Reversibility of Paraloid B-72

Tietjen <lena-t [at] gmx__de> writes

>I am working on a bronze object that has been consolidated with
>Paraloid B-72 three years ago. This is my Diploma- project for
>Object conservation at the Fachhochschule fuer Technik und
>Wirtschaft in Berlin. I am asking myself now, if someone has
>experienced that Paraloid B- 72 is not soluble after a certain
>period of time. Although Paraloid does hardly change with time, it
>might get irreversible after 10-20 years. Has someone tried to
>dissolve Paraloid after more than 10 years?

On several occasions I have dissolved B-72 which had been applied to
wall paintings for considerably more than ten years, and in fairly
hostile environments. The most notable examples were: (a) a wall
fragment with "temporary" roofing, but otherwise exposed--over
twenty years after application (b) a vault in a subterranean room
subject to high humidity and water infiltration--over twenty years
after application

My most recent experience was wall paintings in a church which had
been treated with B-72 and probably B-67 thirty-four years
previously. In all cases the resins dissolved fairly readily using
acetone, xylene or a mixture of the two.

Mark Gittins
C.B.C. Conservazione Beni Culturali
Viale Manzoni, 26
Rome
Italy


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                  Conservation DistList Instance 21:9
                   Distributed: Friday, June 8, 2007
                        Message Id: cdl-21-9-002
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