Measure the stage to determine the size of curtains you need. Measure the total distance from one end of the stage, which is usually hidden by a draping, to the other. Purchase enough drapery fabric to span this distance, plus two feet of additional fabric to serve as hems and slack in the curtains. Measure the height the curtain needs to span, and add eight inches to that measurement when purchasing fabric.
Craft the stage curtains. Make two identical curtains, each using half of the fabric you purchased. Hem the top and bottom edge with 4-inch hems and each side edge with 2-inch hems. Insert curtain pins along the top of the reverse side of each curtain.
Cut heavy-duty curtain track, which you can purchase from a theater supply company or through some hardware stores, the width needed to span the stage. Measure from the floor to the top edge on each side of the stage to ensure the curtain hangs level, and attach the curtain mounts at these points. Using an electric drill and screwdriver and hardware provided with the mounts, affix the curtain track mounts above the stage.
Install a traveling glide – the hook the pulley line attaches to – into the center of the curtain track, and install enough standard glides into the track to support the curtain. Depending upon the weight of the curtain, you may need to use one glide for every four to six inches of curtain. Place caps provided with the curtain track on its ends to lock the glides in the track.
Mount pulleys parallel to the curtain track at each end of the track using the axle and hardware provided with them. Insert pulley line between the pulleys, connecting it to each traveling glide. Start by threading the line on the top edge of one pulley, through the traveling glide on that side of the curtain, and under the bottom edge of the opposite pulley. Continue threading the line so it wraps above the top edge of the second pulley, through the second traveling glide and under the bottom edge of the first pulley. When threaded properly, the line will be in a figure-eight pattern. Cut the line so it fits snugly on the pulley system, and heat-splice its ends together using a lighter.
Mount another pulley directly below one installed in the previous section at waist height to operate the opening and closing mechanism using an electric drill and hardware provided with the pulley. Thread pulley line in a single loop over the top of the upper pulley and around the bottom of the lower pulley. Cut the line so it fits snugly between the two pulleys, and heat splice it together using a lighter.
Test the tension on the pulley lines. If installed correctly, pulling the line will transfer movement to the pulley system above the stage, allowing the curtain to open. If the pulley lines are too loose to force movement, adjust their tension.
Hang the curtains by placing the pins inserted in Step 2 into the glides installed in the curtain track in Step 4.