What is the proper procedure for attaching thermocouples to the workpiece?

Thermocouples must be attached using a portable Thermocouple Attachment Unit (TAU) that spot welds the thermocouple wire directly to the workpiece. Clean the attachment locations to remove scale and rust, strip 1/4 inch of insulation from the wires, set the TAU to 80% output, and press the wires to the workpiece at 90 degrees while maintaining firm pressure. The control thermocouple should be placed in the plane of the weld at the center of the heat zone. (Pages 23-24)