Quick answer: use tabletop (coating) epoxy for thin layers, typically around ⅛ inch, such as bar tops, tables and art pieces. Use deep pour (casting) epoxy for thick castings of roughly an inch or more, such as river tables and large moulds. The difference is how fast each one cures and how much heat it gives off.
Side by side
|
Tabletop epoxy |
Deep pour epoxy |
| Typical layer |
About ⅛ in (3 mm) |
Often 1 to 4 in, depending on product |
| Thickness of mix |
Thicker, self-levels in thin coats |
Thin and runny, flows into gaps |
| Working time |
Shorter |
Much longer |
| Cure before handling |
Often about a day |
Often several days |
| Heat during cure |
Higher per volume |
Low, designed for mass |
| Common mix ratio |
Often 1:1 by volume |
Often 2:1 or 3:1 by volume |
| Best for |
Coatings, flood coats, art |
River tables, castings, deep moulds |
Every product is different, so always check the label for the maximum layer, cure time and ratio.
Why thickness matters: heat
Epoxy cures through a chemical reaction that gives off heat. In a thin layer, that heat escapes easily. In a thick pour, it builds up, which speeds up the reaction, which creates more heat.
Pour tabletop epoxy too thick and it can get hot enough to crack, yellow, smoke, or cure with ripples. Deep pour epoxy is formulated to react slowly so the heat has time to escape.
How thick to pour
Tabletop epoxy: pour in layers around ⅛ inch. For a thicker look, add more layers once the previous one has cured enough, following the recoat window on the label.
Deep pour epoxy: pour up to the stated maximum depth per layer. Room temperature matters: warmer rooms speed up curing and can lower the safe depth.
Can you use them together?
Yes, and many river tables do. A common approach:
- Seal coat of tabletop epoxy over the wood edges
- Deep pour epoxy for the river itself
- Flood coat of tabletop epoxy over the whole surface for a hard, glossy finish
Calculate each layer separately with the epoxy resin calculator. Set the depth to each layer's thickness.
Cost
Per gallon, the two are often similarly priced, but deep pours use far more volume. A tabletop flood coat on a 48 × 30 inch table needs under a gallon; a river in the same table could need four or more.
Choosing quickly
- Coating a surface? Tabletop.
- Filling a gap, mould or river thicker than about ½ inch? Deep pour.
- Not sure? Check the thickest point of your pour against each product's maximum depth.
Matching the epoxy to the project
| Project |
Typical depth |
Best choice |
| Bar top or table flood coat |
About ⅛ in |
Tabletop |
| Coasters in a silicone mould |
¼ to ½ in |
Tabletop in two layers, or a casting resin rated for that depth |
| Serving tray coat |
⅛ to ¼ in |
Tabletop |
| River table |
1 to 2 in or more |
Deep pour, then a tabletop flood coat |
| Large resin casting or block |
2 in or more |
Deep pour, in layers if needed |
| Filling knots and cracks |
Varies |
Tabletop for small voids, deep pour for large ones |
How temperature changes everything
Epoxy reacts faster when it's warm. A room at 85°F (29°C) can make a deep pour cure much hotter and faster than the same pour at 70°F (21°C), which lowers the safe pour depth. In a cold room, tabletop epoxy can stay tacky for longer and may cure cloudy.
Most manufacturers recommend working at moderate room temperature and keeping the resin at room temperature before mixing. If your workshop swings in temperature, choose the cooler time of day for deep pours.
Calculating each layer
Work out the volume for each layer separately in the epoxy resin calculator:
- Seal coat: a very thin layer, often about 1/16 inch, brushed onto raw wood.
- Deep pour: the river or casting, at the full depth or split into layers below the product's maximum.
- Flood coat: about ⅛ inch over the whole top.
Adding them together tells you how much of each product to buy. For a river table, see how much epoxy for a river table.
Signs you used the wrong type
- Cracks, yellowing or smoke during cure: tabletop epoxy poured too thick.
- Soft or tacky after the stated cure time: wrong mix ratio, poor mixing, or a cold room.
- Wavy or rippled surface on a thick pour: heat built up too fast.
- Bubbles throughout a deep pour: resin was mixed too vigorously, or the wood wasn't sealed and released air.
Safety basics
Work in a ventilated space, wear nitrile gloves and eye protection, and keep mixed resin away from skin. Never leave a large batch of mixed epoxy sitting in a deep cup, because it can heat up quickly in a concentrated mass.