Joshua,

Mylar may slow down the effect of organic acids from wooden shelves but 
it is not an effective long-term solution.Mylar is not completely 
impermeable and it does allow a small measure of air exchange - - and 
there are also the ends of the boards and the bottoms that will still 
outgass.  If you had a lead or lead alloy object on those shelves they 
could corrode very rapidly - it takes only 0.2 parts per million of 
acetic acid to corrode lead. It would be far better to used a product 
such as wood product such as Medite which is manufactured without the 
organic acids that is in plywood.

Cheers!
Dave

David Harvey
Conservator
Los Angeles, California

-----Original Message-----
From: [log in to unmask] <[log in to unmask]>
To: [log in to unmask]
Sent:         Tue, 10 May 2005 08:17:09 -0400
Subject: Wooden Shelves

    From searching through prior emails, it is my understanding that a 
sheet of mylar (or whatever it may be called today) between objects and 
a wooden shelf is sufficient and no painting or sealing is necessary. 
  Half of the shelves I am working with are metal, the rest are wooden, 
probably pine, boards. 
 
 Thanks very much, 
 
 Joshua K. Blay 
 
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