More expensive lampshades are often lined with a liner fabric that is different from the exterior finish of the lampshade. Because the liner is closer to the light bulbs, it receives more light and heat than the outer shade, and this can cause the liner to fail before the lampshade. Repairing the liner is tricky, but if you can sew and use a glue gun, then you can usually make the lampshade look good as new.
Insert the seam ripper into the seam that attaches the liner to the frame. Cut the seam threads and pull gently on the liner to remove it. Sometimes adhesives are also used, so you need to separate the liner from the frame and the main lampshade covering.
Place the liner on the work table. Rip open any additional seams to create individual pattern pieces. Place the fabric pieces over kraft paper and trace out a new pattern. You may have a single curving pattern or several identical panels. Make sure your pattern has a 1/4-inch seam allowance.
Check to see if the frame of the lampshade is covered in seam tape. If the tape is damaged or missing, wrap the bare frame in matching colour seam tape. Apply hot glue to the frame and wrap the tape through the glue, overlapping the tape so that all the wire is covered.
Pin your paper pattern to your new lining fabric and cut your fabric. Machine sew your side seams together and tuck the fabric lining up inside the lampshade to see how it fits. The lining should be just small enough to barely touch the seam tape over the ribs.
Fold the top hem under so that the raw edge of the hem is against the wrapped frame. Clamp the liner to the top frame with bull clamps to hold it in position. Fold the bottom hem under so that its raw edge is against the bottom wrapped frame. Clamp it. This is your final check for the fit of the liner.
Sew the liner by hand to the seam tape starting at a liner seam. Liner seams will line up with the vertical ribs of the lampshade frame. Use a small whip stitch and sew the top and bottom of the liner securely to the lampshade.
Add new trim over the top and bottom edges of the lampshade to hide your hand stitching. A white rayon/acetate fabric is most commonly used to line lampshades, as it holds up well to the intense light and heat. Most rayon blend fabrics will work fine. Simply keep the bulb at least 1 inch from the lining.