Consolidating chalkboard

Susan Russick <susan-russick<-a t->northwestern< . >edu> writes

>We are anticipating the accession of a green colored chalkboard
>(about 4 feet x 6 feet) featuring a multitude of economics equations
>in chalk by a Nobel laureate professor.  We would like to
>consolidate the chalk to retain the writing.  ...

Have you thought of spraying the board with an alcohol solution of
mastic (aka mastiha)?  Mastic (or mastiha) is a natural resin coming
from a tree called mastic tree that only grows on Chios island,
eastern Aegean Sea, Greece.  Mastiha comes out from the sap of the
tree in the shape of tear drops-different sizes are of different
hardness.  Diluting mastic (mastiha) resin in ethyl alcohol has been
used for centuries as a natural varnish.  I have used it as an art
student to consolidate chalk drawings on paper, so I guess this
could work for chalk on board too.  The same material is also
traditionally used as a varnish for icons.

For more information on the material see

    <URL:http://www.gummastic.gr/index.php?contentid=76&langflag=_en>

It is from the cooperative of mastic producers.  It is natural and
inexpensive, and reversible in ethanol or acetone.

Evangelia Kyriazi, MSc
Conservator of Antiquities and Works of Art,
Adjunct conservation lecturer
Technological Educational Institute of the Ionian Islands
Direction of Conservation of Cultural Heritage


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                  Conservation DistList Instance 28:2
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