I recall seeing a thread that addressed this issue and neglected to Favorite it. I have a blank that is full of them. Not exactly bubbles but pock marks in the material. I read the thread and said, So that's what causes it! I had couple of places today that had minor issues and I had enough material to carefully, with light touches, turn them down. Can anyone help here? What am I doing wrong? Not sure what to use for search words. As always, thanks.