Resin left sticky, soft or liquid? Find out how to save it

When working with epoxy resin, it can happen that even after the expected curing time, the resin remains sticky, soft, or even liquid. Often we don't even realize we made a mistake during the process – and we’re left standing over the mold wondering what to do. Mistakes happen, and luckily they’re often fixable if you know the causes and how to proceed.

💡 Why epoxy resin didn’t cure: Top 5 most common mistakes

There are several common reasons why resin may not cure properly:

• Incorrect mixing ratio – The exact ratio of resin and hardener is crucial and must be weighed precisely to the gram. If the ratio is off, the resin may not cure at all or only partially. Also, stick to the minimum recommended mixing amount (usually 50 grams), so the curing reaction can begin properly.
• Insufficient or improper mixing – Resin and hardener must be thoroughly but slowly mixed (3–4 minutes in one cup, then pour into a second and mix again). Poor mixing can leave uncured areas that remain soft.
• Too much color or using the wrong type – Only use colorants made for epoxy resin. A good supplier will also tell you the maximum amount of color you can add without affecting curing.
• Inserting an object with moisture or grease – Water, oils, or other substances released into the resin can interfere with curing and leave a sticky or soft surface.
• Incorrect temperature during curing – Keep the temperature stable and within the recommended range during both processing and curing. Low temperatures slow or stop the curing process, and high temperatures can cause undesired reactions. Fluctuations can prevent curing entirely.

💡 How to fix uncured resin: Solutions based on the problem

If your resin is still soft, sticky, or liquid after the recommended time (check your specific resin), try the following:

👉 What to do if the resin is very thick but still soft

• Place the mold with resin in a sealable plastic bag and freeze it for several hours or overnight.
• Take it out and immediately peel out as much as you can. Be careful: the resin will thaw quickly, and you may need to repeat this process.
• Use wet wipes (baby or cleaning wipes) to clean off any residue.

This trick makes it easier to remove soft, uncured resin without damaging the mold. The piece itself may not be salvageable, but you’ll be able to reuse the mold.

👉 What to do if the resin remains liquid

• Carefully pour out as much liquid resin as possible from the mold.
• Clean the mold and residue with wet wipes.

Do not try to add more hardener or resin to the uncured mix. As mentioned, epoxy resin is sensitive to exact measurements, and it’s nearly impossible to guess the correct amount. You’d likely waste more material instead of fixing the issue. The upside: you’ll save the mold.

👉 Resin is sticky on the surface? Try tempering or a new layer

• Try tempering: put the object in an oven preheated to 50 °C (122 °F) for about 30 minutes.
• Let it cool down slowly at room temperature.
• Tempering can sometimes help finish the curing process.

💡 If only the top surface is sticky, you can coat it with a thin new layer of resin and let it cure again.