[net.records] Unwarping a warped record

ml1@homxa.UUCP (M.LAMPELL) (07/16/84)

I have a prized record that is slightly warped (by the sun). I would
like to straighten it out enough to be able to make a tape of it.
Has anyone had any experience doing this? 

My best idea so far is to clamp the record tightly between two pieces
of glass, and put it out in the sun again. Any ideas on what effect
this would have?

					Maurice Lampell
					..ihnp4!homxa!ml1

marcus@pyuxt.UUCP (M. G. Hand) (07/18/84)

The problem is that the vinyl problem is essentialy a super cooled
liked - there is little order to the material, because it was pressed
and chilled.  When it is heated, the molecular chains begin to slide
across one another and gradually arrange them selves in less energetic
positions (ie the material tends to equilibrate).  This means that the warping
is the obvious manifestation of what is going on at a sub-microscopic
scale - the shapes of the groove walls has also deformed. Unfortuantely
you'll never be able to restore your disk to its former glory even if you
actually mangae to flatten it, because the cutting has been degraded.

		marcus hand (pyuxt!marcus)

did@ucla-cs.UUCP (07/18/84)

Putting it back in the sun may embed dirt/dust particles in the grooves
and ruin the record.  The best thing to do is to stack it with your other
records at 90 degrees, and let time take it's course.

Dave
ARPA: did@UCLA-LOCUS.ARPA
UUCP: ihnp4!ucla-cs!did

hgcjr@utastro.UUCP (Harold G. Corwin Jr.) (07/18/84)

I tried this same trick a few years ago, and it worked
pretty well.  Rather than clamping the glass plates,
however, I weighted the package down with large books
to more evenly distribute the pressure.  After letting
it sit on sun-heated concrete for a couple of hours,
I put the whole stack, books and all, on the kitchen
counter overnight to let the record cool slowly.  By
the way, make sure that the glass is CLEAN.  It hasn't
happened to me yet, but I suspect that one could press
dust right into the record this way.

Good listening!

Harold G. Corwin, Jr.
uucp: {ut-sally,ut-ngp,noao,charm}!noao!utastro!hgcjr
arpa: utastro!hgcjr@ut-ngp
mabell: 512-471-4461 X 463
Dept. of Astronomy, RLM 15.308, Univ. of Texas, Austin, TX 78712-1083