Oldenburg sculpture with polyurethane reversion

Giancarlo Sidoti <giancarlo.sidoti [at] beniculturali__it> writes

Meghan Thumm Mackey <meghan [at] alumni__princeton__edu> writes

>I would be grateful to hear from anyone who has worked with one of
>the series of polyurethane sculptures by Claes Oldenburg entitled
>Soft Screw. Thirty-one sculptures in this series were cast by Gemini
>G.E.L. between 1974 and 1976, and some of them exhibit "reversion",
>evidenced by the polyurethane becoming sticky and viscous.

Our team worked on polyurethane sculpture with similar problems. We
have obtained significant results consolidating the polyurethane
with hexamethylene diisocyanate 5% in acetone, which re-hardened the
depolymerized polyurethane. You can found more information in our
publication, unfortunately available only in Italian, that you can
ask us for.

This reversal process has to be done either in local ventilation
such as in a spray booth, or the person doing it has to be in an
air-supplied respirator.  The TLV-TWA for HMI is 0.005 ppm and there
is no air-purifying cartridge approved for it unless there is
personal monitoring of the exposure to set a cartridge change out
schedule.  So air-supplied is about the only way to go.

This method was used in Italy whose standards I don't know.  But the
German MAK-TWA is also 0.005 ppm and that is pretty standard around
the world. This is an extremely dangerous chemical and highly
sensitizing.  In no instance should there be any skin contact with
it, either.

Monona Rossol, M.S., M.F.A.,
industrial hygienist
Arts, Crafts andTheater Safety, Inc.
181 Thompson St., #23
New York NY 10012-2586-212/777-0062


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                  Conservation DistList Instance 24:53
                   Distributed: Monday, May 30, 2011
                       Message Id: cdl-24-53-003
                                  ***