I saw a Dresden Plate quilt made from silk ties at a quilt show this weekend and it was stunning. After you've taken the ties apart, set your iron on silk and press them. I've done this an it worked great. I even used steam and set my iron a little hotter than silk it was fine. You will probably have to use a fusible stabilizer on the back of the ties to give them a little body so that they sew easily. If you do, use a light weight or featherweight stabilizer. Some of those silk ties are made of really lightweight silk.