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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.