MD Ramsey Wrote:
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> I can't find a good photo of a "burned" or
> "scorched" crown sheet, but am sure others on this
> forum do. Kelly and others will be able to provide
> a more technical explanation.
>
> Basically, when no water is covering the waterside
> of the crown sheet, the sheet itself overheats and
> will start to pull away from the staybolts. If
> discovered before complete failure, looking at the
> sheet from inside the firebox, it looks similar to
> corrugated metal, with a definite change in
> color.

The late Dan Ranger used the term "bagged" to describe this condition.
Thanks for the photo.
>
> Here is a different example where the sheet
> completely failed. You can see a hint of that
> corrugation between the stays.
>
> [attachment 66920 CrownSheetFailure2.jpg]