Bar top epoxy calculator

A plain bar top is just a flood coat (the thick, self-levelling top layer). The extra resin comes from the edges — what coats them and what drips off — and, if you’re embedding pennies, bottle caps or photos, from the fill pour that buries them, which usually goes on in several layers.

What the bar top calculator adds up

The total is up to four parts: the flood coat over the top, the edges — a thin film that stays on each coated edge plus the resin that drips off it and is lost — an optional fill pour that buries embedded items, and an optional seal coat on bare wood. Drips are worked out from the length of edge the resin runs over, not as a percentage of the top, so a long, narrow bar loses more for its size than a wide one. The waste allowance is only for what stays in the bucket and on the spreader.

top area = length × depth
flood coat = top area × coat thickness × coats
edge film = coated edge length × edge thickness × 1/32 in × coats
drips = coated edge length × 1.25 fl oz per ft × (coat thickness ÷ 1/8 in) × coats
fill depth = tallest item + 1/8 in, rounded up to 1/16 in (unless you enter one)
fill = fill area × (fill depth − share covered × item thickness)
total = (flood + edge film + drips + fill) × (1 + waste) + seal coat

An 8 ft bar that is 24 in deep has 16 sq ft of top. A single 1/8 in flood coat over that is about 1.25 gallons — the same figure you get from TotalBoat’s published coverage for its TableTop epoxy, about 12.8 sq ft per gallon at 1/8 in. With the front and both ends coated (12 ft of edge, 1.5 in thick), the edge film adds about 3.7 fl oz, the drips 15 fl oz, and 5% for the bucket brings it to about 1.46 gallons — two 1-gallon kits. A shallower 20 in bar is worked through in how much epoxy for an 8 ft bar top.

Bottle caps, pennies and photos

Embedded bar tops need a dam or raised rail around the edge to hold the fill pour, so no drips are counted for the fill unless you say your fill layers run over the edges. The fill depth is your tallest item plus about 1/8 in (3 mm) of clear cover: the calculator fills that in for you — 3/16 in over pennies, 3/8 in over bottle caps — and resets it whenever you change the items, or you can type your own. A depth that doesn’t bury the items is flagged, never quietly dropped from the total. If the items fill only one panel or band, enter that area and the fill is worked out for it alone. Solid items take up room in the fill, so the calculator subtracts them: a current US penny is 0.0598 in (1.52 mm) thick, and nested edge to edge pennies cover about 90.7% of the top; bottle caps laid open side down trap air, so each acts as a solid 1/4 in disc covering about 78.5% of the top in straight rows. Caps laid open side up fill with resin and save nothing. Photos and cards take up no room at all.

Tabletop epoxies usually have to go on in layers — TotalBoat, for one, caps its TableTop at 1/4 in per coat — so a deep fill means several pours with a recoat window between them. The calculator shows the layer count. See how much epoxy for a penny bar top and how much epoxy for a bottle cap bar top for the same 8 ft bar with each kind of fill.

Seal coat on bare wood

Bare wood is full of air. Poured straight onto it, a flood coat pulls that air up as bubbles for the first hour or so. A seal coat is a thin first coat brushed or scraped into the wood the day before. The calculator uses about 1 fl oz per sq ft (0.32 L/m²) for closed-grain or already flat wood, 2 fl oz (0.64 L/m²) for open grain such as oak, ash or walnut, and 4 fl oz (1.3 L/m²) for spalted, burl or end grain, over the top and the coated edges, plus 5% for the cup and brush.

Tips

• Seal paper items (photos, labels, cards) with a thin coat of epoxy or a sealer first, or they can darken where resin soaks in.
• Glue coins and caps down so they don’t float or shift.
• Finish with a full flood coat over the fill layers — it gives a single, even surface.
• On long bars, mix in several batches and pour them back to back into the same layer, working from one end so the wet edges merge. A full bucket of mixed epoxy heats up and shortens its own working time, so don’t mix more than you can pour promptly — the batch figure under More options splits the job for you.
• Keep hot pans off the finished bar. ArtResin, for example, rates its cured resin to about 120°F.