[78-L] Glass Records

[Doug Pomeroy]

The glass base is quite thin, and a sudden change in temperature
will cause the glass to expand or contract enough to shatter it.
I learned this the hard way.   Even the warmth of one's hands
may cause this when holding a cold disc!  And any fluids used
to clean and rinse the disc should be at room temperature!

Doug

> Date:    Mon, 17 May 2010 16:49:39 -0700
> From:    "Kevin P. Mostyn" <lists at MOSTYN.COM>
> Subject: Re: Glass Records
>
> I have handled a few thousand glass-base 16" discs in my life.  
> Currently,
> there are about a thousand of these in my garage.
>
> They are extremely fragile. I have seen them break merely by being  
> picked up
> carefully. Once when doing research in the bowels of the LOC, a disc
> shattered in the hands of the person assisting me. He was very  
> experienced
> with such discs (the eponymous Jim Smart), he did everything  
> correctly, but
> it shattered nonetheless.
>
> My advice is to treat them as if they were explosive. Carry only  
> one at a
> time. Try to carry it on a flat sacrificial aluminum base 16" disc.  
> Never
> leave it unsupported. Avoid any situation where it might flex,  
> because it
> doesn't want to flex; it wants to break. If moving a box of them,  
> make sure
> that the box is reasonably rigid and that the contents are  
> protected from
> external forces and that the contents cannot flex.
>
> Although glass has a smoother surface than metal, World War II was the
> reason for its widespread use. Aluminum was declared a war priority  
> item and
> was unobtainable for civilian use. In addition, there were large  
> "drives" to
> solicit donations of aluminum from the public. Vast numbers of  
> aluminum 16"
> disks were donated to these drives (as well as pots and pans), thus
> destroying a large part of our audio legacy. Then there were  
> services that
> would recoat used aluminum discs with fresh lacquer for reuse, again
> destroying more of our audio history. It's a miracle that any  
> survived; it
> also explains why so little of pre-war transcriptions exist. The  
> majority of
> 16" lacquers that I have seen are from 1940 though the mid-1950s.  
> The ones
> from 1934 through 1939 are relatively scarce. Unfortunately, none  
> of "us"
> were around and in a position to do anything about it back then!  
> Libraries
> didn't archive such things.
>
> Lacquer transcriptions were made for various purposes, such as  
> syndication,
> delayed broadcast, verification of commercials that were broadcast,  
> etc. In
> addition, there was a law in America that any shortwave broadcast from
> America had to be recorded. Millions were made over the years, but  
> sadly,
> history has not treated them well. Those that survive are slowly  
> being eaten
> by palmitic acid. It's a lugubrious tale.
>
> --Kevin Mostyn