Step 1: Old blow molded case I had sitting around.
Step 2: The insides... not very camera friendly yet
Step 3: Empty shell
Oh yeah, safety glasses (or a complete face shield in my case) since tiny bits of plastic go flying everywhere when you least expect it.
Step 4: The protection...
I got 2 squares of the stuff that were a bit larger than the case. With a sharpie marker I outlined the case onto the foam and cut with a bread knife, results shown.