Deep Pour Epoxy Calculator

Why One Deep Layer Doesn't Work

Epoxy cures through an exothermic reaction — it generates its own heat as it sets. In a thin layer, that heat dissipates into the air fast enough to stay harmless. Pour several inches at once and the heat has nowhere to go: the center of the pour can climb well past what the resin is rated for, causing cracking, cloudiness, yellowing, or in bad cases visible smoking and a ruined piece. Deep pour epoxy is formulated to run cooler than standard casting resin, which is why it can go thicker than the usual 1/2 inch limit — but even deep pour formulas have a ceiling, and it's almost always lower for every layer after the first.

How to Use This Calculator

Enter your mold's length and width, and the total depth you need to fill. Check your specific product's instructions for its maximum single-pour depth (commonly 1-2 inches for the first pour) and its maximum depth for additional layers poured on top of a cured one (commonly around 1 inch) — brands vary, so use your product's numbers rather than the defaults if the label says otherwise.

How We Calculate Your Pour Schedule

The first pour fills up to your first-pour max depth (or your full total depth, if that's shallower). Any remaining depth is then split into additional layers, each up to your later-pour max depth, with the final layer taking whatever is left over. For each layer, volume (cubic inches) = length × width × that layer's depth. We add your waste buffer, convert to fluid ounces (÷ 1.80469), then split resin and hardener by your mix ratio — for a 2:1 ratio, resin gets 2/3 of that layer's total and hardener gets 1/3.

Example: A 3-Inch River Table

Say you're filling a 24" × 12" mold to a total depth of 3", with a 2" first-pour max and a 1" max for later layers. That's two pours: a 2" first pour, then a 1" second pour. At a 2:1 ratio with a 10% waste buffer, the first pour needs about 351 fl oz total (234 oz resin + 117 oz hardener), and the second needs about 176 fl oz total (117 oz resin + 59 oz hardener) — roughly 4 gallons combined, which is typical for a tabletop-sized deep pour.

Cure Time Between Layers Isn't Fixed

This tells you the depth and volume for each layer, not how long to wait between them — that depends on your product and room temperature, but 12+ hours between layers (enough for the previous one to gel firm but not fully cure) is a common starting point on deep pour product labels. Always check your specific product's data sheet for its actual maximum pour depths and recoat window; going by a generic default when your product's label says otherwise is exactly the mistake that causes overheating.