Consolidating wood in vacuum chamber

Vojislav Lukovic <voj [at] eunet__yu> writes

>I am working on a wooden object  (25cm x 50cm x 10cm), badly damaged
>by woodworms. I am going to consolidate it using solution of
>Paraloid B72 in toluene. My intention is to improve penetration of
>solution using air pressure (vacuum, underpressure, superpresure,
>etc.). ...

Having done this before, I would suggest using 5%-10% Butvar B-98 in
ethanol, or ethanol/toluene.  If the wood isn't too friable, then a
vacuum pressure of 25 mm Hg should be fine.  I use a Labconco
chamber with a vacuum pump.  I judge the impregnation to be complete
when the bubbles in the solution are almost gone.  The object is
then placed on rack in a fume hood and allowed to air dry.  The
Butvar has been tested as a consolidant for wood; is less glossy
than B-72, and has a higher glass transition temperature.

There are several good articles on this, the most recent being
"Alvar and Butvar: The Use of Polyvinyl Acetal Resins for the
Treatment of the Wooden Artifacts From Gordion, Turkey" by
Spirydowicz, et al, in Journal of the American Institute for
Conservation, Volume 40, Number 1, Spring 2001, pp. 43-58.  That
article builds upon and re-tests some of the results from the
seminal articles such as Barclay, 1981, "Wood Consolidation on an
Eighteenth Century English Fire Engine", Studies in Conservation 26,
pp. 133-139; Nakhla, 1986, "A Comparative Study of Resins for the
Consolidation of wooden objects", Studies in Conservation 31, pp
38-44.  The Spirydowicz article presents data that will help you
design the best treatment for the object in question.

Paul S. Storch
Senior Objects Conservator
Daniels Objects Conservation Laboratory (DOCL)
B-109.1, Minnesota History Center
345 Kellogg Blvd. West
St. Paul MN 55102-1906
651-297-5774
Fax: 651-297-2967


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                  Conservation DistList Instance 18:38
                Distributed: Thursday, February 10, 2005
                       Message Id: cdl-18-38-005
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