Thank you for the ideas, I will keep these in mind. The tape I was thinking of using would wrap around the square side of the adapter to make sure it naturally gets a positive seal onto the roaster ‘pipe’. The same method would be used to provide a tight fit into the exhaust tubing that vents outside. Want to use rigid pipe versus flex tubing for future venting/ filtering idea.
Anyway, the tape is very thin and stable to 400 C. I have a bunch left over from a project I was working on. It’s pricy stuff…not sure I would use this if it wasn’t laying around. It’s called Kapton. Here is a Wiki all about it https://en.wikipedia.org/wiki/Kapton