One of my frustrations with this forum is that my reply and any other relevant postings on this tangent will still be under "My apprenticeship", rather than being part of a new thread called "Annealing". At least, that's the way it seems to work. Does it have to?
Absolutely not. Every e-mail client I have used gives the option of
modifying the subject line when drafting a reply. When the dialog
goes off on a tangent, such as from apprenticeship experiences to
technical aspects of annealing, it is not only possible but also good
practice to change the subject line to indicate the change, so it
might look like "Annealing [was “my Apprenticeship]”