Limestone

Fran Gale <fgale [at] prosoco__com> writes

>This question is posted on behalf a Mary Weisert, a sculptor in the
>Midwest who is currently having difficulties working with a local
>limestone that contains clay minerals and fractures easily.
>
>    How do I repair or keep it from fracturing more, a hairline
>    fracture in Cottonwood limestone. I am using hand tools and have
>    encountered several losses of integrity. any assistance would be
>    appreciated.

The application of an ethyl silicate consolidant such as Wacker
OH100 may prove useful in strengthening the stone especially in
reducing the tendency to crack along bedding planes.  The
consolidant deposits silica that binds the particles of the stone.
The method of application will depend very much on the properties
and composition of the limestone especially the stone's absorption
characteristics.   The use of the consolidant may produce a slight
darkening such as a "damp appearance" but this may be minimised
after the surface has been worked with a chisel and allowed to age.
The suitability of a consolidant also depends on what the intended
use for the sculpture and its environment is as localised changes in
properties of the stone may lead to variations in weathering
characteristics down the track.

Jim Mann
Dimension Stone Specialist
Amdel Ltd
35-37 Stirling St.
Thebarton
South Australia 5031
+61 8 84165200
+61 8 84165328
Fax: +61 8 82342760


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                  Conservation DistList Instance 16:9
                   Distributed: Monday, July 29, 2002
                        Message Id: cdl-16-9-005
                                  ***