Wet the chamber walls with water before you smoke it, and smoke it super slow. Don't even try to keep it going. Once you have a protective carbon insulation you can smoke it in a more normal manner. But go too fast and hot and it may crack.
Jesse,
Thanks for the reminder. I will be very careful.
I'm still traumatised by the 1921 Loewe bent billiard that cracked all along the shank when I fired it up the first time. Luckily it is an army/military mount with a silver ferrule. I have smoked it since, with no issues.
I suspect I did not allow the shank sufficient time to dry out properly after cleaning it. The shank and mortise was so heavily tarred up that I left alcohol-soaked cleaners in for over 48 hours. These days I allow at least 2 weeks for shanks to dry after an alcohol treatment.