Print

Print


At 10:53 PM 2009-12-15, Mark Campbell wrote:

>Please tell us more about the "grandfather clock" tape recovery machine.

Hi, Mark,

The "Grandfather Clock" was a device developed by Peter Copeland and 
his team at the British Library and was possibly the first concerted 
attempt at unwinding tapes with binder-base adhesion across wraps.

I believe the best reference on it is here:
http://www.bl.uk/reshelp/findhelprestype/sound/anaudio/manual.html
and I do have that linked in my blog
http://richardhess.com/notes/2008/09/14/peter-copeland-audio-restoration-handbook-now-available/

Here is what Peter wrote to ARSCList in 2001 when I was fussing with 
the reel of 3M176

>From: "Copeland, Peter" <[log in to unmask]>
>To: "'Richard L. Hess'" <[log in to unmask]>,
>         "[log in to unmask]" <[log in to unmask]>,
>         "[log in to unmask] Rochester. Edu (E-mail)" <[log in to unmask]>
>Subject: RE: arsclist Scotch 176 adhesion problems
>Date: Fri, 20 Apr 2001 12:08:52 +0100
>
>Dear All, Here at the British Library National Sound Archive we have found a
>total of six double-play and triple-play Agfa tapes showing similar
>symptoms. The oxide adheres to the backing of the next layer, which in this
>case is glossy (not matt). At normal playing-speeds (7 1/2 ips) the oxide is
>completely wrecked in the process, and the tape ruined. Neighbouring tapes
>in the same collections are usually OK, it afflicts (I would guess) one tape
>in five hundred. We are currently using outhoused contractors to get the
>sound off such tapes for print-through reasons. The contractors are all
>mandated to unpeel the outer turn of the tape very slowly, and if the oxide
>shows signs of coming off, return them to us unplayed.
>     You cannot bake such a tape; as Richard Hess says, it's different from
>the usual synthetic polyurethane binder problem. Following an accidental
>discovery on my part, the solution seems to unwind the tape incredibly
>slowly. I understand that what we call "Sellotape" here in England is
>conversationally called "Scotch Tape" in America. If you pull some Scotch
>Tape from the reel fast, it goes "pzzzzip" as it separates, while if you
>pull it slowly it separates cleanly. We have built a prototype machine
>(called a "Grandfather Clock", because that's what it looks like) to unwind
>the tape incredibly slowly. The gearbox ratio can be changed, but at the
>moment the takeup reel turns at one revolution a minute, so a reel may take
>three days to unwind. As this happens, it travels up the grandfather clock
>through a box fed with warm air from a fan to dry it before it reaches the
>takeup reel. But until last week, we hadn't enough examples of such tapes to
>test the machine thoroughly. I hope to present the resulting design at the
>ARSC/IASA conference in London in September.
>Peter Copeland
><[log in to unmask]>



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
Quality tape transfers -- even from hard-to-play tapes.