>From: Michael Biel <[log in to unmask]>
>Sent: Apr 23, 2012 4:22 PM
>To: [log in to unmask]
>Subject: Re: [ARSCLIST] Determining substrate of laquer discs
>It couldn't be easier. A magnet would be attracted to a steel disc.
>Steel discs are definitely heavier than aluminum discs, but except for
>rarely found thick professional grade are not really sturdier than
>aluminum. They tend to permanently bend easier, especially in the more
>common home grade like Wilcox-Gay Recordio and dozens of other brands.
>One other problem is rust. The metal can rust under the lacquer coating
>and create bubbles and loosen adhesion of the lacquer layer.
>Also note if the magnetic pickup you would be using would likewise be
>magnetically attracted to the disc which would raise the tracking
>Mike Biel [log in to unmask]
>-------- Original Message --------
>From: John Dawson <[log in to unmask]>
>> Hi everyone,
>> I was wondering if anyone had tips/resources about determining whether or not a the substrate of a
>> laquer is steel or aluminum. I have some WWII era discs and some are definitely heavier and sturdier > than others. I am wondering if these are steel.
>> John Dawson Indiana University Media Preservation Initiative