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Re: [ARSCLIST] Ampex 456
We've done lots of 2" and the timing you have is not far off. In fact, it
may be conservative for badly hydrolyzed tapes (though, we "bake" at
slightly lower temperatures).
Cool-down times are not, however, equal to "baking" times. To be done
safely, the tapes are ramped up, held at a constant temperature (Baked or
incubated) and then cooled down. We have found some extremely hydrolyzed
tapes that required over 120 hours of "baking" but ramp-up or cool-down has
never required more than 24 hours.
Peter Brothers
President
SPECS BROS., LLC
(973)777-5055
www.specsbros.com
Restoration and Disaster Recovery Service Since 1983
> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:ARSCLIST@xxxxxxx]On Behalf Of Robert Hodge
> Sent: Friday, June 16, 2006 10:09 AM
> To: ARSCLIST@xxxxxxxxxxxx
> Subject: Re: [ARSCLIST] Ampex 456
>
>
> Hi,
>
> I suspect that due to the increased surface area of your tape, you
> would have to increase the baking time normally used for 1/4 inch tape.
>
> Library Of Congress recommends 8 hours at 130 degrees for pre 1975 and
> 5 hours at 130 degrees for post 1975 and later for 1/4 inch tape.
> I've never baked 2 inch , but this is the path I'd follow unless
> someone has done it differently with success.
> 64 hours at 130 pre 1975 and 40 hours 130 for 1975 and later.
> ( Seems like a lot. ) But the math indicates it so. And the same
> amount of time for cooldown which is equally important..
>
> Best of luck !
>
> Bob Hodge
>
> Robert Hodge,
> Senior Engineer
> Belfer Audio Archive
> Syracuse University
> 222 Waverly Ave .
> Syracuse N.Y. 13244-2010
>
> 315-443- 7971
> FAX-315-443-4866
>
> >>> arclists@xxxxxxxxxxxxxxx 6/16/2006 8:42 AM >>>
> At 06:51 AM 6/16/2006, Lars Gaustad wrote:
> >Hi,
> >I have got a 2" Apmex 456 that is really sticky.
> >I has been stored at 8 C 35% RH for 8 years,
> >which makes me believe that the stickyness is not related to
> hydrolysis
> >(SS),
> >as such storage should rejuvenate the tape just as well as baking
> will.
> >
> >Any suggestions?
>
> Baking should still rejuvenate it if past history is any guide. I'm
> looking for a good explanation of precisely why baking works, but
> I've been told by people who understand these things that the
> generally accepted explanation is not the whole story.
>
> There does appear to be mounting evidence that there is interaction
> between the back coat and the oxide binder system. Again, no answers
> at this time.
>
> I'm not being mysterious, I'm slowly studying this.
>
> Thanks for a really useful data point.
>
> Many of the people working on this are not on this list and I'm
> taking the liberty of passing on your observations to them.
>
> Cheers,
>
> Richard
>
>
> >lars gaustad
> >preservation adviser
> >national library of norway
> >www.nb.no
>
> Richard L. Hess email: richard@xxxxxxxxxxxxxxx
> Aurora, Ontario, Canada (905) 713 6733 1-877-TAPE-FIX
> Detailed contact information:
> http://www.richardhess.com/tape/contact.htm
> Quality tape transfers -- even from hard-to-play tapes.
>
>