Cob: Masonry heaters

[Banks]

I'd like more info on cob heaters, too, but with metal 'innards' like a
draft-controlled firebox to direct heat to a cooktop & oven.  Could this be
done?   The thermal mass & safety of a cob exterior, combined with the
utility of an old fashioned cookstove.....

I wonder how the cob would hold up.  Would the iron change sizes with
heating/cooling, crumbling the cob.   If anyone's tried this please let me
know.

Joy