Quilting Grandma
The best and esiest thing I have found to use for foundation piecing (paper piecing) is light weight pellon. Get the most sheer one you can find, cut square the size desired and sew on the strips of fabric. Turn the block and square up. This works for me so much better than using fabric for the base and it is less bulky. Don't worry if the pellon does not come to edge of fabric in some spots along edges of block. Sometimes sewing will shrink the pellon a little depending the kind of fabric used