Facing materials for mosaics

On behalf of Kent Severson <KJPSever [at] aol__com>,
Barbara Appelbaum <aandh [at] idt__net> writes

>The problem is a pile of mosaics removed from their original
>locations and stored in a building that subsequently suffered from
>a fire.  The proposed solution is to work down through the pile one
>layer at a time with some kind of sticky facing in an attempt to
>reconstruct them. The tesserae are heavy, so the facing needs to be
>strong.  Does anyone have any experience with sticky facing
>materials?  Kent is curious about various Beva facings or Acryloids
>such as C10LV.

A couple of years ago I worked on the synagogue mosaic floor lifted
from the site of Zippori (Sepphoris), Israel.  The tesserae on this
mosaic were also heavy as much of the original mortar was still
attached.  I don't have my notes with me but, as I remember, the
mosaic was first faced with a plain cotton muslin which was easily
adhered to all the tesserae.  On top of that, another facing of
heavy burlap was applied for added strength.  The large open weave
of the burlap would not have been suitable for the first facing
layer.

For this project the team used a PVA emulsion--actually I think it
was Elmer's glue.  As the adhesive was not solvent based it was
easily and safely used on large surfaces, in hot conditions, with no
real ventilation. The adhesive was softened and removed easily, and
completely, after conservation with distilled water and soft
toothbrushes.  Again, no hazardous solvents were necessary and the
adhesive did not penetrate into the tesserae. The project took a
couple of years and there were no problems with solubility that I
knew of.

Rachael Perkins

                                  ***
                  Conservation DistList Instance 11:77
                  Distributed: Monday, March 16, 1998
                       Message Id: cdl-11-77-001
                                  ***