ART IN THE MAKING
The Creation Of A Ronadro Bronze by use of the traditional lost wax casting process
ln the Ronadro studio the master sculptor puts the finishing touches on his latest work
of fine art. With artistic lines and accurate interpretation, this newest sculpture, honoring the
medical profession is now ready for an amazing and commplicated series of events which will
culminate in a richly patined, beautifully conceived and executed work of fine art.
This fragile work of art is carefully
transported to the foundry. The sculpture is to be produced by
Michael Hall's Studio Foundry, in Driftwood, Texas, only seven
miles from the Ronadro studio. Ronadro and Michael Hall have worked closely together since the late 1980's, Hall often
acting as a technical advisor, regarding the intricacies of the molding and bronze casting
process, thus allowing Wicks to achieve remarkable compositions in balance and dynamics,
unattainable by most artists.
THE MOLD MAKING
Ronadro's original sculpture may initially be created in a wide variety of materials, includlng
plasticine, (an oil based clay) terra cotta or stoneware, (water based clay) plaster, wood or wax.
These diferent mediums allow Ronadro to create the unique texture varieties so recognizable
throughout his collections of fine art.
The lost wax process, also referred to as cire pardue, requires first, the careful engineering of a
quality mold, made from Ronadro's original sculpture. This flexible rubber mold is used to create a
hollow wax copy of the original, which is eventually "lost", at last to be replaced with molten
bronze. Rubber molds, most commonly made from different types of cold molding compounds,
activated by catalyzers, are brushed or poured onto the surface of the original. The mold is
removed, in several sections, if the original art is larger than about hand size. These rubber
mold sections are supported by a plaster caseing, called the "mother mold", allowing the
flexible rubber mold to be held rigid enough, and in perfect form for the wax pouring stage of the
process. The complex network of rubber sections are keyed, all components bound together
within the mother mold, and sealed for pouring. This rubber mold is used each time the artist
desires to create another copy of the sculpture. The series, or reproductions of an original work
of art is termed an edition.
THE WAX CASTING
The new mold is now ready for creating a hollow, wax positive, capturing in thumbprint detail,
the exact work originally sculpted. This, and every wax, will ultimately be lost in the "burn-out"
part of the process. Studio Foundry makes and uses a specially formulated pattern casting wax,
which is heated and carefully poured into the mold. The mold is gently rotated to insure an even
coating, always being mindful of surface bubble elimination. The wax may also be brushed into
the open mold for the first coat, after which the mold sections are then closed and bound for
additional wax pourings. Several wax pours at specific temperatures are necessary to develop
the required wall thickness of the wax sculpture, approximately one eighth inch, which must be
relatively uniform to insure a good metal pour. lf the wax is not consistent, thinner areas will
inhibit the smooth flow of the molten bronze, resulting in unseen weaknesses in the final cast,
or even an unusable casting due to voids.
The wax is then given enough time, in the undisturbed mold, to cool, after which it can be
carefully removed from the rubber mold. Chasing, a term which means to clean and re-sculpt, is
done twice, once in the wax and again when the sculpture is in bronze. Wax chasing is done
with heated metal spatulas, knives and assorted wax sculpting tools, allowing the wax chaser to
remove any flashings, or irregular fins of excess material, which may have seeped into tiny gaps
between seams. Spru and vent joins are areas on the sculpture, where the molten wax has been
channelled to fill the sculpture, and where vents have been designed in the mold to allow
trapped air to escape, as the wax is being poured. These areas must also be chased off the
sculpture, along with all other undesired surface irregularities, such as tiny bubbles which must
be filled and re-textured. The wax pouring and chasing specialists at Studio Foundry are all
artists, highly skilled in resurfacing the sculpture, to the exact requirements of Ronadro, often
referring to the original art piece, to be certain of the utmost detail. Finally, the master himself is
often called in to give his approval, and the process continues.
When the wax copy of the original sculpture meets the exacting requirements of the artist and
foundry, a wax sprue system is designed, with a pouring cup, gates and vents, all attached to the
perfect wax. Gates are systematicly positioned along the wax to channel molten bronze into the
casting mold, and vents are engineered to releave air pressure inside the mold, to insure a
smooth flow of metal into every recess, as the sculpture becomes bronze.
creating the casting mold
During the investment process, ceramic shell is built up around the gated and vented wax
sculpture, leaving the pouring cup and vents open, at the top, until the whole assembly is
sufficiently thick enough to contain the weight of the molten bronze. The ceramic shell
investment material, applied by repeated dlpping, begins with a colloidal silica slurry. When wet
with this slurry, dried silica is stuccoed over the entire surface, by means of a rainfall or fluidized
sanding system. Depending on the size and weight of the whole wax assembly, numerous coats
are applied, (usually about eight), in alternating layers of slurry and stucco. The final application
may be reinforced with stainless steel mesh in areas where additional strength is determined
Now the casting mold is complete and requires removal of the wax within, to make way for the
sculpture to be poured in metal. The entire casting assembly, (called a tree), is then flash
fired as it is placed in the burnout kiln, which has been pre-heated to 1800 degrees fahrenheit.
This high temperature serves both to fuse the ceramic shell and to burn-out the wax entirely,
including the volitilization of any carbon remaining from burned wax. Thusly, we now have a
perfectly clean and very strong, cooling ceramic shell casting mold.
bronze & sculpture unite
The wax burnout leaves a hollow mold, completely devoid of wax and ready to accept the molten
bronze. After close examination for any cracks, and patching if necessary, the ceramic shell
mold is returned to the kiln and brought up to approximately 1400 degrees fahrenheit. At Studio
Foundry, this is a time of reverence and concentration. The work of art has been through
numerous, complicated and time consuming steps to reach this one, critical moment in time.
After the wax burnout and before the bronze pouring, the sculpture no longer exists as an
object, and is defined only by its absence in the casting mold.
While the casting molds are being heated in the kiln, the forced air, gas fired furnace is lit. A
silicon carbide graphite crucible, inside the furnace is charged with bronze ingots. The
composition of bronze used at Studio Foundry is 95% copper, 4% silicon and 1% manganese. lt
is called Everdure Silicon Bronze. ln order to know what quantity of metal is required for this
pouring, a wax weight to metal weight formula is used. The ratio for bronze is approximately ten
pounds for every one pound of wax.
As the bronze ingots in the furnace begin to melt, more ingots are added, charging the crucible
until the desired amount is achieved. Fluxing agents which enhance the pour and trap inpurities
are added toward the end of the melt. The metal is then watched closely as it reaches its
appropriate temperature for pouring, which for bronze is between 1940 degrees and 2200
degrees fahrenheit. The desired pouring temperature is estimated for each mold, based on
various characteristics unique to each sculpture to be poured. When the bronze reaches the
required temperature, the ceramic shells are removed from the hot kiln, and carefully placed on a
bed of sand, stabilized with the pouring cups straight up. The crucible is removed from the
furnace with lift out tongs. The glowing crucible, charged with molten bronze, is placed in a
pouring shank. Any slag or impurities that have floated to the metal's surface are then removed
with a skimmer. A two person team lifts the shank, containing the full crucible and carries it to
the awaiting molds. The pour yard becomes quiet as the crucible is tilted toward the open cup,
and a steady stream of irredescent-gold liquid flows from crucible to mold. Once again, as with
something akin to magic, the sculpture exists as a solid object.
After the pour is complete the molds are allowed to cool. The cooled casting, encased in its
ceramic shell investment, is then devested. Much of this work is done with air tools, switching
to hand chisels as the sculpture's more delicate areas are revealed.
The spruing system with gates and vents, once in wax is now in bronze, must be completely
removed. The surface of the sculpture is chased and retextured, to match the original. Many
works are cast in sections and must be welded back together. When the metal chasing is
complete, with utmost attention paid to every detail with regard to the design and surface quality
of the original, a final sandblasting is performed, removing all oils and contaminates, preparing
the bronze surface areas uniformly for patination.
Patination is the process of applying a patina. Metal coloring, (patining), is not an exact science,
but depends on the technical skill and artistic judgement of the patinuer, working closely with the
sculptor. Patinas are used to create life-likeness in sculpture, and are used symbolicly, in both
abstract and representational contexts, and more generally, to unify and enhance the aesthetics
of a work of art. Although patinas may be thought of as a secondary characteristic of
sculpture, often applied in a process that is distinct from that of creating the art work, in many
cases, it is the key factor in the visual coherence and artistic significance of a piece. Therefore,
a patina is of prime importance.
The long term relationship between sculptor, Ronadro, and the patina specialists at Studio
Foundry contributes greatly to achieve the distinct quality, represented in the often multi-colored,
bronze sculpture created for the Ronadro Collection. Both hot and cold patina applications are
used. Bronze reacts with certain acids and other chemicals, by oxidizing in different colors. For
example, cupric nitrate applied to a hot bronze will oxidize with the metal changing its color to
green. Studio Foundry, well known for its innovative patinas, has developed a broad pallet of
colors exclusively for the Ronadro Collection, some of these effects can only be found in this
collection. The patination process also enhances the ability of the sculpture to sustain the
effects of time and the elements.