Microwave drying

The earliest evidence I have for microwave drying of water damaged
books/records is a 26 page brochure from Amber & Amber, Consulting
Engineers,  Document Reclamation Service, Inc., Box 261, Royal Oak,
Michigan, postmarked Feb 2, 1963.  On p. 15, under the heading
"Electronic Drying" they list: "Dielectric heating, dielectric
vacuum heating, microwave Radar-range drying, ultrasonic heating,
induction heating."  I have never found another reference to this
firm.

George Cunha, in Conservation of Library Materials, p. 213,
mentions the use of microwave, possibly as one element of the
recovery effort after the 1966 Florence flood:

   "Although regular oven drying will do more harm than good, by
    shrinking and distorting book covers and bundles of text,
    because of the extremes of heat between the insides and outsides
    of the wet bundles, microwave ovens are a different matter.  The
    high frequency energy in these devices safely bakes out the
    moisture because uniform temperatures are created throughout the
    wet masses by radiant heat.  All of the commercial
    establishments near Florence which had any sort of drying
    facilities for tobacco, bricks, straw, ceramics, and rice were
    pressed into service in 1966 regardless of the type of heat.  It
    has been recommended that if similar facilities are used again,
    the temperature be maintained at 122 - 140 deg. F and the
    relative humidity at 35 50%, if at all possible."

My one experiment, using a microwave oven to dry wet interleaving
paper, was a failure.  The edges of the pack were warm when the
middle of the pack of wet paper was steaming hot.

Jack C. Thompson
Thompson Conservation Lab.
7549 N. Fenwick
Portland, OR  97217

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                  Conservation DistList Instance 11:40
                 Distributed: Tuesday, October 28, 1997
                       Message Id: cdl-11-40-004
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