Deep-pour layer planner

Why pours have a depth limit

Epoxy cures by a chemical reaction that gives off heat. West System explains that the larger or thicker the mass of mixed epoxy, the more heat it generates, and that a 100 g mass can reach 400 °F in a mixing pot (West System). A deep-pour resin is formulated to react slowly enough that a thick layer stays under control, but only up to a thickness the manufacturer has tested. TotalBoat lists bubbling, smoking, shrinking and cracking as the results of pouring deeper than recommended (TotalBoat).

That limit is printed on most deep-pour data sheets as a maximum depth or thickness per pour. This planner reads it from our product database and does the division for you.

Formula and assumptions

n = ⌈ T ÷ t_max ⌉    layer = T ÷ n    start of layer k = (k − 1) × w_min

• T is the total thickness you want to build.
• t_max is the maximum depth per pour from the product’s data sheet. If the data sheet does not publish one, the planner does not guess; choose “Enter values from my own data sheet” and type the value from your label.
• n is rounded up, because a partial layer is still a pour.
• Equal layers split the thickness evenly. The table also shows the other common approach, full layers at the maximum with the remainder last, so you can pick what suits your project.
• w_min is the minimum wait between pours from the data sheet. Some products publish a window instead (a minimum and a maximum); the planner shows both.

Two things the planner deliberately does not do. It does not adjust the depth limit or the wait for your shop temperature, because data sheets state the conditions their numbers apply to and we do not extrapolate beyond them. It also does not pick the product for you: products differ in viscosity, clarity and cure speed, not only depth.

Some data sheets give more than one limit, for example a deeper limit for small castings and a shallower one for large slab pours. The product page shows the full wording; for river tables, use the slab figure. When the stored limit is the strictest one the documents give, the planner uses it. When the documents also give a smaller limit for some applications, the planner does not choose between them; it asks you to enter the limit that fits your project.

Worked example

A river table needs 3 in of resin. The chosen product’s data sheet allows 2 in per pour and asks for at least 24 hours between pours.

1. Layers: 3 ÷ 2 = 1.5, rounded up to 2 pours.
2. Equal split: 1.5 in each. Full-first split: 2 in, then 1 in.
3. Earliest start of the second pour: 24 hours after the first.

If the same project used a product limited to 1 in per pour, it would need 3 pours and at least 48 hours before the last one could start, which is why the depth limit often decides the schedule of a build.

Reading the result

• “Not published” in the wait row means the data sheet does not state a minimum time between pours. Check the manufacturer’s instructions or ask them before you plan the second pour.
• A warning appears when a product publishes a minimum pour thickness and one of your layers would be thinner than it.
• The drawing shows the layers to scale relative to each other. It is a section through the river, not a plan view.