Cold

[John Folsom]

I think oldtvman has it right. Moisture is the biggest issue. All the CRTs went through at least 600 degrees F in the oven while they were processed, with a change from ambient to hot and back to ambient in only 3-4 hours. Much more extreme than any temperature delta they will see just sitting exposed to the heat and cold of ordinary weather. The expansion characteristics of the glass to metal joins were carefully engineered to expand and contract at the same rate. Otherwise, no CRT would ever survive being built in the first place.