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Creating a Bronze - Slide 1 of 26 The process begins
with the artist's original piece sculpted in clay,
wax, wood or other material. First a mold is created of the artist's
original model, a
soft clay is used to cover the model, and then build a "plaster of
paris" cast around the clay. Dams are created so the cast may be
separated after it has hardened.
Creating a Bronze - Slide 2 of 26 As the plaster
cast is opened, the clay covering the model is revealed. Determining
where the plaster cast will come apart and how thick a blanket of clay
to use, takes knowledge and experience.
Creating a Bronze - Slide 3 of 26 Once a mold is created, a wax pattern can be made by pouring hot wax into the mold. In the picture below the artisan is preparing to open the mold and reveal the wax pattern.
Creating a Bronze - Slide 4 of 26 In this picture, you
can see the plaster shell, the rubber mold and the wax pattern. The wax
pattern will move on to the next stage of the process.
Creating a Bronze - Slide 5 of 26 Here the wax pattern has been removed from the mold. From this point, the wax pattern moves to the chasing and sprueing section of the foundry.
Creating a Bronze - Slide 6 of 26 Here you can see the other pieces that have been created in a different mold. These pieces will be assembled after the sculpture has been poured.
Creating a Bronze - Slide 7 of 26 Each part must be chased to have the extraneous wax bits carefully removed and and be prepared for the investment process
Creating a Bronze - Slide 8 of 26 The chased and
sprued wax is ready for the next step called investment.
Creating a Bronze - Slide 9 of 26 The chased and sprued wax piece is dipped into a vat of silica slurry and set to dry. The artisans will build this shell up by mixing the slurry with several grades of sand, from very fine to coarse.
Creating a Bronze - Slide 10 of 26 In this photo the artisan is pouring the finest grade of sand over the still tacky silica coating. This process will be repeated until the finest details are covered with a solid layer of shell.
Creating a Bronze - Slide 11 of 26 After the first layer is completed, the piece goes to a coarser grade of sand that will build up a thicker shell. Here you see the piece with the first shell completed.
Creating a Bronze - Slide 12 of 26 The picture below shows the completed investment with all the layers of sand and ceramic being air dried. The investment process takes time to do properly. The more carefully this step is completed, the better the result in the pour.
Creating a Bronze - Slide 13 of 26 Once the investment is dry it is bound and grouped with a number of other invested pieces. They are stacked in the furnace and heated to 1600°F. The wax melts and runs out at the bottom of the investment. What is left behind is an empty shell with the details of the sculpture.
Creating a Bronze - Slide 14 of 26 The shells are removed from the oven and placed in a tub full of sand. The crucible is removed from the furnace and moved to the location of the shells. The bronze is poured into the shells.
Creating a Bronze - Slide 15 of 26 The pour must be carefully handled. The temperature of the molten bronze is critical to a successful pour. The artisan must control the speed of the pour in order to maintain a high quality bronze without defects.
Creating a Bronze - Slide 16 of 26 After the bronze is poured and allowed to cool, the investment shell can be broken away. This is hard dusty work for the artisan. The ceramic shell is very brittle but also very hard.
Creating a Bronze - Slide 17 of 26 Here is the piece after most of the investment has been broken away. At this point the work moves to another area where artisans will carefully blast off the remaining investment and prepare the bronze for welding and chasing.
Creating a Bronze - Slide 18 of 26 Now the work is ready for assembly. The bronze is polished and cleaned up so that the parts can be welded to the main body.
Creating a Bronze - Slide 19 of 26 Assembling the parts, welding and grinding the piece is the part where the artisan's knowledge and experience is crucial. The artisan works closely with the artist to make certain that the piece is correct.
Creating a Bronze - Slide 20 of 26 The additional parts of the sculpture are welded to the main body helping to restore the detail of the original piece. A high level of skill and patience is required in order to assure quality in the assembly.
Creating a Bronze - Slide 21 of 26 Assembly complete, the final step is patina. Patina involves putting a finish on the bronze.
Creating a Bronze - Slide 22 of 26 Here, the patina is being applied. The artisan works with a brush and a small torch to apply the patina and oxidize the bronze.
Creating a Bronze - Slide 23 of 26 The patina process involves painting on a layer of chemicals and then applying heat. Using different minerals creates different colored patinas.
Creating a Bronze - Slide 24 of 26 Another picture of our casting during patination. Using different chemicals in different combinations and strengths results in the creation of different colored patinas.
Creating a Bronze - Slide 25 of 26 As the artisan works on the patina, the sculpture's details come to life. A great deal of knowledge and experience are required in order to produce the best patinas.
Creating a Bronze - Slide 26 of 26 The completed work on a walnut base with the name plaque installed.
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The information above is provided courtesy of Kalispell Art Casting Inc. Kalispell Art Casting is a flourishing bronze foundry in the Flathead Valley of Montana. They cast sculptures for sculptors and corporations from across the U.S. and Canada. Find out more about Kalispell here: www.KalispellArtCasting.com Please note: The artwork in the demonstration above is not that of Donna Wilson. ![]() |

