Series editors' preface - Wood Tools

716 Conservation of Furniture
stains have penetrated some distance into the
stone. Solvent cleaning, outlined in 11.3, may
be used for the removal of aged, non-original
coatings. There have been suggestions that
steam cleaning of stone is an excessively
aggressive treatment and current research
should be considered before such a treatment
is undertaken.
Alabaster may be cleaned with non-polar
solvents, although a small amount of alcohol
may be used if a more polar mix is required.
The efficacy of solvent cleaning solutions may
be improved if they are applied in gel form.
Poultices for use on alabaster may be made
with a non-polar solvent and sepiolite or attapulgite.
Consolidation
Stone that requires consolidation should be
referred to a specialist for treatment.
Repair and reintegration
Once a slab has broken it is likely to be more
fragile than a comparable unbroken piece,
regardless of the method used to repair it. The
treatment of major structural repairs will be
dependent on the thickness of the slab and the
type of break. The most common methods used
by stone conservators to support breaks are
stainless steel dowels, cramps or flat rods set
into a thixotropic knife grade polyester resin.
Such treatments should be undertaken by an
experienced stone conservator. Structural fills
for stone, i.e. those that contribute to overall
structural integrity, have been considered by
Griswold and Uricheck (1998). An aluminium
honeycomb support, such as Hexlite ® , may be
used underneath a broken slab to support it.
Such supports offer the advantage of minimal
intervention coupled with a uniform lightweight
support but will change the thickness of the slab
component. Although Hexlite ® is often used in
conjunction with epoxy resins, the use of a
range of other adhesives, including PVAC and
Beva 371, has been described in conservation
literature.
Marble chips may be reattached using a
thixotropic knife grade polyester resin. Fills
may be necessary if small losses have occurred.
Fills may be made using water clear polyester
or two part acrylic resins such as Akemi ®
(Figure 16.1a). The choice of polyester resin
for fills is dependent on the required working
(a)
(b)
Figure 16.1 Infilling marble
(a) An area of loss on a seventeenth century Indian
marble Agrawork panel, prepared to receive a fill.
Aluminium foil tape has been used to ‘wall’ the fill,
which is built up in stages. Water clear polyester resin
has been matched to the colour of the background
marble using alabaster powder and pigment. The
pigmented polyester resin forms a thick but fluid paste
(b) Fill completed and matched to the background
colour of the marble. Although the Agrawork design has
been reproduced where the design elements were
known, conjectural restoration has not been undertaken
time. Ground white alabaster or white marble
dust may be used in combination with pigments
to obtain the required texture and colour
(Figure 16.1b). Melinex/Mylar may be used
between a piece of Perspex/Plexiglass and the
surface to ensure a level fill. An uneven fill
may be levelled using a sharp blade and polished
using fine abrasive papers, but care must
be taken to avoid damaging the adjacent stone
surface. Very small fills may utilize Polyfilla or
pigmented wax. If local retouching is necessary
finely ground pigments in a thin solution (less
than 5%) of a Paraloid resin or other conservation
grade binder may be used. Artist’s