Therm O Web SpraynBond Fusible Adhesive is a heat activated, permanent spray adhesive. Spray the back of your project and press down on the right side with a hot iron for about 30 45 seconds. Once ironed, the adhered item doesn't need to be sewn, but can be if desired, won't gum up needles. The thicker the application, the stronger the bond. Washable, dry cleanable and colorless. Acid free and odorless. Permanent Hold. 6.5 oz.