Yes. Thicker materials such as denim and canvas will require more time than the standard 25-30 seconds needed for thinner materials such as T-shirt cotton. For best results, increase the dwell time to 40 seconds on the face of the material and 40 seconds on the back when using iron-on transfer sheets such as glitter, hologram, flock, and film on thicker materials. Wait until the material is completely cool before peeling it off the carrier.