I haven't seen this addressed but figured I'd provide some info.
We all hate rust and go to great lengths to avoid it.
But most people don't realise they create the issue by introducing items that cause rust.
The most common cause that we create is using dissimilar metals. These two different metals cause, Galvanic corrosion.
Here is a great article and may be of use to some:
http://trailer-bodybuilders.com/mag/tru ... ar_metals/
Since most of us use wood in trailer builds here's an article that addresses the rust caused by metal and wood (or by whats in the wood).
http://www.fpl.fs.fed.us/documnts/pdf1987/baker87a.pdf