I know you think it's metal, but you can do a quick check to
see if it might be glass.
Just hold it up to a strong light in the same way you check an
open-reel tape to see if it is polyester or acetate. If you
can see the light through the disc, it's glass.
This would at least allow you to confirm or deny another
possibility. Glass discs often have a fiber or metal inner
disc, surrounded by a glass annulus. So if you identify the
substrate as metal by looking at substrate at the spindle hole,
you are getting a false positive on the metal substrate.
On the other hand, if you are looking at the edge of the disc
and see metal, then it is in all likelihood a metal substrate.
How thick is the disc?
Eric Jacobs
The Audio Archive, Inc.
tel: 408.221.2128
fax: 408.549.9867
mailto:[log in to unmask]
http://www.TheAudioArchive.com
Disc and Tape Audio Transfer Services and Preservation Consulting
-----Original Message-----
From: Association for Recorded Sound Discussion List
[mailto:[log in to unmask]]On Behalf Of Brandon Burke
Sent: Thursday, September 24, 2009 9:49 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Need help identifying a metal substrate
Thanks for the responses (and details), everyone. As it happens, I tried a weak
refrigerator magnet on it yesterday, thinking that would tell me something, and
it slid right off. Nothing. So I tried with a stronger magnet just now - seriously,
if it was ferrous we would know with this one - but again nothing. Strange..
Other ideas?
Secondary question: Given the different - again, "paint-like" - look of the lacquer
layer, are we still talking about cellulose nitrate or is this something different?
(Mike, I realize you already went into this a bit; suggesting rust, which makes sense,
is a contributing factor. What about the lacquer though..?)
Again thanks,
Brandon
----- Original Message -----
From: "Ted Kendall" <[log in to unmask]>
To: "Brandon Burke" <[log in to unmask]>
Sent: Thursday, September 24, 2009 9:32:40 AM GMT -07:00 U.S. Mountain Time (Arizona)
Subject: Re: [ARSCLIST] Need help identifying a metal substrate
Probably steel - beware rust...
----- Original Message -----
From: "Brandon Burke" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, September 23, 2009 11:46 PM
Subject: [ARSCLIST] Need help identifying a metal substrate
> All,
>
> A lacquer came through the lab this week that seems much heavier than any
> I've ever seen. It clearly has a metal substrate but I can't imagine that
> it's aluminum, owing to its being 1 lb 6 oz. Any idea what it might be?
>
> I posted some images to the AAA Board that may or may not help with
> identification. (Hoping that the strange paint-like quality of the nitrate
> layer and its NBC stock will prove illuminating.)
>
> Link: http://arsc-aaa.invisionzone.com/forums/index.php?showtopic=535
>
> thanks,
> Brandon
>
> --
> Brandon Burke
> Archivist for Recorded Sound Collections
> Hoover Institution Archives
> Stanford University
> Stanford, CA 94305-6010
> vox: 650.724.9711
> fax: 650.725.3445
> email: [log in to unmask]
>
--
Brandon Burke
Archivist for Recorded Sound Collections
Hoover Institution Archives
Stanford University
Stanford, CA 94305-6010
vox: 650.724.9711
fax: 650.725.3445
email: [log in to unmask]
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