A glue pen including a housing, a heater element, and a feed mechanism. The housing is configured to support a meltable adhesive substance. The heater element is disposed in the housing. The feed mechanism is coupled to the housing. The feed mechanism includes a first actuator and a second actuator. Each of the first actuator and the second actuator is selectively movable relative to the other actuator to move the meltable adhesive substance toward the heater element.