[78-L] Glass Compound 78s

[Michael Biel]

-------- Original Message --------
Subject: Re: [78-L] Glass Compound 78s
From: 78records at cdbpdx.com
Date: Tue, June 16, 2009 8:41 am
To: 78-L Mail List <78-l at klickitat.78online.com>


> THANKS for all the info about these. Very helpful.
> The link below shows the label of one of the records I am inquiring
> about. You can see an under-label around the edge of the studio label.
> Is that label familiar? 
> http://78records.cdbpdx.com/BCO/tn-800_BCO-07_SentForYouYesterday.JPG

Yes, this is a Presto Green Seal Glass Base disc label.  

> When looking through this record, it is blue, as described. I have
> some records that are stamped GLASS on the label and they are red
> when I look through them. See link below:
> http://cdbpdx.com/78records/Labels/tn-600_RadioRecorders_5-31-44_SeeThru.JPG

I can't see this picture because it is asking for passwords.  But Radio
Recorders was a major Los Angeles studio that did ALL the recording for
CBS on the West Coast and usually had bright yellow labels.  The red
tinge might be AudioDiscs.  Is there a roughness you can see or feel
under the labels at about 2 or 2 1/2 inches diameter?  Does the center
hole look like a fibre base surface?

> I am keeping them in a 10 page record album. Guess I'd better
> make other arrangements for them.  Thanks! CDB

YES!! Having them in an album is the absolute worst way to store them,
except perhaps under the wheels of your car.  Eventually the result will
be the same.

Mike Biel  mbiel at mbiel.com


--- On Mon, 6/15/09, Michael Biel <mbiel at mbiel.com> wrote:

> From: Michael Biel <mbiel at mbiel.com>
> Subject: Re: [78-L] Glass Compound 78s
> To: "78-L Mail List" <78-l at klickitat.78online.com>
> Date: Monday, June 15, 2009, 10:14 PM
> 78records at cdbpdx.com
> wrote:
> > > Greetings. I am wondering how to easily identify
> glass compound 78s.
> 
> I assume you are referring to a glass-base lacquer coated
> recording
> disc.  This is a disc that is a sheet of glass with a
> plastic coating on
> it that the recording is directly cut into.  
> 
> > > I was playing a record from 1942 and I noticed
> the sunlight was sparkling
> > > off the record in a rainbow of color, as if the
> light was being reflected
> > > through a prism.
> 
> This could happen with an aluminum base lacquer disc as
> well because
> that base is reflectively shiny as well, but when you
> describe it being
> translucent you can only be describing a glass base disc. 
> 
> > > I examined the record closely and discovered I
> could see brightly lit
> > > images through it. It has an unfortunate crack
> and the edges of the
> > > crack seem to be flaking off like glass. 
> 
> The lacquer coating can flake off like this from any base
> material,
> aluminum, steel, or glass.  The dark coating is not
> itself glass.  If
> part of the clear glass base is crumbling, then the base is
> more than
> just cracked, it is smashed.
> 
> > > Could this be a glass compound record? Are there
> any sure-fire
> > > ways to identify glass compound records besides
> cracking them
> > > and looking to see if the edges are flaking
> off?  Thanks! CDB
> 
> As dl mentioned, you often -- but not always -- can see
> light shining
> thru the translucent discs.  If you do not want to
> hold the disc up to
> the light, you can shine a strong light up thru it. 
> Once you have
> identified a glass-base disc it should always be stored in
> a sleeve with
> a second aluminum-base disc with it, and the disc handled
> only with that
> second disc supporting it.  Archives with large
> collections of glass
> base discs should have a rule that an aluminum disc be slid
> into the
> sleeve and both discs be taken out together.  I was
> lucky when I worked
> with the NBC Chicago collection at Northwestern to have a
> large amount
> of unimportant aluminum based discs to store with our
> glass.
> 
> As dl mentioned, professional grade discs were not marked
> on the discs
> themselves, only on the sleeves which often can get
> switched so that a
> glass base sleeve could house an aluminum disc, but most
> home-grade
> glass base discs are marked on the manufacturer's
> label.  But glass was
> rarely sold to the home recording market.  They used
> steel base and
> fibre base discs.  Many radio and recording studio
> labels did mark the
> discs as glass, but not always because the labels were
> sometimes
> prepared by a secretary, not the recording engineer. 
> The first glass
> Presto discs were very thick and had a metal grommet in the
> center hole.
> AudioDevices' AudioDisc brand had a fibre-center that was
> about
> 2-inches in diameter, and the edge of how this fits into
> the larger
> glass hole can sometimes be seen or felt.  Later in
> the war Presto had a
> printed label that said glass base, but I am not sure if
> the discs were
> shipped with this label on them or if it was to be applied
> by the user.
> 
> As to whether glass discs were more flexible when new, I
> doubt that
> because one of the reasons glass was used was because it
> was less
> flexible than aluminum.  One of the selling points of
> glass prior to the
> war was that it was ideal for use for mastering because it
> remains
> flatter than metal when being electroplated.  The
> first glass discs were
> shipped in early April 1941, prior to our entry into the
> war, and before
> aluminum rationing.
> 
> Mike Biel   mbiel at mbiel.com
> 
> -------- Original Message --------
> Subject: Re: [78-L] Glass Compound 78s
> From: David Lennick <dlennick at sympatico.ca>
> Date: Tue, June 16, 2009 12:25 am
> To: 78-L Mail List <78-l at klickitat.78online.com>
> 
> Very simple..assuming that it's sturdy enough for you to
> handle without
> it 
> breaking (and those things are VERY thin), hold it up to
> the light. If
> you see 
> translucent bluish, yep..it's glass based. As for the
> flaking, that's
> not 
> reversible.
> 
> If you find this somewhat risky, you can tape the edge
> lightly with your
> ring 
> finger. The sound will be different from tapping an
> aluminum disc.
> 
> Not all manufacturers identified glass lacquers, except on
> the sleeve,
> which 
> was pretty dumb. Amazing that 65 years ago, these things
> were able to be
> 
> shipped..carefully, yes, but they frequently made it
> intact. They must
> have 
> been a bit more flexible when they were new.
> 
> dl
> 
> _______________________________________________
> 78-L mailing list
> 78-L at klickitat.78online.com
> http://klickitat.78online.com/mailman/listinfo/78-l
> 
_______________________________________________
78-L mailing list
78-L at klickitat.78online.com
http://klickitat.78online.com/mailman/listinfo/78-l