An insulated glass secondary edge sealing device that dispenses sealant to insulated glass units including at least two panes of glass separated by a spacer, including a fixed sealant dispensing head, a table that supports the insulated glass units, a fence, a depth sensor, a linear motion encoder, a metering device. The sealant dispensing head has a dispensing nozzle and a corner dam. The dispensing nozzle includes a floating insulated glass unit contact surface and the corner dam is shiftable between a retracted position and an extended position. A control unit receives signals from the depth sensor and the linear motion encoder and controls the metering device to dispense a measured flow of sealant based on the depth of the inset of the spacer and the movement of the insulated glass unit parallel to the fence and relative to the encoder.