Things could be much easier (maybe still can) if the major players would 
come forward with their oxide formulations.

During the 1990's, I serviced the QC lab for a local manufacturer of 
magnetic film. I had firsthand knowledge of their entire process. I was 
always dismayed at just how non-precise their oxide formulation was. 
Basically, the ingredients were measured by the scoopful and mixed in a 
55 gallon drum. Liquid ingredients were added from gallon jugs or pumped 
by hand from drums. The mixing drum was never cleaned, that I knew of, 
only disposed of when the dried compound became too thick inside the drum.

Hopefully, the likes of 3M, and other manufacturers of analog tape, were 
more precise.

Holiday Cheers!

Corey Bailey Audio Engineering

On 12/18/2015 11:03 AM, Richard L. Hess wrote:
> Tom,
> It is harder than you think. Work has been done and continues to be 
> done on identifying, the causation, and the remediation.
> Since we have no new tape (only NOS) to play with, controlled tests 
> are practically impossible. One paper I read on potting compound 
> hydrolysis, the experimenters made new batches of the polymer to test.
> Needless to say, that is more difficult with tape, especially when we 
> have anecdotal (at least) evidence that the process control was 
> sometimes sub-optimum. And the looooong time it has been around.
> Cheers?
> Richard
> On 12/18/2015 8:53 AM, Tom Fine wrote:
>> I submit, then, that we don't have a clear understanding of what causes
>> sticky-shed. Since we know that baking makes the tapes playable, knowing
>> the cause may not matter at this point, but it would be good to close
>> the circle. I'm surprised the government hasn't spent more time and
>> money on nailing this down, given how much instrumentation and audio
>> tape is archived. It seems like one of the defense-contractor labs would
>> have the chemistry analysis and science expertise to figure this out. It
>> seems to have something to do with polymer science, as I understand it.
>> But then it may not, since we see that what's essentially the same
>> material (tapes from the same batch, assumed from the same rolled out
>> mass of slurry) may or may not go sticky or may not go the same amount
>> of sticky, under same storage conditions.
>> By the way, there seems to be a similar thing with some brown-oxide
>> acetate-backed tapes and vinegar syndrome. I told the tale of two
>> Audiotape masters made around the same time, but likely from different
>> batches, the A and B side masters of the MLP mono "1812 Overture." The A
>> side tape is badly decayed from vinegar syndrome. It is actually a
>> later-time tape than the B side master because it was mixed at the
>> studio (music master combined with SFX master to create LP master),
>> whereas the B side master is a first-generation recording, edited into a
>> master. Both are Audiotape acetate-backed tapes, which have a track
>> record of not going vinegar. So why did one go vinegar and one didn't? I
>> think it's safe to assume they've been stored together all these years.
>> My experience has been that Audiotape acetate-backed rarely goes
>> vinegar, Scotch 111 variants seem to be about 50-50 and are dependent on
>> storage conditions, Kodak is 100%, and Irish (pre-Ampex) trends more
>> like Audiotape (unlikely to go vinegar unless stored in damp
>> conditions). So again, why? We've talked about different impurities in
>> the iron oxide in any given batch. Might that also relate to
>> sticky-shed, that the impurities in the iron are the actual culprit?
>> Both conditions seem to relate to moisture being pulled into the tape
>> chemistry.
>> Some food for thought, by real scientists. Too bad no one with that kind
>> of expertise can get the time or funding to nail down the real answers.
>> -- Tom Fine
>> ----- Original Message ----- From: "Corey Bailey" 
>> <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Thursday, December 17, 2015 11:23 PM
>> Subject: Re: [ARSCLIST] Interesting sticky-shed data point
>>> Back in the day, I had a few occasions where batch numbers were not
>>> the same with bulk 1/4" (406 & 456) on hubs. Tape that was on reels in
>>> boxes, when purchased in case lots, were consistent.
>>> I've also had Marie's experience with Sticky Shed where the same tape,
>>> from the same batch (Based on the batch #'s from the tape ends stored
>>> with the reels), stored on the same shelf, had different levels (some
>>> with none) of SS.
>>> Corey
>>> Corey Bailey Audio Engineering
>>> On 12/17/2015 7:47 PM, Marie O'Connell wrote:
>>>> When I was in the States I made a largish order of about 1000 reels of
>>>> Emtec 911 open reel tapes.  From memory the boxes contained 20 
>>>> reels per
>>>> box and my immediate boss liked me to record the batch number as part
>>>> of my
>>>> workflow.  Not all the tapes in the boxes were from the same batch.
>>>> We had a situation here where the Mitsui Gold CDR's, shrink wrapped 
>>>> and
>>>> all, not only had pit holes in them on the gold layer, but when you
>>>> opened
>>>> the shrink-wrap and case they were full of dust!.  We sent them 
>>>> back but
>>>> heard that another institution in Asia had complained about the
>>>> pit-holes
>>>> and sent theirs back after opening them.  It appears they were then
>>>> re-shrink-wrapped and we got them!
>>>> The joys of archiving!
>>>> Marie
>>>> On Fri, Dec 18, 2015 at 3:54 PM, Richard L.
>>>> Hess<[log in to unmask]>
>>>> wrote:
>>>>> Tom, what you describe is the theory. I have heard rumours that 
>>>>> was not
>>>>> the case in Opelika. Cases were filled with reels when needed. I
>>>>> suspect
>>>>> that bulk packs were perhaps a bit more likely to be all the same
>>>>> batch.
>>>>> How wide were the jumbos in Opelika?
>>>>> Cheers,
>>>>> Richard
>>>>> On 12/17/2015 9:27 PM, Tom Fine wrote:
>>>>>> I thought the numbers on the box and on the stickers box indicated
>>>>>> batch
>>>>>> numbers and dates of manufacture, indicating that all pancakes in 
>>>>>> the
>>>>>> box were from that batch and date. At least that's how I always
>>>>>> understood 3M and Ampex boxes.
>>>>>> -- Tom Fine
>>>>>> ----- Original Message ----- From: "Lou Judson"<[log in to unmask]>
>>>>>> To:<[log in to unmask]>
>>>>>> Sent: Thursday, December 17, 2015 7:54 PM
>>>>>> Subject: Re: [ARSCLIST] Interesting sticky-shed data point
>>>>>> Tom, is it a documented fact that all (12) rolls (reels or
>>>>>> pancakes) of
>>>>>> tape in a box would be from the same manufacturing/slurry batch? I
>>>>>> never
>>>>>> looked, but it would not surprise me if there were different
>>>>>> manufacturing runs on the same delivery carton…
>>>>>> <L>
>>>>>> Lou Judson
>>>>>> Intuitive Audio
>>>>>> 415-883-2689
>>>>>> On Dec 17, 2015, at 4:38 PM, Tom Fine<[log in to unmask]>
>>>>>> wrote:
>>>>>> Hi Marie:
>>>>>>> This is very strange:
>>>>>>>> I have also had reels of Ampex 456 come out of the same box of 
>>>>>>>> 10 or
>>>>>>>> 20 and
>>>>>>>> purchased at the same time where 1/2 have SSS and the rest are 
>>>>>>>> fine!
>>>>>>> I've never heard of that from anyone else. That would almost 
>>>>>>> seem to
>>>>>>> defy all theories of what causes sticky-shed, because one would
>>>>>>> assume
>>>>>>> by a "box" of tapes you mean a real-deal Ampex case with a batch
>>>>>>> number on it. If that's so, it's really freaky that some tapes 
>>>>>>> in the
>>>>>>> same batch (which I think means the same production run of the
>>>>>>> chemical slurry) would get sticky-shed and others wouldn't.
>>>>>>> I'm not doubting your testimony at all, just saying that is calls
>>>>>>> into
>>>>>>> question what is believed to be the cause of sticky-shed, in that I
>>>>>>> can't see how the binder chemistry could differ within a batch.
>>>>>> -- 
>>>>> Richard L. Hess                   email: [log in to unmask]
>>>>> Aurora, Ontario, Canada                             647 479 2800
>>>>> Quality tape transfers -- even from hard-to-play tapes.