Re: arsclist Vinyl records and blast freezer

["George Brock-Nannestad" <pattac@xxxxxxxx>]

From:           	Jay Gaidmore <JGaidmore@xxxxxxxxxxxxx>
To:             	"'ARSCLIST@xxxxxxxxxxxxxxxxx'" <ARSCLIST@xxxxxxxxxxxxxxxxx>
Subject:        	arsclist Vinyl records and blast freezer
Date sent:      	Thu, 21 Jun 2001 11:31:45 -0400
Send reply to:  	ARSCLIST@xxxxxxxxxxxxxxxx

Jay Gaidmore wrote:


> The Library of Virginia recently acquired a collection of sound
> recordings from a local radio station dating from 1925.  This
> collection includes vinyl records (as large as 18"), cassettes, and
> reel to reel tapes.
> 
> Apparently, the collection is infested with bugs and we are wondering
> if using a blast freezer to kill the bugs is a safe method.

----- It is only safe as far as killing with certainty - there is a grave 
risk that the shock of freezing will destroy certain of the recordings. 
In particular laminated materials, such as lacquer discs (also 
termed acetates) which are two lacquer layers on aluminum or 
glass base, will suffer due to the different thermal coefficient of 
expansion of the two materials. In case the materials are brittle but 
have a considerable heat capacity (certain shellac alloys) the risk 
is basically the same.

Now, bugs I take to be insects. In that case, deprivation of oxygen 
will work well. Put in a pure gaseous nitrogen environment with 
removal of oxygen, for instance by using sealed aluminized plastic 
bags with a minimal excess volume. Before rinsing with nitrogen 
gas and sealing, introduce into the container the type of oxygen 
scavenger which is basically a very finely powdered iron dust (in a 
bag). The name eludes me sitting at the screen, but it was 
developed to avoid rancidness of fatty foodstuffs and is now sold by 
archive supply companies.

In case the infestation is silver fish (eats starch, such as coated 
paper and carton), then liquid treatment with a spray of permethrin 
would do and wipe dry. Permethrin is dangerous to fish but not to 
humans or animals.

In case the infestation is fungii or bacteria, I know that the British 
Library, National Sound Archive (or rather its predecessor) tried to 
use electron radiation (beta rays) with great success. This 
destroys spores too, if I am correctly informed.

I hope that you can use some of the above information.

Kind regards,

George Brock-Nannestad
Preservation Tactics