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Why does my epoxy have crystals in it?



Crystallization of liquid epoxy is a known phenomenon that frequently surprises users who are not very familiar with epoxies.  Crystallization may look like crystals, snowflakes, cloudiness, fog, turbidity, and even a solid, or a solid sediment, in the epoxy resin.  The reason some epoxy resins crystallize has to do with their ‘super-cooled’ nature – they are supposed to be solids at room temperature, but have remained liquid below their solidification (freezing) point.  Therefor super-cooled liquids have a natural tendency to crystallize.  The timing of crystallization is highly variable and unpredictable.  Factors effecting crystallization include resin purity, viscosity, additives, moisture content, the presence of ‘seed’ crystals, and environmental variables such as storage temperature and even a sudden cold shock.    Crystals can be easily eliminated by increasing the temperature of the liquid resin to about 50°C (about 122°F) for a period of hours or until all signs of the crystals are gone.  Allow the resin to cool back to room temperature, and proceed to use normally.  There is nothing about crystallization that is damaging to the epoxy.  It is the same as water freezing, and melting ice: the water is exactly the same before and after crystallization.

SM6AskFOCIconAnswered by AskFOC Technical Team June 21, 2015



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Kathleen Skelton

About Kathleen Skelton

Kathleen Skelton, Director of Strategic Marketing's experience includes management positions at Lightwave, KMI Research, PennWell Publishing, Beacon Communications, and Security Innovations, Inc. As a strategic marketing director, she utilizes her expertise in business development, online strategy, marketing planning, digital best practices, standard operating procedures development, and database design, management and training. Kathleen has global business and marketing experience. Outside of FOC, Kathleen is passionate about her volunteer work for several organizations and works with youth groups teaching business strategy for various community projects. In her volunteer work, Kathleen is committed to developing tomorrow's leaders through exciting, strategy-focused business education. This mission guides all of her work outside of the corporate office. Kathleen graduated from Curry College with a BA in Communications and Education and minors in English and Psychology. Kathleen resides outside of Boston, MA with her husband and four children. Follow @KATHLEENSKELTON