Got any *real* auto parts stores in your area? Go there and buy 4' sections of steel brake line, in several sizes. It's galvanized, so no need to paint for corrosion protection. AN3 fits in 1/4" OD perfectly, but I keep several sizes on hand for all kinds of stuff, including bushings. Cut it with a regular tubing cutter for square ends.
Rigid aluminum or even copper or brass should work too for something light, but the brake line is easy for me to get, and virtually no weight penalty for such small segments.