By the way, 3M is still very much in business.  See http://www.3m.com/.

John Haley

On Fri, Apr 5, 2013 at 2:23 PM, Tom Fine <[log in to unmask]>wrote:

> I think Dennis is bringing up a really important point. Sarah and Richard,
> do you have any contacts with original tape manufacturer chemists, people
> who were familiar with the "brew" of the tapes? Before these people die,
> it's important to get information from them about what chemicals were used
> in the binders. There's no "state secret" anymore -- all of those tape
> manufacturers are out of business now (and I'm afraid, given how things
> work, that corporate records detailing the "brew" are probably lost to
> time). One rumor that's widely circulated is that sticky-shed stems from
> American manufacturers losing access to whale oil, so something else had to
> be used in the binder and unintended consequences ensued. I've also seen
> this rumor denied by former 3M employees, but I don't think those people
> were actual tape-brew chemists. It would be helpful to know these facts.
>
> On a related line of inquiry, there should be research about storage of
> non-sticky tapes. My own first-hand experience with acetate and early
> polyester tapes is that if you store them in too dry an environment, the
> edges curl and the acetate tapes become very brittle. I can state
> first-hand that you can improve playback on an acetate tape that isn't
> vinegar-syndrome but is edge-curled by b-winding it (oxide out) and letting
> it sit in a cool, somewhat humid but not wet environment for a few months,
> then returning it to a-wind and playing it. I've had good luck with this
> method with quarter-track acetate tapes, often able to make the left
> channel mostly playable without extreme measures like putting gauze in the
> play-head can. All of this backs up my theory that the very-dry storage
> conditions recommended for sticky-era tapes are not appropriate for older
> tapes and hasten the complete disintegration of acetate tapes because they
> dry out and become so brittle that the oxide flakes off. As I've said
> before, I haven't seen any science saying that super-dry storage conditions
> has any effect on sticky-shed, the tapes still need baking and still go
> back to sticky after they've been baked. So why ruin other tapes in an
> ineffective attempt to "preserve" sticky tapes?
>
> -- Tom Fine
>
> ----- Original Message ----- From: "Dennis Rooney" <
> [log in to unmask]>
> To: <[log in to unmask]>
> Sent: Friday, April 05, 2013 1:01 PM
>
> Subject: Re: [ARSCLIST] Sticky SHRED
>
>
>  Unless I have overlooked an important post on this topic or am
>> misunderstanding something, what I find missing in this discussion is
>> any comment on the number of different oxide formulations by both age
>> and manufacturer that have been investigated with respect to binder
>> hydrolysis. We know from experience that the phenomenon affects
>> preponderantly those tape types manufactured after 1975, Earlier
>> formulations exhibited other problems but were stable with respect to
>> binder hydrolysis. If my surmise is correct, there is much further
>> study to be carried out on the problem in order to discover
>> preservation and playback strategies that are more than anecdotal..
>>
>> DDR
>>
>> On Thu, Apr 4, 2013 at 4:40 PM, Sarah Norris <[log in to unmask]>
>> wrote:
>>
>>> Hi, Tom (and list):
>>>
>>> Please find responses below:
>>>
>>>  Would you, for us non-scientists on the list, summarize Bradshaw's
>>>>
>>> thinking and the opposing view(s)?  Please try to keep it in the realm
>>> of what an English major or at least what a MLS major can comprehend.
>>>
>>> A more thorough description is in my post from April 2, but here's a
>>> very abbreviated summary:
>>>
>>> Bertram / Cuddihy's model says baking works because it repairs the glue
>>> that holds the media together.
>>>
>>> Bradshaw / Bhushan's model says baking works because it makes the media
>>> and other degraded fragments hold hands for awhile.
>>>
>>>  Do any of the theories you explored about what causes sticky-shed
>>>>
>>> reveal why baking times would be increasing as the tapes get older?
>>>
>>> The models summarized above answer the question, "Why does baking work?"
>>> The question we're asking now is something closer to, "How are tapes
>>> aging?"  I think the first question probably is relevant to the second
>>> question, but probably not in a direct, straight-line kind of way.  It
>>> makes logical sense that longer required baking times indicate more
>>> advanced degradation.  Is that really the case?  Now might be a great
>>> time for a series of studies, one every few years, comparing required
>>> baking times with degraded binder in tape samples!
>>>
>>>
>>> Sarah Norris
>>> Conservator
>>> Texas State Library and Archives Commission
>>> phone: (512) 463-5446
>>> fax: (512) 463-5430
>>> e-mail: [log in to unmask]
>>>
>>
>>
>>
>> --
>> 1006 Langer Way
>> Delray Beach, FL 33483
>> 212.874.9626
>>
>>