Curing two part epoxy consistently is dependent on the product, proper mixing, time, and temperature. Two part epoxy adhesives (also called two component epoxy, 2K or 2-Cor bi pack epoxy) have a longer shelf life and less stringent storage temperatures than single component epoxies. The mix ratio may be by weight or volume. For example, 1:1 by volume or 10:1 by weight.
Two part epoxy products come in a variety of packaging sizes. You can put large bulk packages of parts A and B into automatic dispensing systems that dispense the mixed product onto the part through a static mix nozzle. For those requiring smaller amounts, consider a side by side bi-pack cartridge to dispense through a static mix nozzle.
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 generally mean the time it takes for the product to double in viscosity. That said, if the application is highly dependent on a controlled viscosity, your usable life will be shorter.
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. The 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 (depending on the product.) You can increase cure speed with heat. The general rule of thumb is for every 10°C 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. Heat Resistant & Two-Part Epoxy
