Araldite

Eleni Loizides <eleni.loizidou<-a t->cytanet< . >com< . >cy> writes

>Our metal conservation lab has been using Araldite AY103 resin and
>HY956 hardener mix for the gapfilling and reconstruction of (but
>also in some cases adhering) archaeological copper alloy artefacts.
>
>We are currently looking into replacing this material as we have
>recently noticed in a couple of instances that the clear resin
>undergoes a colour change upon setting and when in contact with the
>original object surface (it obtains a light blue colour similar to
>azurite). ...

One must be aware that on most cross-linked synthetic resins, copper
ions would migrate quite easily and is the responsible for that
coloration you have noticed.  The phenomenon can be quite rapid and
in most instance, this migration is breaking the linked and
therefore physical stability must be considered as compromised over
time.  One way to get around this problem is to isolate the copper
alloy from the structural or gap filling resin.  This is our
practice for more than two decade with no bad draw back since.
Quoting a specific resin has little sense as is tribute to
availability, conditions and specificities.

One must remember that reversibility is therefore subject to the
isolation compounds used as isolator, so if you choose a solvent
based resin, the only trick you have to dismantle your work is to
use the specified solvent.

Hope this help and do not hesitate to contact me directly for more
developments.

David Cottier-Angeli
Associated Member of the Swiss Chamber of Technical and Scientific
    Forensic Experts
CottierMetal
Geneva
+41 22 300 1955
Mobile: +41 79 319 319 0


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                  Conservation DistList Instance 28:7
                  Distributed: Saturday, July 19, 2014
                        Message Id: cdl-28-7-002
                                  ***