Epoxy crystallization can occur in foods, minerals, and epoxy resins or curing agents. Recognizing the phenomenon can help you ensure your material is properly prepared before attempting a cure.
What is epoxy crystallization?
● Crystallization is the natural solid state of a product
● Epoxy resins and hardeners can all experience crystallization
● It primarily occurs with two component epoxy systems, but can also occur in one component heat cure epoxies
● Crystallization does not mean defective material
How to recognize epoxy crystallization?
● Cloudiness, free floating crystals, crystal masses, or completely solidified material
What causes epoxy crystallization?
● High purity of material
● Low viscosity of material
● Extreme cold temperatures (-40 °C)
● Temperature fluctuations
How can you reverse resin crystallization?
● Heat crystallized material between 50 to 60 °C for 1 to 2 hours. Container size will affect the length of time needed for decrystallization.
● Stir material including container sides and bottom to ensure all crystals have been melted and that heat has been evenly distributed.
● If crystals are still present, continue heating and repeat stir process until there is no evidence of crystals.
While reversing crystallization can be effective for some resins, avoid this method with one component heat cure resins, which cannot be heated to reverse crystallization as product damage may occur.