[AV Media Matters] Dry tape squeal...

[Graham Newton <gn@audio-restoration.com>]

There seems to be two types of squeal caused by tape defects...
sticky-shed - the one that responds to baking, and lubricant dry-out
which does not.

The "dried out lubricant" tapes are a real problem to try and play.
I've made up a special head block with only one head between two scrape
flutter filter rollers (both the same diameter) and there is enough room
in the head nest to add some kind of re-lubrication device.

The object of this would be to apply a thin film of very light silicone
oil or some other suitable lubricant as the tape passed by, to replenish
the dried out original lubricant.  This could be done from a piece of
block felt or some kind of fabric on which was dripped the lubricant to
keep it saturated as the tape plays.

What I need to know is, what types of lubricant would be appropriate to
use for this purpose.  It doesn't have to permanently bond to the tape
as a "fix" for the dry-out problem, although that would be nice.  It
could simply lubricate sufficiently to get the tape past the head
without the squeal problem, then evaporate.

Does anyone have any ideas or suggestions for this?  What lubricant did
the tape manufacturers use?

... Graham Newton

--
Audio Restoration by Graham Newton, http://www.audio-restoration.com
World class professional services applied to phonograph and tape
recordings for consumers and re-releases, featuring CEDAR processes.