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Subject: Sculpey modelling clay

Sculpey modelling clay

From: Carla Flack <carla.flack<-a>
Date: Sunday, September 21, 2014
Heather Pigat <heather.pigat<-a t->utoronto< . >ca> writes

>I am seeking advice and insight into long term care (storage,
>display, handling) from those of you who have any knowledge and
>experience with Sculpey modelling clay.

I did my MA research project in polymer clay in contemporary art so
may be able to help although it was a few years ago and the polymer
clay recipes may have changed.  Basically polymer clay (such as
Super Sculpey or Fimo) is highly plasticised PVC with several other
additives depending on the type, colour etc.  The plasticiser is
'baked off' during the baking process making the hard finished

I did several accelerated aging tests to try and determine how
polymer clay would deteriorate and overall it appeared to be a very
stable material when kept in stable conditions.  I would recommend
keeping it in as low light levels as possible as this is likely to
cause the most amount of harm (50 lux and 75uW/lumen) and around RH
55% with standard temperature levels to prevent embrittlement.  In
addition the baked material didn't seem to off-gas (e.g.
hydrochloric acid) although further testing would be advised and if
possible keep the work enclosed to prevent damage to other materials
close by.

I looked at both Fimo and Sculpey and I would say that Sculpey was
the less stable as it was possible to overbake it causing it to burn
and possibly weaken the material.  An artist I interviewed stated
that she preferred it to be slightly darkened and in addition used
the clay in quite a large scale using an internal armature.
Overbaking, using in a large scale and in close contact with other
materials such as metal may again affect the stability however in
good conditions this shouldn't happen.  I would interview the artist
to determine how they used the material and whether there are any
other materials used in the sculpture.

Carla Flack
Sculpture Conservator

                  Conservation DistList Instance 28:17
               Distributed: Thursday, September 25, 2014
                       Message Id: cdl-28-17-001
Received on Sunday, 21 September, 2014

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