Bush Hammering is a mechanical treatment that makes the surface of the Piasentina Stone wrinkled and pimpled. Such processing can be performed with bush hammers of various sizes, and enables the creation of incisions more or less accentuated. The surface maintains the natural colours of the stone, while the incised areas become markedly lighter. The minimum thickness of the slab on which it is possible to perform a bush hammering surface treatment of is 20 mm.
The finish of Piasentina Stone known as "Flamed" results from the use of mechanical processes of sawing and possible calibration of a heat treatment, carried out using a blow torch fuelled with a mixture of oxygen and other gases, which is followed by an operation of water cooling; the abrupt warming and the immediate refrigeration of the Stone provokes a contained fracturing of the surface, that becomes wrinkled and rough-edged to the touch, providing excellent slip-resistance especially for exterior paving. This type of processing enhances the chromaticity of the product, highlighting its typical characteristics such as the underlying grey colour, the areas of brownish red, and the inclusions of calcite veining, if present.
The "Surface Polished Flex" is obtained through a dry processing, i.e. in the complete absence of water. The sawn surface of the Piasentina Stone is worked by hand, using portable tools fitted with grinding disks (with a grain type ZEC 36, or similar), and is polished until a smooth and uniform surface is obtained. The finish is characterised by a variety of microgrooves, the fruit of the grain of the disk and of the direction followed by the tool operator.
A "Sawn Surface" finish of the Piasentina Stone refers to a product on whose exposed surface the marks left by the tools used in processing are clearly visible, i.e.:
- moderate roughness and parallel grooves, where diamond blades are used;
- radial incisions, with different or crossed angles, where circular blades are used.
"Flamed and Brushed" processing combines the heat treatment of flaming, which causes a contained fracturing of the surface to leave a course and micro-edged effect, with a subsequent brushing operation. The final result is a surface with a pronounced orange-peel texture that is soft to the touch, with a light accenting of the typical colours of the Stone.
The polishing operation involves treating the surface with a series of increasingly fine-grained grinding wheels, so as to obtain a translucent matte effect, from the honed finish, and a polished gloss effect, from the polished finish. Following these operations, the surface takes on fuller and darker tones.
Brushing is a surface treatment that is used to complete other working processes. Through the use of a series of brushes, the surface of the Piasentina Stone is worked to achieve the degree of roughness and patina required. The final chromatic effect varies depending on the mode of brushing: the more it is brushed, the more the Stone darkens and takes on a translucent appearance.