This image is of the tear I created when I was stretching the vinyl down into a depression and compund curve. I over heated and over stretched, maybe used the wrong tool. In any event it ripped.
My take away on all of this is the need to manage the material. When you stretch and/or heat the material that energy has to go somewhere. That energy manifests itself in the form of ripples and ripples can turn into creases. I have some ideas of how to manage this process a little better now that I have tried it. More to come.