Epoxy Mounting

Yes, with epoxy resins this is very much the case. The larger the amount of resin the higher the temperature can get. When a 40 or 50 mm/1 ½ or 2″ mounting cup is used, and the sample is quite small, cooling of the mount can be necessary to avoid excessive temperatures and high shrinkage.

Epoxy resins cure in a so-called stoichiometric reaction. Here the accurate amount of both components, hardener and resin is critical otherwise a small amount of one or the other compound will remain uncured. This often results in sticky samples. To avoid that, accurate measuring by weight is recommended.

Epoxy resins cure in an exothermic reaction. That means they create heat when curing. In general, the larger the amount of epoxy to be cured, the higher the temperature will get. This can result in excessive shrinkage, melting moulds and ultimately, destroyed samples. However, there are epoxy resins that cannot start this process on their own, they have to be heated to get started. Our Aka-Cure Quick is one of these products. When mixed with the Aka-Resin Liquid Epoxy it must be heated to 80 °C to start the curing process. When left at room temperature, the polymerisation process will start, but only very slowly and without increasing the temperature. After 24 hours the mount is semi-cured but too brittle for preparation. A post cure at 100 °C for about 1 hour will complete the curing process and result in a fully transparent mount without shrinkage.