SPC always lists this on smoked Estates, and I’ve always assumed, it’s simply describing the amount of carbon/cake inside the chamber, not referring to damage.
Here’s an Eltang listed as ‘Mild Chamber Carbonizing’. I assumed that meant the chamber has a mild buildup of carbon, otherwise the listing would mention damage.
Danish Estate Tom Eltang
I’m not sure what your title means, because cake is the formation of carbon.
When you mentioned worn down pipes, it helps to be more specific as to where this wear is you’ve noticed.
Briar is pretty much impervious to fire, when it’s been properly processed/cured. So if it’s a good grade of wood, good dimensions, meaning not overly thin walled, it shouldn’t be wearing down.
A 1mm carbon layer is all that’s needed inside the chamber. Before the carbon layer is formed on a new uncoated pipe, if smoked to hot, could form small hair line cracks. A thin carbon layer helps protect against cracks and possible burn outs, if smoked to hot.
The carbon layer also create insulation for a cooler smoke.
With a nice, evenly formed 1mm layer throughout the chamber, the briar should not be getting worn out, using good briar and craftsmanship.
As mentioned before, if this is up around the rim, if the briar was thin in this area to begin with, the most likely culprit is bad reaming.
And, you don’t need a reamer, if you always wipe the chamber out, with like a paper towel, when starting out with a new pipe, and maintaining it this way, throughout the life.