On 11/14/22 09:19, Jon Elson via cctalk wrote:
  On 11/14/22 06:25, Shoppa, Tim via cctalk wrote:
  I've been reporting on 9-track tape seal
failures over at
 least the past 2 decades here.
 Very very few of the older (I think of them as IBM or
 70's/80's style) "hard plastic" tape seals failed.
 
 Yup, these seals were under tension.  I think the failure
 mechanism is the square holes in the seal band develop
 cracks at the outer corners, and the tension continues to
 expand the crack.  
The soft seals were Polyethelene, I think, the "hard" seals
for use on drives with auto-loaders were Cyclolac, AKA ABS,
and were not in much tension when closed.
Jon