Re: [ARSCLIST] CD longevity (was Re: [ARSCLIST] Reel-to-reel tapes: storage conditions and potential content retrieval)

[Jerry Hartke <jhartke@xxxxxxxxxxxx>]

Properly manufactured, high quality CD discs can be bent 180 degrees without
cracking, while poor quality discs having lots of internal stress and high
birefringence will easily crack and even shatter. If you try this, wear
protective gear, especially for your eyes.

Good quality CD protective coatings, perhaps Roger's "laminations", are
quite permanent, while poor quality discs may have pinholes in the coatings
or metallization. The issue is variable manufacturing quality, not generic,
just as with most of the products that we buy.

Jerry
Media Sciences, Inc.
 
> They crack almost as easily as 78s do,and unlike 78s,the lamination on the
> surface is not permanent.If not handled properly it peels.leaving you with
> a clear plastic disc.This has been discussed here,and elsewhere ad
> nauseum,and I,for one,find the topic boring,and redundant.
>                                          Roger
> 
> Mike Richter <mrichter@xxxxxxx> wrote: Don Cox wrote:
> 
> > Manufactured CDs (with physical pits) should last as long as 78s.
> 
> That is far from clear. The pits and lands themselves may survive, but
> they are read by reflection from the vulnerable metallized layer.
> 
> Mike
> --
> mrichter@xxxxxxx
> http://www.mrichter.com/