A month ago I learned that because of the hard water here in Austin and also because I have a water treatment system for it, that there are rods in all hot water heaters that are made of magnesium (sometimes Aluminum but Magnesium is supposed to be better). Their role is to direct corrosion to the rods first and if changed periodically they will extend the life of your steel tank. They're called sacrificial anodes because they die so your tank doesn't have to.
...so I started thinking about all the other steel things that rust and could be saved with the same kind of principle. I'm planning on tracking down a piece of magnesium and bolting it to the Northern Tool trailer frame I am building on. If it does nothing, the worst that could happen is I will be out the price of a cheap piece of magnesium.
Anybody else try that? Seems like a good precaution. You just have to make sure there is electrical continuity between the piece of magnesium and the steel part you are trying to protect.
Here's what a 6 year old anode rod from my water heater looks like next to the new replacement...https://www.facebook.com/photo.php?fbid=10213499861154823&set=pcb.10213499884875416&type=3&theater
Just a thought.