error1 posted:

Cinder blocks would probably weigh less, due to how CRT screens work. There has to be a vacuum inside the glass tube and the larger it is the thicker glass they have to use to avoid it imploding from atmospheric pressure. Especially when designing it to have a flat front like the later CRT models had, they wound up using super thick glass. Older curved displays distribute the load better, like a curved stone bridge vs a flat bridge.