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If you’re working with epoxy or impregnating resins, you might be tempted to add a little extra hardener, hoping it’ll speed up the cure. In reality, careful dosing is essential to achieve the results you want.
Why Adding More Hardener is Problematic
It may seem logical that extra hardener would help resin set faster, but this is not the case. Each resin system is carefully formulated with a recommended ratio of resin and hardener—straying from this can cause the mixture to stay tacky or fail to set at all. Rather than accelerating cure times, too much hardener has the opposite effect and can compromise the final result.
Getting the Mix Right: Accuracy is Key
For resin projects, especially those involving structural impregnation, always follow the manufacturer’s ratio—often given by weight (such as 100:55 for Carbon Resin) or by volume, depending on the product. Investing in measuring tools like the 2L Graduated Measuring Cup can help you maintain accuracy, reducing the risk of sticky surprises or wasted material. Remember to mix thoroughly for even curing.
When This Matters Most
Precision really counts in projects that need strength or a flawless finish—such as carbon fibre composites, jewellery making, or clear casting. Incorrect ratios not only affect curing, but can limit impact resistance and long-term durability. Always check the datasheet for specific guidance.
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Mixing resins isn’t guesswork: stick to recommended ratios for a durable, professional finish. For a deeper understanding of dosing the hardener, see our main guide on correct hardener dosing in impregnating resin.