I made one using muslin as the foundation. It wasn't bulky or stiff. Some use pages from a big phone book and remove the paper. For a light summer quilt I have sewn stings to two layers of muslin and then sewn the blocks together quilt as you go method. If you can find it, Anita Murphy has the best string piecing book I've ever used. Called Reversible Quilts. I have used her method on many of my regular block quilts too.