Hopefully when my Starrett straight edge arrives again today from Amazon, this one will not be damaged. If that is the case, I want to keep it that way. I thought I would make a case for it out of two boards, one routed out for the straight edge and the other hinged and latched as a lid.

With regards to corrosion, Is there a would choice that is preferred or that should be avoided? What other steps would help to avoid rust?