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Hi, Corey,

Here is what the late Peter Copeland says about it in his posthumously 
published guide,

"Sometimes the binder has oozed so much that it sticks the oxide onto 
the back of the next layer, and of course the oxide comes off and you 
lose the recording. This would have happened even if you had tried a
straight playback. The only cure I know is to run from one reel to 
another very slowly and at extremely high tension. The layers then 
separate slowly and tangentially without damage to the oxide; but you 
will need a specially-modified tape deck with servo control of 
slowly-rotating spooling motors, and it may take a day or two for one 
reel to unwind. Do this in a warm room to allow some of the stickiness 
to dry immediately. We have a prototype machine (called “the Grandfather 
Clock”), which supplies warm air to dry a few feet of tape as it crawls 
from one reel to the other."

I had a slightly different understanding of "The Grandfather Clock" from 
the late Peter Copeland. I recall him discussing it with me that it also 
works for the double- and triple-play tapes that are sticking together.

Cheers,

Richard




On 12/7/2016 00:27, Corey Bailey wrote:
> Hi All,
>
> The British Institute of Recorded Sound (part of the British Library)
> devised a clock-like mechanism to very slooowly unwind audio tapes that
> suffer from oxide flaking. The process apparently has some merit. I
> tried shuttling (running the shuttle function at a creep) a small reel
> of 1/4", AMPEX 456 that suffered from this problem and wasn't that
> successful. This was before I heard of the British Library's clock
> mechanism. So, apparently, the slower one can unwind the layers of a
> tape suffering from oxide flaking or shedding, the better. I have often
> wondered if applying a chemical would help this process. Where I had
> access to potential candidates for some experimentation, the corporate
> environment wouldn't allow it.
>
> As far as tape stocks suffering from oxide flaking or shedding:
> I have mostly run across the problem with AGFA, BASF and AMPEX stocks.
> Some early brands (mostly the cheaper ones as Richard pointed out) of
> acetate base tape have given me oxide shedding fits. I have experienced
> oxide shed with Scotch 201 but almost exclusively at the edges of the
> reel (both 1/4" & 1/2"), leaving the modulation intact. Scotch 206 used
> to be the the one formulation that I could count on but no more. I have
> encountered enough 206 in the last few years that has gone SS, that I
> now check the condition of every brand and type of tape.
>
> Regards,
>
> Corey Corey Bailey Audio Engineering
> www.baileyzone.net
>
> On 12/6/2016 6:01 PM, Richard L. Hess wrote:
>> Gary, I liked that you think I can SHED more light on it!
>>
>> On a more serious note, I have no answers--I even have fewer questions
>> to try and get answers.
>>
>> The only bad shedding I've seen have been on Concert and other
>> lower-end tape, although some 201 has been slightly problematic as one
>> of you mentioned. I have yet to experience this with 206, but so far,
>> my 207 seems fine.
>>
>> I just did another 54 reel project and all played fine. But the tape
>> and boxes did not appear to match.
>>
>> There are so many factors, I don't know where to begin. I've asked Ric
>> Bradshaw if he has any thoughts, but he's getting farther away from
>> that phase of his life, and his experience was mostly at IBM on data
>> tape.
>>
>> Just a reminder about a great 3M tape resource:
>> http://www.aes.org/aeshc/3mtapedoc.html
>>
>> Cheers,
>>
>> Richard
>>
>>
>> On 12/6/2016 13:28, Aaron Coe wrote:
>>> I’ve also encountered Scotch 206 tapes de-laminating (oxide layer
>>> separating from the substrate).  I believe these are from the 1970s,
>>> but not sure.  As of right now there is no treatment that I’m aware
>>> of, but I know Richard Hess has been investigating it though.
>>>
>>> -Aaron
>>> _____________________
>>> http://cuttingcorporation.com
>>>
>>>> On Dec 5, 2016, at 8:57 PM, Gary A. Galo <[log in to unmask]> wrote:
>>>>
>>>> Hi Dan,
>>>>
>>>> I'm sure Richard Hess can shed further light on this, but my
>>>> experiences with tapes in the Crane Recording Archive is that the
>>>> sticky-shed tapes are not the ones that are shedding oxide (by
>>>> "delaminating" I assume you mean that the oxide is peeling off the
>>>> tape). My entire analog career at Crane was on Ampex tape, mostly
>>>> 456, but also some 406, 407 and 457. None of those that I've baked
>>>> and transferred have oxide shedding problems.
>>>>
>>>> The worst offender in our archive, for the problem you describe,. is
>>>> probably Scotch 201 from the mid-late 1960s. 201 was 3M's last
>>>> acetate formulation and it's one of the most problematic tapes I've
>>>> encountered. But, being acetate, you don’t EVER want to try baking
>>>> it. Besides, the only tapes requiring baking are back-coated tapes,
>>>> and none of those are acetate, as far as I am aware. Most of my
>>>> problems with 201 are around splices - the physical cutting of the
>>>> tape seems to have stressed the tape so it's more prone to oxide
>>>> flaking there than elsewhere.
>>>>
>>>> Best,
>>>> Gary
>>>>
>>>> ____________________________
>>>>
>>>> Gary Galo
>>>> Audio Engineer Emeritus
>>>> The Crane School of Music
>>>> SUNY at Potsdam, NY 13676
>>>>
>>>> "Great art presupposes the alert mind of the educated listener."
>>>> Arnold Schoenberg
>>>>
>>>> "A true artist doesn't want to be admired, he wants to be believed."
>>>> Igor Markevitch
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Association for Recorded Sound Discussion List
>>>> [mailto:[log in to unmask]] On Behalf Of Dan Gleich
>>>> Sent: Monday, December 05, 2016 8:00 PM
>>>> To: [log in to unmask]
>>>> Subject: [ARSCLIST] Baking Tapes and Beyond
>>>>
>>>> Dear Colleagues
>>>>
>>>> Over the course of a large digitizing project of mostly 1/4” tapes,
>>>> we have run across a few tapes that will actually delaminate when we
>>>> attempt to play them, in some cases even after the usual low level
>>>> heat treatment that renders “sticky” tapes playable for transfer.
>>>> We have a lot of recordings on Ampex 406, 407 and 456, and 3M 226
>>>> that I expect we’ll need to treat in order to be able to play them,
>>>> but I’m wondering if anyone out there has experience with saving
>>>> tapes that are actually peeling apart.
>>>>
>>>> Any help would be most welcome.  Thanks.
>>>>
>>>> Dan Gleich
>>>> Dan Dugan Sound Design
>>>
>
-- 
Richard L. Hess                   email: [log in to unmask]
Aurora, Ontario, Canada                             647 479 2800
http://www.richardhess.com/tape/contact.htm
Quality tape transfers -- even from hard-to-play tapes.