So a cob gets warm to hot while smoking and the glue doesn’t loosen but some warm water would somehow harm the glue? I’d like some help understanding that.
It happens around the shank where it connects to the cob. Looks like it may be from the soft wooden shank expanding and contracting. Maybe the glue is too stiff to handle this, it just pulls away.
I know there's water produced from smoking, but it may not penetrate from the inside as much as it does from the outside. The outside of the pipe is dry and ready to soak up any moisture, the inside has a protective layer of carbon.
This is all just speculation, no science involved.
I used to be an advocate for washing cobs, but then I had a few get loosey goosey. I stopped washing them after suspected that the water was causing it.
BUT... Corn cob pipes are disposable items... So if you wash them for a year and it tears 'em up, you aint out much.
If you smoke a cob pipe regularly it's going to fail anyway... These people who claim they last forever don't smoke them often enough to wear 'em out.