Down coats are great because they're super warm, but they are also usually a little more expensive than coats with synthetic lining. The extra cost makes it worth mending things like a damaged lining, if possible, before all the down falls out. Don't worry if the down is already gone, though, you can buy new down to sew into your coat, or even snag a few down feathers out of an over-stuffed down pillow.
Tips Before You Start a Down Coat Lining Repair
You will need a heavy duty or industrial sewing machine with a sharp needle installed to avoid making big holes in the coat's shell if you have to repair the quilting.
Repairing a Weak Seam
If the problem is just a seam that has let go, you have the option of hand sewing the gap shut with coarse thread and a hidden or back-stitch.
Patching a Hole in a Down Jacket Lining
Step 1 - If the lining has a hole, cut a patch of fabric larger than the hole by at least 2 inches all
the way around, using the closest fabric match you can get to the original lining.
Step 2 - Fold the patch's raw edges under 1/2-inch, then center and pin the patch over the hole.
Step 3 - Hand sew all the way around the patch using the whipstitch or a hemming stitch, and remove the pins as you go.
Step 4 - Now flip the coat over so you can see the outer shell. If the quilting looks like one big blob with the stitches gone, use the sewing machine to sew over the original stitching lines, replacing the quilting stitches.
Now all that's left to do... trim off any stray threads you see and go enjoy your down coat for another season.