My workroom client Kim loves silk dupioni, and she seems to want some of it in every room of her house. Her latest addition is three large, bright dupioni pillows with a small, 3/4" flange. My pictures (taken in overly bright sun, as the pillows were headed from my home studio to her home) don't do the silk justice, but I know you know how appealing these silks are. One of Kim's pillows is pink, one is glowing orange and the third is reversible from pink to orange. She brought me some excellent quality down-and-feather forms that really fill out the pillow covers beautifully.
Though the tensile strength of each individual silk fiber is enormous, dupioni, with its slubs and variations, is anything but rugged. Recently, as I browsed in Waechter's Silk Shop, another customer showed a staff person in the store a dupioni duvet cover that had shredded along its entire width. The fabricator of this cover had used velcro as a closure without stabilizing the silk at all. After a few uses, the silk fibers pulled apart and the cover was in a sad state.
So dupioni requires stabilization. Yet fusible interfacing changes the character and texture of this cloth, and not in a good way. I like to use an interlining of firmly-woven cotton, such as drapery lining (though it could really be anything that is stable and does not show through to the face of the fabric).
Basting interlining to your face fabric is simple, but it can so easily go awry! Pinning both at the edges and at the center and center area is always necessary for good results, in my experience.
Once things are well-pinned, I use the serger to baste the two layers together. A three-thread stitch works fine, since this seam will eventually be totally enclosed by the flange. Actually, even if it were not enclosed, a three-thread finish would still be just as good as four. I leave the center area pins in place until the pillow is complete, to be completely sure that the layers remain flat and behave as one piece of cloth. Sometimes I have used a temporary quilt basting spray (like 505), but mostly I tend to think that pins are just as easy and certainly less toxic.
Interlined sections, right sides together, with zipper inserted, and ready to be joined.
After pressing the seams open and turning the cover right side out, the flange is sewn. Without a walking foot things could shift around. If I didn't have one, I would pin the layers together (can you believe the overkill?) even though the first seam has already been sewn.
Lapped zipper at the bottom edge of the pillow.
Luckily my client does not have rowdy kids, and her dogs are well-behaved. These pillows should give good service in her peaceful home, but they will still be vulnerable to fading from strong sun and also to surface wear as time goes on. I'm glad to know the silk is well-supported and that the seams will not give way under the minor stresses of opening and closing the zipper and folks leaning against them on the furniture.