Why Resin Mixing Ratios Cannot Be Guessed

For a multi-component resin, the mixing ratio belongs to the specific product. Guessing it, or changing it to make the material cure faster, can prevent the system from behaving as designed.

A measurement example, not a resin recipe

Suppose a product's own technical sheet specifies 100 parts A to 90 parts B by weight. For 20 g of A, the arithmetic is 20 × 90 ÷ 100 = 18 g of B, for 38 g total before any permitted additions. This hypothetical ratio must not be used for a product with different instructions, and 20 mL plus 18 mL is not the same measurement method.

Write down the ratio, units and intended batch before opening containers. A product-specific minimum batch size or measuring-equipment requirement still takes priority. The example explains ratio arithmetic only; it does not establish a suitable material, workspace, batch size or processing method.

Weight and volume are not interchangeable

A ratio specified by weight is measured differently from one specified by volume. Components can have different densities, so the same numerical ratio does not automatically work in both systems.

Read the label and technical sheet carefully. If the directions offer both methods, use the stated numbers for your chosen method. Do not convert them by intuition or use another brand's instructions.

Measure with the right equipment

The equipment needs to suit the quantity and measurement method. A scale that is too coarse for a tiny batch can hide a meaningful error. A marked cup is not automatically a precise substitute for a weight-based instruction.

Before starting, check that you understand the manufacturer's permitted batch size and measuring method. This article is an explanation of measurement, not a recommendation to mix a particular resin in an unsuitable workspace.

Keep additives in the calculation

Pigments, fillers and other additions can affect processing. Use only compatible additions within the material supplier's stated limits. “A few drops” from an unrelated tutorial is not a product-specific instruction.

Write a batch record with material names, measured quantities, conditions and observations. Without it, troubleshooting a tacky or distorted result becomes guesswork.

Respond to a mistake before improvising

If you discover an incorrect ratio, do not simply pour in an estimated extra amount after the material has started reacting. Consult the manufacturer about handling the batch and follow applicable disposal guidance.

The same discipline applies when a surface stays sticky: identify the material and process first. Our tacky casting guide lists useful observations to collect without treating one symptom as a universal diagnosis.