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Subject: CFC's and Wei To

CFC's and Wei To

From: Jack C. Thompson <76520.3531>
Date: Saturday, December 12, 1992
In _Restaurator_ (which I'm certain all of you read) about three years
ago, I wrote an analysis of Cunha's report of the state of mass
deacidification.  At that time there were two contenders: Wei T'o and
DEZ.  That is still the case.  Read my article for the details ("Mass
Deacidification: A Critical Evaluation of the Cunha Report"); I'm at
home as I write this and my copy of the article is at the lab, so I am
unable to give a more complete citation.  The National Library and
Public Archives of Canada have installed a second and improved mass
deacidification system based on Wei T'o chemistry, which achieves nearly
total recovery for reuse of the unused chemistry.  For mass
deacidification, then, Wei T'o remains ahead of the pack.

I do not have time to read all of the journals which occasionally
publish interesting reports about mass deacidification (only the 30 or
so to which I subscribe), but to my knowledge, only one third party
evaluation of Wei T'o and DEZ has been conducted to date, and that was
by the Japanese.  I had the report translated for the _Restaurator_
article.  The findings were that Wei T'o works well and DEZ does not
work well.

I am as concerned as anyone about the environment.  I have chaired two
solid and toxic waste committees over the years, and currently sit on an
Oregon Department of Environmental Quality committee which is
supervising the dismantling of a wood treatment plant which used
pentachlorophenol for many years; I want my children and grandchildren
to live in good health.

However, when the military is permitted to use CFC's as a solvent; when
usage of CFC's as pharmaceutical lubricants, gauze bandage adhesives and
adhesive removers, release agents for plastic and elastomeric molds,
etc. are already exempt....  These uses consume tens of thousands of
tons per year; Wei T'o consumes less than 10 tons per year.

We can wait for that holistic solution in the sky or we can do what
little may be done with current technology/chemistry to preserve the
record of 19th/20th c. human activity (I am not so concerned about
pre-1800 material).  Although Dr. Richard Smith is a friend of mine, we
have had a congenial argument for some years now, and it is this:
non-aqueous treatments create their own problem in that they increase
the reservoir of deliquescent salts in paper and that increases the risk
of mechanical damage within the sheet.  However, without deacidification
I suspect that the risk is greater and that is why I support
mass-non-aqueous deacidification; it gives us time to find a better

Jack C. Thompson

                  Conservation DistList Instance 6:33
                Distributed: Thursday, December 17, 1992
                        Message Id: cdl-6-33-010
Received on Saturday, 12 December, 1992

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