Artistic talent from the University of St. Francis was captured recently during a 3-credit summer course, in the medium of bronze. The bronze casting process was taught by Michael Warrick, a visiting artist, teacher, and lecturer. He is well known for his work with non-ferrous metals, like bronze, and currently has pieces on display and for sale in the Goldfish Gallery at USF.
When the sculpture class began the students agreed that it was best to have some idea of what they wanted to create before they started–no matter how vague an image it might be. As the students worked on their petroleum-based wax sculpting, ideas came, not knowing from where. The shaping and sculpting was done mostly with dental-type tools. “The wax should be soft enough to shape and yet hard enough to stay put and hold detail,” explained Communication Art and Graphic Design major Alex Cornwell. “The key to sculpting is observing from every angle,” said instructor Warrick. For a few of the students their sculptures were small and required special handling.
After the wax sculpture was complete, it was attached to wax funnels to provide an entrance for the molten metal, bronze. The sculpture was attached to a funnel by “welding” wax sticks (sprues) to both the sculpture and the funnel. The tip of a metal tool was heated up (over a torch). Then a wax stick was joined to the wax funnel by using the hot metal to melt the pieces together. Thicker sprues were joined to the sculpture where the bronze entered (the bottom), while thinner sprues (vents) were joined at the top edges of the sculpture and reached to the top plane of the funnel. “Sprue placement is very important, since the air that is in the mold before the bronze is poured must escape, otherwise it forms air pockets which the bronze cannot fill,” explained Cornwell. Also, since using this method created sculptures of solid bronze.
The next step was to dip the piece into a “slurry” solution, a liquid mineral compound. The project was allowed to dry, dipped into slurry then coated with extremely fine sand to start, and, progressively dipping into coarser sand. Taking about 2 hours to dry between coats. The sand added detail and strength to the piece, while the slurry helped to bind and harden.
With a mold made around the wax, the students then submitted their work to the inferno, heating it to 1500 degrees Fahrenheit. “Burn out” occurred, and the wax was lost. If the mold is broken or damaged somehow, the molten bronze will leak through and the cast will not fill properly.
After hours and hours of detailed work the perfected molds were finally ready for their bronze casting. From 9am to 2pm on Saturday, June 22 thirteen students from the University of St. Francis fired their works of art.
Each artist took their turn at removing their mold from the oven-a big cylinder-lifted by another student via cable and pulley. The mold was then set into a big metal pot filled with sand (which safely supports the mold).
The melted bronze, composed of tin and copper, was removed from the furnace and poured into the artist’s piece.
The hot mold is carefully removed, kept in an upright position, and allowed to cool. The cooling process can take up to a day depending on the thickness of metal in a piece.
Once the bronze had completely cooled, the mold was broken. The raw piece of art was finished by cutting away the sprues with a hacksaw or electric grinder. The final cleaning and shaping of the sculpture is done with a Dremel tool and/or a sandblaster as well as hand tools. “Most of it cracks away fairly easily, but the stuff that gets stuck in the cracks and crevices is very difficult to remove,” mentioned the student. A final polish and clear or colored patina (surface sheen that develops with age and handling) is added to the sculpture as desired.
Completed in partnership with the wax, fire and bronze, there were triumphs, and, yes, there were failures, which were repaired.
The University of St. Francis’ artistic works, using techniques taught by Michael Warrick, were unique. Each was developed with its own personality. And, many of the sculptured creations had a special or personal meaning.