Can Rust Form Under the Seasoning?

[LVaughn]

Occasionally I'll pull a pan out of the lye bath to find patches of rust that were not evident before. I have sometimes assumed that my lye was weak and allowed the iron to rust, but tonight I found it on a pan from my freshly renewed lye bath. Can the iron rust under the old seasoning and crud buildup? Or has someone seasoned over the rust?

[Doug D.]

Even a weaker than normal lye solution shouldn't allow rust to form, pH would likely still be too high. I can't see someone purposely seasoning over rust. It might be possible, but unlikely that a crudded-over pan was left submerged in water long enough to do something like you're describing, but I've never seen it.

[Russell S.]

After viewing YouTube, and Facebook Groups on Cast Iron, nothing surprises me anymore. Some folks just remove loose surface rust and season over the rest. I just pulled a #14 unmarked skillet (I’m pretty sure a Wagner) out of my lye bath that had rust and minor pitting under the seasoning. The pan was completely black on the surface and the rust and pitting wasn’t noticeable at all before the lye soak. It’s in the E-tank now.

[LVaughn]

It happens just often enough to make me wonder what the heck is going on. Oh well.