foot counter takes 6.8 litres for one flood coat including 10% wastage — 1.79 gal, or about $107 of resin. One US gallon covers 12.8 square feet at that depth; you will see 12 printed on tins, and the difference is about 6% of waste allowance already folded in.
What people underestimate is the preparation, not the pour. A porous substrate — bare wood, MDF, old laminate with a chip in it — releases air into the resin for hours, and the flood coat is where that air ends up. The seal coat is the whole difference between a glassy counter and one with a constellation of bubbles frozen into it. If you have not poured resin before, the beginner's guide covers the mixing this page assumes.
One flood coat, by size
Every row is 1/8 in deep, because that is what a coating epoxy pours at — only the area changes. Volumes include 10% wastage, and the cost is materials at $60 a gallon. A second coat doubles the resin and does not double the depth of the first.
The three coats, and what each one is for
Not about thickness. A thin coat brushed or squeegeed into the surface fills the pores and stops the substrate outgassing into the pour that matters. It will look patchy and imperfect and that is fine — nobody sees it. Skipping it is the commonest cause of a bubbly counter, and the one thing you cannot fix afterwards.
Poured on and left to find its own level, which it does well. Spread it roughly with a squeegee to get it near the edges, then stop touching it — self-levelling works better than you do. 6.8 litres on a 21 sq ft counter, and the 20–40 minutes of working time is the clock you are on.
A bar top is looked at from a foot away, so many get two. The second doubles the resin and does not double the depth of the first — and it wants to go on inside the recoat window, while the first is still tacky, or it needs a light sand to bond. The pour depth guide covers the timing.
What decides how it comes out
Every flood coat is 1/8 in whatever the surface. Pouring thicker to save a coat is the mistake this whole craft's safety page is about: the reaction is exothermic, the heat accelerates it, and a coating epoxy in a deep mass cracks and smokes. If you genuinely need thickness, that is deep pour / casting epoxy and a different job.
Wood, MDF, concrete and chipped laminate are all porous, and warm resin sitting on them draws air out for hours. The bubbles appear an hour into the cure, long after you have stopped watching. A seal coat closes the pores; so does warming the substrate slightly before the flood coat, so it is cooling rather than warming while the resin sits on it.
A self-levelling resin runs off every edge it can reach, and on a counter that is a lot of edge. Tape the underside of the overhang so the drips form a clean line you can trim rather than a fringe you have to sand, and put something disposable underneath — the runoff is real volume, and it is part of why the wastage allowance exists.
Resin finds the horizon, not the counter. A cabinet run that is 2 mm out casts a top that is 2 mm thicker at one end, and on a counter that shows as a visible pool. Shim and check with a long level before the seal coat, not after — once the flood coat is on, the only fix is more resin.
Around 21–24 °C is the working window. Cold resin holds bubbles and stays thick; warm resin sets before it has levelled. And a counter is a very large horizontal surface staying tacky for hours, so anything airborne lands in it — do not sand, sweep or run a fan in the room the day you pour.
Whether you can prepare food on it is a separate matter with a careful answer, and it is not a property of epoxy in general. The food safe guide covers what a manufacturer's claim actually means, what full cure has to do with it, and why a cutting surface is a different question from a counter.
Doing one
Area times 1/8 in, plus wastage, plus the runoff. The bar top flood coat, 8 ft on the table is 5.2 litres; a 21 sq ft counter is 6.8 litres. The calculator has presets for both and takes your own dimensions.
Brush a thin coat over everything the flood coat will touch, including the edges and any exposed end grain, and let it set. It takes half an hour and it is the difference between a clear top and a bubbly one.
6.8 litres of fast resin in a single container is a deep pour in its own right and can exotherm before it reaches the counter. Mix in wide vessels a few litres at a time, pour each one out immediately, and have the next one going while you spread.
Get it near the edges with a squeegee or a gloved hand and stop. Every additional pass adds air and disturbs a surface that is already levelling itself better than you can. Then torch the bubbles in one sweeping pass and cover it.
Resin will run around a square edge and set into a fringe of drips that has to be sanded off later. Tape a few millimetres below the edge and the runoff forms a clean line that peels away once cured.
Hard to the touch at 24 hours and fully cured at 72. Chemical resistance and hardness both arrive at full cure, not before — a mug set down on day two leaves a ring that is permanent.
Size your own top
Pick the countertop or bar top preset, put in your own length and width, and the calculator gives the volume per coat, the resin and hardener split and the cost at your own kit price.
Open the epoxy calculator →Print the pour-depth card
Maximum pour depth and cure windows by resin type — the number that cracks a casting. Free.
Estimates, not advice. Every figure on this page is computed from published reference values and standard measures, so your own inputs, equipment and conditions will move it. Nothing here is professional advice — talk to a qualified professional before acting on it.