Tracy,

It is a problem we have been having for some time....everytime anyone 
posts they will get a rejected message notice. Ignore it. As you can 
tell from my response your post was received...

joe salerno



Tracy Popp wrote:
> Apologies for cross and/or duplicate posts. Received an error message upon
> submission the first time, so I'll have another go...
> 
> Hello All,
> 
> I have a question on visual identification of, and differentiation among
> shellac, instantaneous and vinyl grooved disks. Are there quick visual and
> non-destructive methods of determining the type of disk?
> 
> I am aware that most instantaneous have three "spindle" holes in the center,
> and one can generally determine that a disk is an instantaneous based on the
> core material (if one can see the core material.) Any other suggested
> methods of quick ID and differentiation - barring cracking the edge of the
> disk to see the material composition? Is gently tapping the disk surface,
> and listening for aural cues about material density an useful practice?
> 
> Thanks for your assistance!
> 
> Best,
> Tracy Popp
> UIUC Graduate Student MLS
>