Magna-Tac E645 is a thermosetting adhesive that requires heat to fully cure. If the epoxy is not fully dried before heating, the epoxy will not cure. Similarly if the epoxy is not heated at the right temperature the epoxy will not fully cure. Without a full cure, the epoxy will fail in applications. To ensure the bond is optimal, follow the dry time and cure time tips below.
Drying E645
Once the adhesive is applied to the parts/pieces for bonding, it must be thoroughly dried before curing. Drying may be accomplished at room temperature or by forced drying in circulating air ovens. If all of the solvent is not removed before curing, blisters or weakening of the adhesive film will result. Thicker or more highly diluted films will take longer to dry.
At normal room temperatures, air drying may take 4-8 hours. For best results, force dry at 125F for 60 mins or at 200F for 10 minutes. Do not dry at temperatures above 250F (adhesive may start to cure at that temp).
The adhesive dries to a tack free surface at room temperature. Coated parts may be stored before curing for periods of up to 6 months at room temperature. However, the adhesive film must be clean and dry.
Heat Curing
MagnaTac E645 will begin to cure at temperatures above 250F. Normal cure temperatures at the glue line range from 265F-400F. Curing temperatures below 375F are recommended to avoid degradation of the adhesive
Magna-Tac E645 is thermoplastic, when exposed to the right heat temperatures the epoxy will begin to flow and wet out on the surface of materials being bonded.. As the temperature is raised, the cure will complete and the bond will be ideal for end use.
Gelling
For certain specialized applications, some users prefer to retard the normal flow out. This can be done by partially curing the adhesive at contact pressure only for about 1/4 to 1/2 the “minimum gel time” shown in figure 1. Any of the normal time and temperature cycles listed may then be used for subsequent curing
The figures refer to the temperature of the adhesive film. Allow sufficient time for the stack to attain the correct temperature. The time required for cure depends on the temperature selected, on the mass of metal and on the heat capacity of the metal in the laminate. The temperature chosen depends on the heat sensitivity of the materials being bonded and time limitations in production scheduling. If the maximum cure time is exceeded, over-curing which may cause failures – can result.
Curing Pressure
Pressure is not needed to affect the bond but is essential that the coated surfaces be in complete and intimate contact over the entire area of the materials being bonded. Accordingly, sufficient pressure must be applied to assure such contact. The specific amount of pressure needed will vary, depending upon the flatness of the components, porosity, resiliency, etc.
