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Hi, Steve,

The Ampex patent has in its claims both 50 and 54 °C. That was where the 
higher temperature came from. It is still well below the Tg of the base 
film. (67 - 81 °C) 
(https://en.wikipedia.org/wiki/Polyethylene_terephthalate)

Ampex patent here:
http://www.richardhess.net/restoration_notes/USP5236790.pdf



On 1/28/2016 4:10 PM, Steve Greene wrote:
> I used to bake 15" quad reels with a high degree of success at 120F for 24
> hours, with a long ramp down time of another 24 hours before handling it.
> Knowing what I know now, I might go as high as 125F. 54C (130F) seems high
> to me.
>
> Steve
>
> Steve Greene
> Audiovisual Archivist
> Nixon Presidential Library and Museum
> National Archives and Records Administration
> (301) 837-1772
>
> On Wed, Jan 27, 2016 at 8:38 PM, Corey Bailey <[log in to unmask]>
> wrote:
>
>> Hi David,
>>
>> My experience with baking 2" tapes comes from my experiences at Warner
>> Bros. Studios, Burbank, CA. As Richard Hess said: "456 is the poster child
>> for SSS" so, don't ask, just bake it.! Regarding the question of how long
>> to bake is dependent on the size and type of oven, the number of tapes to
>> be baked at one time and (obviously) the condition of the tapes themselves.
>> The oven at WB is commercial grade, capable of baking 34, 10.5" reels at a
>> time. I've baked as few as two reels on up to an oven full. For two reels
>> of 2", the average baking time is 18 - 24 hours. I would suggest that you
>> only bake as many tapes as you can process in a day so that the
>> stabilization process is as fresh as possible. You mentioned leader breaks.
>> Expect any splices to have to be replaced after baking. Not always the case
>> but, build the labor cost into your budget.
>>
>> Cheers!
>>
>> Corey
>> Corey Bailey Audio Engineering
>> www.baileyzone.net
>>
>> On 1/27/2016 8:29 AM, David Crosthwait wrote:
>>
>>> Hello Tom and Richard,
>>>
>>> In my digging through a church archive yesterday with new clients, we
>>> uncovered many reels of 24 track on 2" among other audio tapes. One tape of
>>> interest I have with me, destined to a comrade here in town who is as
>>> passionate about vintage audiotape recovery as we are with videotape, is a
>>> 24 track on "Ampex Grand Master" 456 from 1988 in a cardboard box. It has
>>> track assignments within. The tape has leader breaks. In a test of sorts,
>>> we are going to link this up with a 1" C of the concert (same production,
>>> same date) to create a new stereo mixed version. I've done this before so I
>>> am familiar with the routine. The question to you two (and others) is: What
>>> should we expect from a stickiness standpoint (if any) from 1988 vintage
>>> "Grand Master" 456?
>>>
>>> The client has multiple reels of this concert so this is a test of sorts.
>>> The 24 track will create a ProTools session for the mix down and new stereo
>>> imaging (5.1?), to be done at the client's facility. I'm going to be
>>> remastering the 1" C today to file (it too is in stereo albeit with weak
>>> L-R imaging as viewed on the phase scope). It's a full orchestra with choir.
>>>
>>>
>>> Thank you.
>>>
>>> Best Regards,
>>>
>>> David Crosthwait
>>> DC Video
>>> Transferring NTSC, PAL&  SECAM Two Inch Quad and Helical Source Tapes
>>> (and More)!
>>>
>>> http://www.dcvideo.com/what-we-do
>>> [log in to unmask]
>>>
>>> www.dcvideo.com
>>>
>>> Follow DC Video on Facebook: https://www.facebook.com/dcvideo
>>> Follow DC Video on YouTube: http://www.youtube.com/user/dcvideoonline
>>>
>>>
>>>
>>
>
-- 
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.