..Now winter has probably found its way into almost everyone in Europe. But is the resin crystallization just a phenomenon that occurs in winter? No, not inevitably, but due to the low temperatures, incorrect storage (including intermediate storage) and especially during transport can lead to crystallization in winter. Crystallization can occur at temperatures as low as 15ºC, but it is more likely when temperatures approach freezing.
How do I know if my epoxy resin has crystallized? You can tell by different factors. It may be that the resin is only slightly cloudy, but it is also possible that you can see a white gritty substance as soon as you open the container, right up to the completely hard epoxy resin component.
What can I do to restore the epoxy resin to its original state? The best way to do this is in a warm water bath at at least 45ºC, but better between 50 and 60ºC for about half an hour. The temperature of the water bath should not exceed 60ºC. It is important to note that the container is opened so that pressure equalization can take place. After warming up, close the container tightly and shake vigorously. The epoxy resin must now cool down to the desired processing temperature (corresponds to the ambient temperature) before it is used. If you ignore this, the resin will react more strongly, which will lead to premature curing and possible stress cracks.
What is best for bringing the water bath to a constant temperature? There are certainly many different and also differently complex and costly methods. For us, however, a sous vide stick has proven to be the non-plus-ultra. They are available from a relatively cheap 50 euros. You simply hang the sous vide stick in the bucket in which you want to take the water bath, set it to the desired temperature and after a few minutes you have your perfect water bath. The temperature remains constant in the range to which the stick has been set, which is really practical.
PLEASE BE SURE TO WEAR PERSONAL PROTECTIVE EQUIPMENT (GOGGLES, PROTECTIVE GLOVES AND BREATHING MASK)!
Is it a sign of poor quality if the epoxy crystallizes? No, it is not, if incorrectly stored or incorrectly transported, this can really happen with every resin. That is why we recommend using container sizes in winter that can still be heated in a water bath without any problems. At least for home use. In the construction sector or in industry there are of course completely different possibilities with which 200L steel drums or even 1000L IBC containers can be heated without any problems.
Does this damage the epoxy resin, or is there a loss of quality afterwards? No, if the epoxy resin has completely decrystallized, it can be used again without problems or impairments.
Good luck and a relaxed winter!