EngineerBenchCalculating a two-part resin mix
A resin ratio specifies the proportion of part A to part B. First choose whether the manufacturer's ratio is by mass or by volume, then enter the required batch amount. A 2:1 ratio means two matching units of A for each unit of B, not two units added to an already measured total.
Do not exchange mass and volume ratios
Components can have different densities, so a ratio specified by weight is not automatically valid in measuring cups. Use the product's stated basis. An extra-material allowance increases the required amount of both components without changing their ratio.
Batch size also affects handling
The entered batch limit is a check against your chosen limit, not a prediction of heat generation or pot life. Follow the product's instructions for maximum mix size, container, temperature, protective equipment, and working time. A correct ratio alone does not establish a safe mixing process.
Splitting a total into two components
For a 300 g batch at a 2:1 mass ratio, there are three ratio parts in total. Part A is 200 g and part B is 100 g. If the target quantity already includes extra material for losses, do not apply the extra allowance again. The ratio must remain unchanged as the total batch grows or shrinks.
For a volume-based product, perform the same proportional split in volume units, using the manufacturer's stated ratio. Converting a finished total from volume to mass requires appropriate component density information; it cannot be inferred from the ratio alone. Use a scale or measuring vessel with resolution suitable for the smaller component, since its relative error can dominate a small batch. Mix and handle the product according to its instructions. A computed quantity is not a prediction of cure quality, exotherm, ventilation needs, or safe working time. If the planned batch exceeds the entered limit, divide the work into appropriate batches without changing the component proportion.
Formula
A = total × A-parts/(A-parts+B-parts); B = total − A. Follow the supplier’s batch-size and pot-life limits.