Step 1: Initial Case Interior
Step 2: Remove Interior
The only special note is to ensure you get almost all the hot melt glue out. It is an absolute bear to pull out in some places, but it all has to come out. I left a small bit in my first case and it came back to haunt me when I went to install the retention straps and the final lining.
Step 3: Prep for New Base
The tape will prevent any of the expanding foam from sticking to the aluminum. If it does get on the aluminum it has to be scratched off, marring the finish.
The blue tape will also give a guide as to where to fill the case with expanding foam.