Why do good floppy disks go bad?

[Chuck Guzis]

On 04/06/2016 06:00 PM, Paul Koning wrote:

> I have no experience with this issue in floppies.  But I have a
> distressingly large quantity of audio cassettes that have gone bad
> over 10 or 20 years.  It wasn't wear; they weren't played regularly.
> Instead, something bad happened with the structure of the coating so
> that they would squeak loudly when played, both over the playback and
> physically (noisy passage over the head).  The problem is clearly
> incompetent chemical engineering, because it showed up only in one
> brand, which as a result is now on my "never again" list for any of
> its products.

Floppies, tapes, etc. can suffer breakdown in binder, leading to the
dreaded "sticky shed" issue, for which baking is often prescribed.

I've had half-inch tapes suffer from binder "bleed", where the sticky
stuff ends up on the oxide surface and sticks to just about *anything*,
including heads, guides, etc.  Running said tape through a cleaning
machine does next to nothing, other than to cause the tape to stick to
the cleaning blade.

Short term, your friend is D5/cyclomethicone applied as a thin layer and
the tape read immedately (D5 is somewhat volatile and evaporates).

I'll emphasize that my interest is strictly in *reading* and not writing
or re-use of this stuff.

Again, my money's on binder breakdown.  I have lots of samples if
someone wants to investigate further, but the audio tape guys have done
a lot of work on this.

--Chuck