Re: [ARSCLIST] Dry tape squeal problem

["Copeland, Peter" <Peter.Copeland@xxxxx>]

Dear Ed,
    Having used silicone fluids for another purpose (damping the resonances
in disc-recording cutter-heads for LPs), I can conjecture what is wanted,
and I cannot see what harm could be done. (Although, as always, I'd try it
on a section of unrecorded tape first, if you have any).
    I used silicone fluid from a company called Midland Silicones here in
Britain, which was available in various viscosities (that is, internal
frictional stiffness). I usually used 60 centistoke, and when resonances
weren't sufficiently controlled, 200 centistoke. For reducing dry tape
squeal, I would say that you would need something less viscous - say about
20 centistokes.
    The fluid is quite difficult to keep in place - it would "soak into" the
magnetic oxide of any magnetic recording tape - so I would advise you only
to use it on tapes of your own property, and then to get the sound off as
quickly as you can.
    Both aims might be served by the invention of Marie O'Connell and Noel
McGinnity of the National Sound Archives of New Zealand
<moconnell@xxxxxxxxxxxxxxxxxxx>. She used an intravenous drip bag to coat
the tape as it played on a Studer B67. In her case, she was attempting to
deal with the more-usual type of "sticky tape" using isopropyl alcohol; but
I cannot see why the same idea should not be used for silicone fluid. This
was made feasible - with Kiwi ingenuity at its best - by running the tape
across a car windscreen-wiper blade before it reached the takeup reel!
Peter Copeland

-----Original Message-----
From: Edward A. Falk [mailto:falk@xxxxxxxxx]
Sent: 24 January 2003 17:15
To: ARSCLIST@xxxxxxxxxxxx
Subject: [ARSCLIST] Dry tape squeal problem

Hi all; I'm involved in an audio restoration project.  In 1999 there
were some messages on this list about the problem, but I haven't
been able to find any definitive answers.

Note that "dry tape squeal" is not the same as sticky-shed.  Dry
tape squeal happens when the tape's original lubricant has dried up
due to age.

Is there any approved process to re-lubricate a tape?  I'm loathe
to go out and buy any random silicone libricant or whatever and
start spraying.

There was an article out of the library of congress

  http://www.unesco.org/webworld/ramp/html/r9704e/r9704e11.htm

which says to apply a "silicone solution or Krytox" but I'm not entirely
sure what this even means.  (Krytox is an entire product line from DuPont.)

Can anybody tell me what the approved solution is?

ADVthanxANCE,

        -ed falk


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