Charlotte 's Fusible Web - Appliqué thread for bobbins Is it thread or is it glue? Fusible thread. 115 yds. 100% Nylon. Fuses without the stiffness of adhesive web. Great alternative for fusible appliqué, especially when multiple layers are involved. For use in bobbin.  Change the way you think about gluing your appliqué shapes. *If used as a top thread, it will melt to your iron when pressed.