I don't get it !!?!?? Fender 9050ML's are corroded..

[SharpCat]

Why does stainless steel rust?

 

[OneNut]

So the acid test seems to show
Core - carbon
Wrap 1 - carbon
Wrap 2 - carbon
Flat outer wrap - stainless.

Based on the crud coming off each layer

 

[Deleted member 271037]

So the acid test seems to show
Core - carbon
Wrap 1 - carbon
Wrap 2 - carbon
Flat outer wrap - stainless.

Based on the crud coming off each layer
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Very interesting. I've always believed that Roto steels = carbon and all other manufacturer's steels = stainless. But apparently that's just a myth. At least when it comes to ALL parts of the string. But I'm no expert on metallurgy.

I guess it doesn't really matter as long as the strings sound great and are stored in reasonably normal conditions. I've NEVER experienced anything like the OP. Not even back when I kept some of my basses (out of their cases) at a rehearsal space in a damp, old wooden boathouse with salty seawater right outside the door! The only problem I had was that my basses stank of fish and tar. Especially when they were exposed to the heat of stage lighting... The audience at the front row probably thought the entire band had a serious hygiene problem!

 

[2saddleslab]

Fender may advertise their flats as stainless, but having played them since the change, I can tell you they are not. Stainless is exactly that: it does not rust. These strings rust if not careful.

Oh it certainly can rust, depending on the alloys used to create it. My dad worked his entire career in metals. He often made custom stainless steel projects for me [chopper forks for my Stingray, go-kart, etc.] and I was surprised how many of those would rust if not handled properly.

 

[OneNut]

For those that think stainless cannot rust, here is a really nerdy paper from my other hobby of kitchen knives.

Corrosion Resistance Testing of Stainless Knife Steels - Knife Steel Nerds

Skip down to the section called "Salt Spray Testing". Basically shows that pretty much every stainless will corrode under salt water. Which is pretty much what sweat is.

 

[Yahboy]

OK, I just bought a Squier P Bass that is in very nice condition; very clean and looked to have been well taken care of. It has this set of Fender 9050ML stainless steel flat wounds on it. Sounded great and that's coming from a guy that has never really gotten too much into flats. Welp, I decided to sell the strings and took a few pics of them...... then I really could see how corroded they were. I decided not to sell these and risk the embarrassment of them possibly breaking or not performing correctly.
Anyhoo, I just wanted to show the pics. Aren't Stainless Flats not subject to corrosion? Is the core non-stainless? Back to my title: I don't get it. Any thoughts?
Thanks.
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Try soak with ethanol , leave it couple day and see what will happen.....