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> "Peoples, Curtis" wrote:

> I just received a home recording on a Wilcox Gay recorded disc and another
> on a Capitol home recorded disc. They both seemed to be paper based with a
> waxy coating, but I am not for sure. Both are warped and the Wilcox Gay
> has many cracks throughout the waxy surface.
<snip>
> What is the best way to flatten these recordings? Further, because of the
> cracks, what is the best way to transfer these recordings? Can I use a
> conventional turntable and clean up the digital file, or would a laser
> turntable work better?
> Also any information about the composition of these type of discs is needed.

I have done many of these.

The discs are cardboard based and probably cellulose nitrate lacquer coated,
intended for home recording use.  Some used another type of slow burning
coating in which case they were usually marked as such.

Dry out deterioration and shrinkage of the lacquer causes the fractures,
which often result in grooves that don't properly line up at the cracks.
This is due to non-linearity of the shrinkage.  Depending on how badly the
shrinkage has progressed, the disc may or may not be playable with
considerable difficulty.  You will need a workstation with good editing
ability to piece it together... it is a VERY time consuming process.

You will need a good turntable and arm with widely adjustable anti-skate
and stylus pressures and preferably a fluid damper... the SME-3012-R arm
is ideal for the purpose, and the SME 3009-R arm is also useable.  You will
also need a good selection of stylus sizes and shapes to choose the best
performer from.

Accumulated moisture in the fiber base of the disc causes the swelling
and warping.  The discs will not likely respond well to flattening attempts.
They can be clamped to a flat metal disc for playback using an appropriate
sized thin ring clamp.  Alternatively, if you don't have ring clamps, and
since the discs are thin cardboard, you could carefully tape the edges down
to a metal disc for playback... an old scrap aluminum based lacquer disc
will work well for this.

Playback at 1/2 speed may be necessary, although it becomes very difficult
to assess problems while doing this.

A laser turntable will NOT work at all for these tasks.




... 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.