How resin calculator Works
The volume math
Rectangular pours: length ร width ร depth = cubic inches; 1 cubic inch โ 0.554 fluid ounces. The calculator also handles the classic cylinder case implicitly โ for round molds, use width ร 0.785 as the effective width (ฯ/4). Add 5โ10% for resin that stays in the mixing cup and on the stir stick; the calculator bakes in 10%.
Ratio means your brand's ratio
Epoxy systems mix by volume (1:1 and 2:1 common) or by weight โ and the two are not interchangeable because part B's density differs from part A's. Follow your kit's printed ratio and its unit. Off-ratio resin never fully cures: sticky, bendy, or weeping surfaces are ratio errors, not bad luck.
Depth is a chemistry limit
- Coating pours (countertops, art): 1/8โ1/4 inch per coat โ the calculator's default depth.
- Casting resins go deeper (1โ2 inches+) but generate heat; thick pours in coating resin overheat, crack yellow, and can smoke. Deep molds need casting-grade resin and, often, layered pours.
- Layer rules: let each layer gel to the manufacturer's window before the next โ too soon traps bubbles, too late shows a seam line.