Perspex

On behalf of Walter Castelijns, Robien E. van Gulik
<teyler [at] euronet__nl> writes

>    For a major exhibition we have mounted posters on water colour
>    paper and put them between two 4 mm sheets of perspex (125 cm x
>    200 cm), so the posters can be viewed from both sides.
>    ... The posters are
>    exhibited at room temperature in an unconditioned space
>    (relative humidity 45 - 50%). About one week before the posters
>    were hung the floor was painted with Oxan floor paint (containing
>    60% white spirit). The smell of paint never quite disappeared in
>    spite of ventilation.
>
>    A few days after the exhibition opened we noticed that in every
>    sandwich both perspex sheets were starting to pull away from the
>    object.

We have a Perspex wallboard for the repair of large format items
such as maps. When it was installed we were told that perspex is
very likely to warp and distort in different environments and is
particularly heat sensitive. Perhaps the mounting of the posters
that you were querying was done at different temperature and
Relative Humidity levels to those in your gallery/display area and
having been moved to this area (with possibly alternative
conditions) the Perspex is warping as a consequence.

Regarding the lingering odour of white spirit there is a trick that
a friend taught me. The smell of paint is neutralised by cutting an
onion (yes, the sort that you eat) in half horizontally across the
bulb and placing each half on a plate with a little water. Sounds
ridiculous but it works!

Jeff Cargill
Archives Conservator
Buckinghamshire Record Office

                                  ***
                  Conservation DistList Instance 12:75
                  Distributed: Tuesday, March 23, 1999
                       Message Id: cdl-12-75-008
                                  ***