[78-L] Can vinyl be unwarped?

[Steven C. Barr]

----- Original Message ----- 
From: "Robert M. Bratcher Jr." <bratcher at pdq.net>
>I realize this is not for a 78 rpm disc (it's a Kim Clement gospel LP
> from 1983) however the record is badly dished so that I can't play it
> well on the outer track of the first side. My question is can a vinyl
> LP be safely returned to flatness in a household kitchen oven between
> 2 sheets of glass? If so then how can it be done safely? What
> temperature should I use? Where would I get the glass to put the
> record between? Or is there a better way to unwarp a record? I'm open
> to any ideas.....
>
Vinyl records CANNOT be "unwarped" in almost all cases...the "warpage"
is created by the fact that vinyl expands with heat, leaving material with 
"no
place to go" except up or down! Thus, HEATING a "warped" vinyl record
would only produce a MORE warped vinyl record...!

In the case you describe, I would recommend placing a fairly heavy weight
on the centre of the (inverted) "dished" LP. (at "room temperature!)." Note
that this may not work, as the LP may result from a "Pressing problem!"

"Warped" shellac records usually come from poor storage...either "long-
term," while exposed to heat (above usual "room temperature") or both!
In any case, the solution is to re-heat the records until they become
flexible, and then manually "bend them into shape!" I accidentally
discovered this when I inadvertantly left a few 78's on the front seat
of my '58 Impala convertible one sunny afternoon while vacationing in
Florida...result being several NON-flat 78's! However, when I found
them, they were still quite flexible...so I could manually bend them back
to "flatness!"

Vinyl records, however, actually expand at higher temperatures! As one
can well imagine, this process means that the expanded vinyl HAS to go
somewhere! Since the size of the disc can't be changed, the "extra" vinyl
becomes "warps" in the disc. This process is, for all practical purposes,
UN-correctible...there exists NO way (that I know of?!) to "shrink"
vinyl?!

Steven C. Barr