Your research is interesting. The one comment I can make is that you
need to allow more time for both the low temp. & and the desiccant
processes. You didn't say just how you protected the cassette while
freezing but, if you were able to play it the next day, you must have
done it right. The earliest research on Binder Hydrolysis indicated that
reducing the temperature and humidity to about 18 Degrees Celsius and
about 24% Relative Humidity for, at least, 3 Months will actually
reverse the problem. No mention was made about long term stability so I
would have to assume that problem tapes would need to be stored in those
conditions. I would think that the desiccant process would need a
similar amount of time to be 100% effective if 100% effectiveness is
achievable using thedesiccant processes. However you are on the right
track and some experimenting with the time it takes to make the cassette
playable would would be most interesting. Please keep us posted. If the
details are too boring for the list, please contact me directly via my
Corey Bailey Audio Engineering
On 4/7/2018 9:46 AM, Eero Aro wrote:
> Hi All
> The red labeled BASF LH Super Compact Cassette tape is suffering from the
> soft binder syndrome. Yellow, orange and green labeled LH Super cassettes
> don't seem to have the same problem, so they must contain other type
> of tape.
> I have been experimenting with the red labeled LH Super cassettes.
> The cassettes start squealing in the deck after less than a minute's
> playback. They
> squeal equally in single and double capstan decks. Cleaning the heads
> and the tape
> path helps for another minute of playback or so. The squealing causes
> modulation and
> disturbing sounds in the audio output. The tape needs dehydration.
> However, I don't
> happen to have a tape baking dehydrator at the moment.
> I first tried freezing a cassette in the deep-freezer in - 18 degrees
> In the morning the tape played without squealing for about five
> minutes. Better
> than the less than a minute without any operations.
> I have seen suggestions that the complete deck should be put in the
> fridge as well,
> but I wouldn't like to do that.
> I decided to try silica gel bags. I did two different versions. In the
> first I put a cassette
> into a small plastic box and padded it in between silica gel bags. In
> the other, I removed
> the tape from the cassette shell and put just the tape in between the
> silica gel bags.
> As untreated, the non-squealing playback time of these two cassettes
> was about two
> The complete cassette that had been in the silica treatment played for
> about five
> minutes without squealing.
> The tape that had been removed from it's shell played for 12 minutes
> after one night
> between the silica gels. After four nights silica treatment the tape
> played for 35
> minutes without squealing.
> Before each playback attempt I had cleaned the heads. The deck wasn't
> before the test to prevent it from warming up.
> I think that this may work so well because it's still winter in
> Finland and the relative
> humidity is low. It's about 54% outside right now. As we have the
> central heating on,
> it is even drier indoors.
> Fortunately, my test cassettes don't have any valuable audio content.
> Eero Aro