This standard specifies a method for indicating the gel time by the hindered movement of a standard plunger reciprocating in an epoxy resin curing system. This method is applicable to epoxy resin curing systems with a gel time of not less than 5 minutes at the test temperature, but is not suitable for high-viscosity resins or systems containing fillers. When testing according to this standard, the relevant instrument is primarily an automatic gel time tester. Such instruments are typically equipped with a heating bath capable of precise temperature control (with an accuracy of ±0.5°C). Their working principle involves detecting changes in the rotational resistance of a stirrer (or plunger) in the adhesive to determine the gel point. The testing process is automated and automatically stops timing at the gel point to reduce human error. This method provides an important testing basis for evaluating the processing performance of epoxy resins.