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Richard:

This is an increasingly common problem with a number of video tapes as well.
If, in past postings, you have seen me mention "binder-base adhesion
failure"- this is what we have been calling the phenomena for the last few
decades.

We have seen the problem for a number of years but, recently, there has been
a frightening increase in the number of instances where it is occurring with
VHS, 3/4" and 2" video.  We have seen it in a number of audio tapes, but it
appears to be more prevalent with older video.

One of the first times we saw this problem was over 20 years ago with a
large number of 2" instrumentation tapes that had been stored in a Quonset
hut in the South Pacific.

We have done some testing and tracked down the history on a variety of tapes
that have shown the problem in the past.  From our research, we have come up
with a few scenarios that seem to impact how often BBAF will occur.  Similar
to what Tom speculated, many tapes with BBAF were stored in areas where one
could expect frequent and very extreme shifts in temperature, humidity or
both.

Testing of some tapes clearly shows that the base layer and the recording
layer expand and contract at different rates with changes in either
temperature or humidity.  If the tapes are frequently exposed to extreme
shifts in climate, it is logical to speculate that repeated stresses could
weaken the bond between the two layers.

We have also, but not always, found that this effect is linked with tapes
that are showing some degree of binder hydrolysis.

One interesting observation is that this phenomena is quite common on tapes
that have cinched and folded back upon themselves in the wrap.  If the tape
is stored with the cinch for an extended time, BBAF will frequently occur
where the oxide layer from two adjacent wraps is touching.  When the tape is
straightened out, the recording surfaces that were touching simply fall off
the tape in a sheet.  Frequently, BBAF is not a problem on the rest of the
tape.

Final comment- we developed a procedure to deal with binder-base adhesion
failure about 10 or 15 years ago.  Unfortunately, the procedure takes a few
months and is only successful about 60% of the time.

With the work in tape restoration and recovery we have done over the last 23
years, we consider binder-base adhesion failure to be a much more serious,
though less frequent, decay problem than binder hydrolysis.



Peter Brothers
President
SPECS BROS., LLC
(973)777-5055
www.specsbros.com

Restoration and Disaster Recovery Service Since 1983

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]]On Behalf Of Richard L. Hess
> Sent: Friday, March 31, 2006 11:01 PM
> To: [log in to unmask]
> Subject: [ARSCLIST] Delaminating tape article
>
>
> I thought you good folks would enjoy the latest adventure in cassette
> purgatory. DELAMINATION.
>
> I invite your comments.
>
> http://richardhess.com/notes/2006/03/31/project-notes-advanced-oxi
de-delamination-of-a-cassette/

Is this what we can expect in years to come? Any idea of the cause?
Benoit? Bill?

Hopefully this is a one-off.

Cheers???

Richard

Tape Restoration Seminar:    MAY 9-12, 2006; details at Web site.
Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information: http://www.richardhess.com/tape/contact.htm