Rhoplex WS24

Anne T. Lane <alane [at] charlottemuseum__org> writes

>It has been suggested to me to use Rhoplex WS24 as an
>adhesive/topcoat for the application of "permanent" labels to museum
>artifacts, citing its reversibility in acetone and its relative lack
>of toxicity compared to B72, commonly used for this purpose. I am
>curious as to the aging properties of this material, its shelf life
>once opened, and of course its suitability for use on the types of
>objects that one would normally label using B72.

Practical testing of different labeling adhesives for archaeological
materials was recently undertaken by Ellen Carrlee of the Alaska
State Museum, Anna Weiss of the conservation graduate training
program at Queen's, and Samantha Springer at the Cleveland Museum of
Art. Among the labeling adhesive alternatives we tested were
Acryloid WS24 and Rhoplex B-60-A which is widely used as a
replacement for Rhoplex AC33.  As far as I know, there is no Rhoplex
WS24.

Both the Acryloid and the Rhoplex had the advantages of easy
application and cleanup, pure formulation, easy application to bumpy
surfaces and they did not smear inks when used with the paper label
method (espoused by Thomas Braun in his excellent JAIC article Vol
46 No 2 summer 2007).

However, Rhoplex has a rather high pH (more alkaline than any other
adhesive we tested), and both Rhoplex and Acryloid were shown to
corrode metal, yellow with age, and be somewhat difficult to remove
from the artifact. They are water-based and easy to clean up with
water during application, but once they are dry they are not
reversible easily with water, which is a common misperception among
archaeologists and some museum staff. Also worth noting, Rhoplex
cannot be shipped in freezing weather, and our literature search
suggested that the bond of Acryloid WS24 may get weaker with age.
Yes, we do plan on writing up our findings on these adhesive
alternatives for labeling archaeological artifacts.

Ellen Carrlee
Conservator
Alaska State Museum


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                  Conservation DistList Instance 25:11
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