How this deep pour calculator works
Deep pour resins have a maximum depth per pour — exceed it and the curing reaction generates enough heat to yellow, crack or even smoke. The calculator takes your total casting depth, divides it by your resin's rated maximum, and returns the number of layers along with the total and per-layer volume, including overage for what stays in the mixing bucket.
Know your resin's rating
Ratings vary widely: standard tabletop epoxy manages about ¼ inch (6 mm) per pour, common deep pour products are rated 2 inches (5 cm), and specialist casting resins go to 4 inches (10 cm) or more in a single pour. The rating also depends on volume — a narrow channel dissipates heat better than a big block — so treat the label figure as the ceiling, not a target, on large castings.
Pouring in layers
Pour the next layer when the previous one has gelled but is still tacky — usually within the recoat window on the label (often 24–48 hours for deep pour). Within that window, layers bond chemically with no sanding. Miss it and you'll need to scuff-sand the surface for mechanical adhesion. Keep the workshop temperature steady; cold slows cure dramatically and heat accelerates it.
Controlling heat on big pours
For large castings near the depth limit: pour in a cool room (65–72°F / 18–22°C), use a fan across the mold surface, and never leave a fresh deep pour in direct sun. If the resin starts smoking or the mold gets too hot to touch, it has run away — there's no saving that pour, but a fan can protect the wood around it.