hot water tube (water pump to heater) SS/copper?

Unknown

I've noticed the hot water tubes in various states of disrepair. Mine is deeply pitted and rusty on the external surface. However, when I removed the hose and clamp the surface was accidentally scratched and underneath it appears to be copper. When I move the threaded male fitting back away from the flare the tube surface appears to be a SS or possibly nickle plating. Does anyone know just exactly how they were made, metalurgically-speaking? Also, originally, I believe they were painted the same color as the engine paint, correct? I am planning to fabricate one utilizing 5/8" copper tubing, and possibly have it plated too (any suggestions other than nickle + chrome with no buffing; then paint) in order to strengthen it's rigidity; but, would it need to be plated only on the outside (the plating shop foreman told me he can plate it both internally and externally) ? All ideas welcomed! THANKS!

John

Unknown

I don't know what OEM material would be but you might try a hydraulics/hose shop and have them make you a steel line. Most shops can make them,they are similar to large brake lines and are much more durable than copper and will probably look more original.