I have had done that, sometime left to long, yup it crack right to the middle. now, I wonder if it's the blowdryer I use, don't get hot enuf to shrink the wrap quick enuf that the longer I use it the more it gets melted on edge. could that be it? would a more efficent heat gun work better, if so, what kind, cause the heat gun I have, is MEGA POWERFUL AND MEGA HOT...it's more industrial kind...lol not sure if that's right for shrink wrapping. any help would be appreciated! Hugs Dani