In the original question Greg said that these were 2" Helically recorded tapes from the 1960's on a SoundScriber - typically these types of recordings were used for air checks or dictation/transcriptions or logging phone calls over very long time periods. I am pretty sure that the base stock would be Polyester and not Acetate.
That said, I would agree that baking is likely not advisable if delimitation is occurring (or even if it isn't with something as finicky as this), at least without a great deal of inspection and work first to try to figure out precisely what is going on and to develop a treatment plan for the specific problem.
Consider - this is polyester that has helical tracks (long ones on 2" tape) moving VERY slowly for recording, that has been stored in non-temperature controlled environment in Alaska for about 40 - 50 years. You can imagine what the material has done over time - now track that with a period device - forget AST or any fancy technology to make sure that the head is where the track happens to be based on the distortion that has occurred. Yikes!
I would definitely not bake these tapes until I tried a whole bunch of other things first.
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On Jul 16, 2013, at 7:54 PM, Tom Fine <[log in to unmask]> wrote:
> Totally agree with Matt on this one. The WORST thing you can do to acetate is make it hotter and drier.
> -- Tom Fine
> ----- Original Message ----- From: "Matthew Sohn" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, July 16, 2013 6:29 PM
> Subject: Re: [ARSCLIST] Conservation question: oxide delamination and consolidation
>> >Whoa - wait a minute.
>>> Isn't binder hydrolysis (sticky shed) totally different than binder delamination? Would you really want to bake tapes with oxide >delamination???? Some tapes may have sticky shed so bad that it appears to be "delaminating" as you play them, but I'm not so sure that >you'd want to bake tapes where the binder is actually flaking off of the tapes just by handling them. I have not yet had to work with true >binder delamination (and hope I never will) but from what I know, that's a totally different animal not to be to confused with sticky >shed!!! (and I've yet to see anyone out there reveal any simple solution to easily fix or stabilize binder delaminated tapes). Just my two >cents. Suzanne if you have more information, please share it!
>>> John Schroth
>> The only binder delamination I have encountered have been on very old acetate-backed tapes. It seems to me that it is a lack-of-humidity problem that may or may not be remedied by placing the tape(s) in a high humidity chamber for a long period of time (think weeks or months) before attempting to play. I would never bake an acetate-based tape.
>> -Matt Sohn