Exhibiting vulcanized rubber

Silvia Manrique <silvia.manrique [at] umfa__utah__edu> writes

>We recently acquired a Chakaia Booker sculpture made out of
>automotive tires which we would like to put on a permanent
>exhibition. ...
>...
>...  The artist believes we should apply a coat of
>WD-40 or Armor All on the rubber ...
>...
>We have pretty stable environmental conditions in our spaces,
>usually around 50% RH and 70 deg. F, and low light levels.

The conditions in your gallery are low light levels, but around 20
deg. C and 50% RH under which oxidation of natural rubber is likely
to take place. If you wish to apply a coating, I would advise
against both WD-40 as it will slowly soften the rubber and Armor All
as its solvents swell rubber.  Waxes including paraffin wax and
natural waxes have traditionally been applied to protect rubber
surfaces from reaction with both oxygen and ozone.  I made some
simple experiments in the 1980s which suggested that applying melted
paraffin wax to samples of rubber inner tubes slowed the rate of
oxidation.  However, the resulting film was more brittle than the
rubber and therefore cracked on flexing or stretching. A thin film
of paraffin or other wax would be a safer alternative to
solvent-based coatings.

Yvonne Shashoua
Senior Researcher
Department of Conservation
National Museum of Denmark


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                  Conservation DistList Instance 25:11
                 Distributed: Saturday, August 20, 2011
                       Message Id: cdl-25-11-003
                                  ***