I've been watching this post and think I'm starting to understand, but still have questions. The rod is to keep the pipe insulation from getting curvy, got it. You are using the slit in the pipe insulation only as a straight line for reference, not putting the layers of the sandwich between the slit edges, got it. I understand the glue basting. What I do not understand is whether or not you end up with all three layers of the sandwich pinned to the insulation at once, or, does each layer get treated separately? I appreciate the time you have devoted to putting this online to help others.