The Bronze Casting Process

For More Information on Casting, Enlarging, Reduction, Molding, 3 D Imaging, or Milling of a Sculpture



Step 1

A steel armature is fabricated that will function as a ”skeleton” to hold the weight of the clay  The piece is sculpted using an oil based clay


The piece is worked and reworked until both the artist and client are pleased  The finished life-size sculpture


Thin sheets of metal are used to divide the sculpture in to a predetermined number of sections  A latex rubber is applied to the clay sculpture.  5-6 coats are used to build up a sufficient thickness


The molds are backed with plaster, which will give rigidity and support to the rubber  The plaster pieces are removed and the latex is cut down the center to create a two section mold


A finished set of Molds  The molds are coated with wax to create a copy of the clay original


Wax is poured in, the mold is rotated to evenly coat, and the excess wax is poured out. This will create a hollow replica  A finished wax being removed from the mold


One finished wax piece  The pieces are touched up and wax runners and a wax cup are attached.  The cup and runners will later act as funneling system to enable the bronze to reach the piece


The pieces are coated in a liquid ceramic and allowed to dry.  This will be repeated 7-8 times to build a thick ceramic shell.  The shell becomes another mold  Finishing the first coat


The piece is next coated in sand. This will help dry it quicker and add mass to the ceramic  The ceramic is chipped away from the bottom of the cup gaining access to the wax.  The piece is heated and the wax melts, leaving a hollow ceramic shell


The mold is now hollow and ready for bronze to be poured in  20 lbs. bronze ingots will be melted and poured into the shells


The bronze is melted in a crucible in a furnace to over 2000 degrees  The ceramic shell are also heated, to prevent them from shattering from the shock of the molten bronze


The shells are removed from the oven and place in a sand filled box with the cup facing up  The cup acts as a funnel and the runners carry the bronze to the piece


Once cooled, the ceramic shell is chipped away. Then the cup and runners will be cut off  A finished set of bronze pieces ready to be reassembled


Using heli-arch welders the bronze pieces are welded back together.  The sculpture is ground and polished to create a seamless finish  The sculpture is heated and treated with chemicals that oxidize the bronze changing its color to the desired effect


The finished piece is not only beautiful but strong and durable able to last generations!

The piece used in this demonstration is “Leap Frog” (lifesize) by Scott Streadbeck