Originally Posted by Walking Bear
When I have installed them on a curve, lay out the zipper on the fabric and pin. Then sew it to the fabric on both sides of the zipper. Then cut the fabric on the backside of the zipper. Fold it back and put a second row of stitches.
If you sew the fabric over the zipper when you cut and fold the zipper tape is hidden and the result looks like a professionally installed zipper. It's a bit pickier than sewing the zipper on top but I like the result better.
Make sure the first row of stitches is at the edge of the zipper tape. Otherwise you can have trouble folding the fabric under. It is easiest if you turn everything over and sew the zipper upside down onto the _wrong_ side of the fabric. Turn it all right side up and follow the zipper as you clip down the middle. Keep the zipper closed while you are cutting. Then fold and stitch with the zipper foot.