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Consistent Two Component Epoxy Curing

Two Part Epoxy Adhesives

Two part epoxy adhesives (also called two component epoxy, 2K or 2-Cor bi pack epoxy)  have longer shelf life and less stringent storage temperatures.  The parts are presented in a ratio for example 1:1 by volume. Or 10:1 by weight.

Two part epoxy products  come in a variety of sizes, large bulk packages of part A and part B can be placed into automated dispensing systems that dispense mixed product onto the part.  For those requiring smaller amounts, products are packaged in a side by side bi-pack that is dispensed through a static mix nozzle.

Mixing and Pot Life of Two Part Epoxy Adhesives

It is possible to weigh or measure the part A and part B and hand mix.  But the ratio must be accurate and the mixing thorough to maintain consistent results.  For industrial use, a controlled process is recommended.  However, should you choose to measure and hand mix, mix only what you will use during the “usable life” or “pot life” or “open time” of the product. These terms are loosely defined as the time it takes for the product to double in viscosity.  That said, if the application is highly dependent on a controlled viscosity, you usable life will be a shorter period of time.

Two Part Epoxy Curing Time

The other value often noted on data sheets is fixture time or handling strength.  These have various definitions but the purpose of the listing is to show when the two part epoxy will set enough to unclamp or move the part.  Full cure of a two part epoxy can be several days.  However adequate strength for further assembly, or packaging can be reached within minutes or hours.  To increase full cure speed, heat can be used.  The general rule of thumb is for every 10C increase in temperature the cure time is cut in half.

Some two part epoxy adhesives require a heat cure to achieve their ultimate temperature resistance. https://www.permabond.com/blog/2014/04/14/high-temperature-resistant-2part-epoxy/