Re: [ARSCLIST] Ampex 456

[Tom Fine <tflists@xxxxxxxxxxxxxxxxxxx>]

Another interesting point in this thread is the gentleman from Norway saying that despite constant 
temp/very low humidity storage, SSS rear its head reliably. Richard Hess has speculated and 
researched a lot about this topic. As I understand it, it's not clear that SSS is a purely 
ambient-humidity mechanism and may indeed have nothing to do with moisture. I'd like to know, has 
anyone ever done detailed analysis of the "goo" on a sticky tape and compared its makeup to the 
binder material on unstuck or baked tape? I'd like to know if this is some sort of gas reaction with 
some chemical in the binder, leading to a foaming action, rather than having to do with H2O levels 
in the air. Hey, I don't pretend to know chemistry beyond 10th grade regents course, so please let 
me know if I'm speculatin' out my butt.

-- Tom Fine

----- Original Message ----- 
From: "Parker Dinkins" <parker@xxxxxxxxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Friday, June 16, 2006 6:12 PM
Subject: Re: [ARSCLIST] Ampex 456


> Agreed. I have Bill Lund's notes on this subject for an AES presentation he
> made, and his recommendations are largely consistent with a Quantegy
> engineer's recommendation who contacted me several years ago.
>
> I can only guess that the 64 hours and 40 hours suggestions for baking time
> are for food dryers or some other low wattage device.
>
> When confronted with the much larger mass of the 2" tapes, low wattage
> devices might well take much longer to reach the desired temperature. A good
> convection oven with steady air movement that reaches and maintains the
> proper temperature shouldn't take 64 hours.
>
> I routinely used to treat up to fourteen (14) 2" reels of Ampex tape for ten
> (10) hours with excellent results, all at one time. There were spaced with
> 1/4" hubs for improved airflow. That's something like 140 pounds of tape.
>
> And the tapes I treated were stored in New Orleans, where there is plenty of
> moisture.
>
> ---
> Parker Dinkins
> MasterDigital Corporation
> CD Mastering + Audio Restoration
> http://masterdigital.com
>
>
>
> on 6/16/06 4:05 PM US/Central, Tom Fine at tflists@xxxxxxxxxxxxxxxxxxx
> wrote:
>
> > Bill Lund, formerly of 3M, and a tape chemistry expert, suggests 12 hours
> > bake, 12 hours cool to
> > room temp before playing. I trust Bill and have used that method successfully
> > numerous times.
> > Earlier experiments with shorter times were not residue free but did result in
> > playability.
> >
> > No offense to the LOC, but Bill actually worked at 3M and was involved with
> > figuring out what was
> > wrong with Scotch 226.
> >
> > -- Tom Fine
> >
> > ----- Original Message -----
> > From: "Robert Hodge" <rjhodge@xxxxxxx>
> > To: <ARSCLIST@xxxxxxxxxxxxxxxx>
> > Sent: Friday, June 16, 2006 10:09 AM
> > 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.