Start with copper samples, and produce some practice beads to get a feel for the thickness of the material and for the arc size needed to melt the copper. Mount the copper samples on the work bench. Adjust the tungsten electrode to protrude about 1/8 to 3/16 inches in front of the ceramic nozzle. Make sure the electrode is sharpened to a point, and that it is smooth to avoid scattering the arc. Set the gas flow to 10 cubic feet per hour. Check to make sure you have filler rods for TIG copper welding, if needed.
Turn on the gas, and hold the tungsten electrode about 1/8 inch from the copper where you want the weld to start. Push down the floor pedal to start the arc. Hold the electrode at right angles to the copper surface, and move it in small circles until you have created a puddle of molten copper. Push down on the floor pedal to increase the current and the size of the arc, if necessary. Don't let the tungsten electrode touch the copper. Tilt the tungsten electrode back at 75 degrees and run a few practice beads. Let the material cool and examine the beads for penetration into the material, continuity and strength.
Mount the copper pieces to be welded on the work bench. Repeat the above procedure, compensating for any problems you found on the practice beads. If the beads were too high, go more slowly and use a bigger arc by pressing the floor pedal for more current. If the beads penetrated the copper too much, go faster with a smaller arc. Add filler rod for filling gaps in thick material. Hold the filler rod above the molten copper at a small angle to the direction of the bead. Periodically back off the arc from the front of the puddle, and dip the rod in to add as much material as is needed. Don't let the filler rod touch the tungsten welding tip. Complete the required beads at a steady speed to give even welds.