Originally Posted by
seth10015
I heard back from Co-Motion today & I believe they are in Hueyhoolihas's camp. They state: "The rust inside is superficial and actually adds a protective layer, despite that sounding counterintuitive." I don't know enough about metals to have a valid opinion, but it seems to me $5,000 frames should be protected against the possibility of rust in some way. That said, I knew it was not and am sorry I didn't use Frame Saver when new.
Thanks for all the comments.
Steel needs a high chromium content to form a protective layer (chromium III oxide), which is why stainless-steel exists. "superficial" rust will continue the rust cycle, surface rust leads to pitting corrosion. You can stop it with frame-saver or something similar by cutting off oxygen from reaching the metal (whether you remove the rust first or not). If you want to remove the rust, try the classic/vintage forum for threads on the topic. I flushed out a paramount with phosphoric acid with good results. There's a pretty good article on the Sheldon Brown site covering rust removal.