The Correct Resin-to-Hardener Ratio (and Why It Matters)
Most craft epoxy resins use a 1:1 or 2:1 resin-to-hardener ratio by volume or weight, but the exact number varies by brand — always check your specific product's label or data sheet. Getting this ratio wrong is the single most common reason resin stays sticky or never fully cures.
Based on hands-on resin work by practising Indian artists troubleshooting failed cures across multiple resin brands.
Why the Ratio Is So Precise
Epoxy resin cures through a chemical reaction between the resin and hardener, not by air-drying like paint. Too little hardener leaves unreacted resin that stays soft; too much leaves excess hardener that can cause cloudiness, excess heat, or a rubbery texture. There's no "close enough" — the ratio your manufacturer specifies is the one that actually completes the reaction.
How to Measure Accurately
- Use a digital scale with at least 0.1g precision rather than volume markings on cups.
- Zero the scale between adding resin and adding hardener (tare function).
- Follow your brand's exact ratio — common ones are 1:1, 2:1, and 3:1 by weight or volume, so don't assume based on a different brand you've used before.
- Mix for the full recommended time (usually 3-5 minutes) — under-mixing causes the same soft-cure problem as an incorrect ratio.
Ratio errors are proportionally worse in small batches — a 5g mistake matters far more in a 50g pour than in a 500g one.
Common Ratios by Resin Type
| Resin type | Typical ratio | Measured by |
|---|---|---|
| Standard craft epoxy | 1:1 | Volume or weight |
| Deep-pour / tabletop epoxy | 2:1 | Weight preferred |
| Some fast-cure formulas | 3:1 or 4:1 | Weight (check label) |
Always confirm against your specific brand's data sheet — this table is a general reference, not a substitute for it.
Got bubbles after mixing correctly?
Our bubble-removal guide covers the next step.