LISTSERV mailing list manager LISTSERV 16.0

Help for ARSCLIST Archives


ARSCLIST Archives

ARSCLIST Archives


[email protected]


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Monospaced Font

LISTSERV Archives

LISTSERV Archives

ARSCLIST Home

ARSCLIST Home

ARSCLIST  September 2018

ARSCLIST September 2018

Subject:

very strange/unique decay found on u-matic

From:

lists <[log in to unmask]>

Reply-To:

Association for Recorded Sound Discussion List <[log in to unmask]>

Date:

Mon, 10 Sep 2018 18:14:29 -0400

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (73 lines)

Today I received a ¾” u-matic tape with the strangest damage I have ever
seen and was wondering if anyone else had seen something similar or had an
idea what might have caused it.

We have processed nearly 500, 000 tapes and we do quite a lot of disaster
recovery. I have seen tapes that have been exposed to virtually every
negative influence imaginable (and some not so imaginable) so I was quite
surprised to see something totally new.

The tape:

The tape is a 3M UCA-60 from 1984. The cassette and hubs are white(ish)
plastic and the interior posts/guides and the door lock mechanism are made
out of black plastic. The access door is anodized black metal.

The damage:

The tape is entirely discolored where exposed. The discoloration is only
near the edges a few wraps into the tape. I have not spooled the entire
tape yet to determine how far the discoloration continues. The metal
cassette access door shows many small spots of corrosion on the inside of
door where it would be closest to the tape. There is no corrosion on the
outside or the edges of the door. The tops of the metal screws on the back
of the cassette are badly corroded. The entirety of the black plastic tape
guides and black plastic door lock mechanism are very brittle/damaged, to
the point where they are falling apart and partially missing/destroyed.
There is no other indication of damage. The white plastic shell and tape
hubs are intact and clean and the plastic slip pads inside the cassette are
undamaged. There is no staining, no warping, no breakage and no brittleness
anywhere else. Whatever happened, only the exposed tape and the black
plastic tape guides, the black plastic door lock, the inside of the metal
access door and the metal screws were affected. Everything else looks fine.

The damage to the tape “could” be consistent with either exposure to liquid
or heat, but- there is no staining anywhere or damage to the paper label
to indicate liquid contamination and there is no brittleness or
deformation/melting anywhere else to indicate exposure to high heat. The
overall damage is not really consistent with either liquid or high heat
damage. I even considered the unlikely possibility that the tape was
contaminated with some corrosive element during playback/rewind and the
posts were damaged as the tape was wound into the cassette. This could
explain why plastic guides are nearly destroyed and the metal access door
was only corroded inside, near the tape, and nowhere else. This,
unfortunately, doesn’t explain the corrosion on the screws and heavy damage
to the plastic door lock mechanism, however, since neither of these parts
ever touch the tape. The plastic hub flange and slip pads inside the
cassette, which do contact the tape, are also undamaged.

Ok, how about some highly corrosive gas that reacts very aggressively with
one specific type of plastic (the guides and door lock mechanism) and
uncoated metal (the screws) but doesn’t react at all with any of the other
plastics in the shell/ hubs/slip pads and/or with anodized metal and reacts
differently with the plastics in the tape (or maybe the metal in the tape?)
in such a way as to produce a byproduct that corrodes nearby anodized metal
(the inside of the cassette door) but dissipates quickly (so the rest of the
anodized cassette door is unaffected). Sound crazy? Yes it does. The
damage is so very specific and selective that I can’t figure out what could
have happened.

Any ideas? Magic? Space aliens?

A very perplexed


Peter Brothers
SPECS BROS., LLC
973-777-5055
[log in to unmask]
Audio and video restoration and re-mastering since 1983


 

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

March 2024
February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
November 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003

ATOM RSS1 RSS2



LISTSERV.LOC.GOV

CataList Email List Search Powered by the LISTSERV Email List Manager