Crystallisation of Epoxy Resin – Causes and Typical Signs

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First, the good news: the crystallisation of epoxy resin is completely reversible and leaves no residue behind. Similar to water freezing and thawing again, epoxy resin simply changes its behaviour when exposed to cold temperatures or significant temperature fluctuations – the quality remains unaffected.

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How can you recognise crystallised epoxy resin?

Typical signs of the beginning of crystallisation include:

• slight cloudiness of the resin

• suspended particles in the container

• crystal deposits on the bottom or sides of the container

• in advanced stages: complete solidification

Because the crystals that form have a higher density, they sink to the bottom and form milky-white deposits that can gradually spread throughout the entire container.

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Does crystallisation occur with every epoxy resin?

The answer is: partly yes, partly no.

Resins with a high degree of purity and low viscosity are particularly susceptible to crystallisation – especially at low temperatures or during sudden temperature fluctuations.

In other cases, only slight cloudiness may occur without the entire resin actually crystallising.

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What Should You Do if Epoxy Resin Crystallises?

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After opening Component A (resin), its condition should always be checked. Especially during the autumn and winter months, epoxy resin may crystallise as a result of low temperatures during transport.

Instructions: How to Heat the Resin Correctly

If crystallisation is detected, we recommend placing the closed container of Component A in a water bath:

• Start with a water temperature of max. 60 °C.

• If the crystallisation has not dissolved after approximately 1 hour, the temperature can be increased gradually – up to a maximum of 100 °C.

• To speed up the process, regularly turn the resin container and stir the resin thoroughly.

• Depending on the quantity of epoxy resin, this process may take some time.

Important Note

Once all crystals have disappeared, allow the epoxy resin to cool back down to room temperature before using it as usual.

Pro Tip for Resin Processing

For accurate temperature measurement, we recommend using an infrared thermometer.

This allows you to keep a close eye on the temperature at all times and helps prevent processing errors.

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How Can Crystallisation of Epoxy Resin Be Prevented?

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To prevent your epoxy resin from crystallising, it should ideally always be stored at an optimal room temperature of 15 °C – 20 °C. This keeps Component A (resin) permanently liquid and ready for immediate use.

If storage within this temperature range is not possible, we recommend placing the resin in a water bath before use as a preventive measure – as described above. This helps prevent unexpected issues during processing.

Good to Know

High temperatures do not have a negative effect on the resin component.

There is no loss of quality and no curing takes place, as the reaction only begins when Component A is combined with Component B (hardener).

Service Note

If you experience any problems during processing, please contact us before use. Our support team will be happy to assist you.