Surface
finishing is the treatment that brings out the esthetic
features of the material. The ornamental function
and also some technical characteristics (e.g. its resistance
to wear and weather conditions or its slipperiness)
are strongly influenced by the surface finishing applied
to the product. Depending on the treatment, we
can divide the finishing into mechanical, impact, and
chemical methods. |
|
| |
|
|
| |
|
 |
|
| |
|
 |
|
| |
|
In mechanical
finishing, the stone is put in contact with an abrasive
to reduce the original surface roughness to some extent.
|
[
top ] |
| |
|
Rough
Though infrequent, sometimes the
sawn material or even just-quarried material is ready
for installation and needs only to be cut to size.
The surface in this case is generally rough, with an
uneven face. Rough stone is predominantly used outdoors,
where it is appreciated for its non-slip quality.
It is often used with slate and with some kinds of sandstone. |
[
top ] |
| |
|
Polished
Polishing is the main and the
most frequently applied finish. It follows the finest
honing and employs polishing abrasives that add brilliance
with mirror effect to the stone surface.
|
[
top ] |
| |
|
Honed
This finishing aims to produce a
smooth surface by using abrasives of ever finer grain
on the surface, so there is not a single honing but
a series of progressive degrees of it. Honed finish
is not reflective and makes the color tones slightly
dull, but the treatment preserves the material’s natural
esthetic characteristics. |
[
top ] |
| |
|
 |
|
| |
|
In impact
finishing a strong external force is applied to the
stone surface in order to alter and enhance the original
surface roughness. Because they produce surface
unevenness, these finishes are usually not slippery,
but they do get dirty easily.
|
[
top ] |
| |
|
Brushed
Brushed finish is obtained by applying
hard plastic or metal brushes to the stone surface.
The heavily action removes the softer part of the stone
and wears out the surface, giving it a look similar
to that of antique finishing. |
[
top ] |
| |
|
Brush
Hammered
Bush hammering is obtained by hitting
the material surface mechanically or by hand with a
specific multi pointed tool. This method creates a rugged
surface full of little grazes at the impact points,
and it modifies the color, making it lighter. The surface
becomes non-slip. This technique has been replaced by
flaming and pressure water finishing because these are
faster and less costly. |
[
top ] |
| |
|
Tooled
Tooling is similar to bush hammering
but it is obtained with a larger, single-pointed steel
tool. The chromatic & non-slip effects are
similar to those obtained with bush hammering, but tooling
can applied only to a chosen part of the surface, thus
leaving some rough areas. The effect it produces
is useful in giving stone a medieval character. |
[
top ] |
| |
|
Sandblasted
In sandblasting, a high-pressure
jet of siliceous sand or carborundum or steel shots
is applied to the area to be treated. It produces
a smooth abrasion, leaving the material slightly scratched
on the surface, but not rugged. The color tones
and the veins are a bit dulled. |
[
top ] |
| |
|
Flamed
Passing a blowpipe that emits a high-temperature
flame over the surface to be treated. The heat
acts by blowing the crystals out as they suffer thermal
shock, with an effect that is particularly evident in
materials composed of minerals with various degrees
of expansion, e.g., the vast majority of granites. The
surface produced is rough and non-slip, and the color
is generally faded, hiding defects and tone variations. Because
of oxidation, yellow materials become orange or red.
|
[
top ] |
| |
|
Water
Finishing
This process consists of passing
a pipe emitting a jet of high-pressure water over the
surface to be treated. The effect is the negative
of what happens with thermal finishing. While with
flaming the hardest part of the material bursts and
is removed, in water finishing the softest part is removed. But
the result looks the same, the surface is similarly
rough. The colors of the material and the veining
pattern are not affected by water finishing and the
esthetic effects are comparable even to those obtained
by polishing. As water finishing does not induce
oxidation, it is the usual finish employees for making
yellow material non-slip. |
[
top ] |
| |
|
Antique
Finishing
Special machinery that looks like
industrial washing machines is used to obtain an antique
finish. The pieces to be treated are put in the
machine with abrasive elements and the cylinder revolves. In
a short time the impact of the stone with the abrasives
produces an effect similar to aging caused by use and
wear. The impact method is not suitable for large
pieces, for which brushing or acid washing is the method
of choice. |
[
top ] |
| |
|
 |
|
| |
|
Chemical
finishes are applied to stone in order to produce reactions
that transform the material surface, or they are
employed together with other types of treatment in order
to improve their characteristics. These finishes
can also be applied to cut, or even installed, materials. |
[
top ] |
| |
|
Acid
Wash
Acid washing has a corrosive action
on the stone. It can be used to obtain different
effects depending on the material, the chemical, and
finally, the processing time. Finishes can range
from simple superficial cleaning of the material to
a more definite ruggedness, similar to that achieved
by water finishing. Acid washing is sometimes used
to obtain an antique finish in place of the impact method. It
is possible to acid wash already cut pieces or, with
appropriate precautions, already installed ones. Some
chemicals produce other results affecting the aspect
of the stone but not its roughness. There are acids
that remove oily or rust spots on the material others
that instead induce oxidation effects and are employed
to change the material color. |
[
top ] |
| |
|
Epoxy
Treated
This method consists of several steps:
-
One face is honed to create a
smooth surface on which the resin is applied.
-
The slab is dried in a special
oven to allow the resin to penetrate into the material
and set;
-
Resin is poured and spread on
the slab.
-
The slab is put in the oven again
to dry the resin.
-
When the slab comes out from
the oven it is ready for polishing.
This complex process has two main goals:
the improvement of the material's esthetic characteristics
and its mechanical resistance. The high fluidity
of the resin allows it to penetrate the smallest interstices
and to fill defects in the material. Unlike resin
treatment, cement filling, usually applied to travertine,
is employed for purely esthetic reasons. |
[
top ] |
| |
|
Meshed
In addition to resin treatment, in
order to strengthen material it is common to apply a
thin net made of fiberglass or plastic on the back side
of the most defective marble or stone slabs. |
[
top ] |
| |
|
Protective
Treatment
This category includes all those
treatments that are used to protect the material surface
from external elements. Among them are hydro- and
oil-repellent treatments used to seal kitchen countertops,
anti-graffiti treatments to avoid damage caused by vandalism,
and products that give a wet appearance to flamed stone. These
products are often the final protection given to finished
and installed stone. |
[
top ] |
| |
|
