Re: [ARSCLIST] Record Gunk

[Brandon Burke <burke@xxxxxxxxxxxxxxxxxxx>]

> And hope that cleaning the disc doesn't reveal
> flaking of the lacquer coating.


I think the above point could use a little more explanation.  
Instantaneous discs are not solid like vinyl or shellac. Instead,  
they involve a nitrocellulose layer that is adhered to either an  
aluminum, glass, or paper substrate. (Your example, i agree, is  
likely aluminum.)

In any case, you're going to want to examine the surface of the disc  
VERY closely and under GOOD light to determine whether or not there  
are cracks -- i mean tiny cracks -- in the cellulose layer before  
applying any liquids whatsoever as a cleaning agent. Allowing a  
liquid to seep into a crack in the cellulose surface compromises the  
adhesive and invites delamination.


Brandon Burke



On Oct 4, 2006, at 12:37 PM, David Lennick wrote:

> Christie Peterson wrote:
>
> > We have a 33 1/3 rpm record from 1958 with what can only be  
> > described as
> > white gunk all over the surface.  I'm looking for diagnoses and/or
> > advice about what to do with it (other than don't play it, which is
> > impossible in its current condition anyhow).
> >
> > I've posted pictures here:
> > http://abacus.bates.edu/Library/aboutladd/departments/special/ 
> > Disc.jpg
> > http://abacus.bates.edu/Library/aboutladd/departments/special/ 
> > GunkUpClose.jpg
> > http://abacus.bates.edu/Library/aboutladd/departments/special/ 
> > Sleeve.jpg
> >
> > We rubbed a small amount of the stuff off from the blank surface near
> > the label (visible in the pictures).  It came off fairly easily,  
> > and had
> > a waxy texture.
> >
> > This disc has been stored alongside a number of others that are all
> > fine, so I'm guessing this is something to do with the initial
> > manufacturing process, but not sure.  Based on the label, I  
> > wouldn't be
> > surprised if this was some sort of instantaneous recording disc.
> >
> > Thanks!
> >
> > --
>
> Does it feel as if it has an aluminum base and does it have at  
> least one extra
> hole visible under the label (possibly 3)? If so, it's definitely an
> instantaneous disc and these often turn white, from palmitic acid  
> exuded from the
> lacquer coating. Windex (original, Blue, no generic imitations)  
> works on
> these..try some on a blank portion of the disc if there is one.  
> Shpritz on, wipe
> off, rinse with distilled water. And hope that cleaning the disc  
> doesn't reveal
> flaking of the lacquer coating.
>
> Wrote this before looking at the image..if I had, I'd have seen the  
> word
> "Soundcraft" on the sleeve behind the disc, which confirms  
> everything I wrote
> above. Soundcrap discs are notorious for this stuff.
>
> dl