31/10/2026
Rust inside firebox - normal or excessive?
Just had my insert (Osburn 2000i) swept in preparation for season 2; put half a cord through it during its first year. No creosote at all, which was good, and I think they did a good job with the sweep and inspection. However during inspection the sweeps flagged what they deemed concerning amounts of rust in the firebox. I don't have a ton of experience with wood stoves, so I'm wondering what you all think. Worse than normal? The sweep flagged several hairline cracked bricks on my chimney as a path that might allow water v***r (his words) in to cause the rusting, but a) I'm not sure I understand how that would translate to rusting *inside* my stove if it's brick on the chimney, and b) I have the entire chimney pretty substantially siloxaned and water beads up on the entire chimney very well. No evidence of water pe*******on in the attic on the CMU (it turns from brick to CMU below the roof line) or anywhere else.
Also, I live in a part of the country that's really humid from April to October, so does excess humidity cause this as well as the humid air sinks down into the firebox? If so, how do I prevent this from occurring moving forward? And do I need to do anything about this current rust now, or let it burn off this winter?