If your scraps are large enough to butt together, use light weight fusible interfacing rather than stitching. (You will need a steam iron and a pressing cloth.) You can spend a lot of money purchasing a small package of the same thing. But you can also buy it as yardage the cut your own strips. Our LQS sells this interfacing for $1/yard and it is either 60 of 72" wide. Just ask for it.