Mark Abildgaard
Kiln cast glass sculpture


 Uroboros Casting Residency 2013

Please click on pictures to see enlargements

In March of 2013 I drove from my studio in Northern California to the Uroboros Glass Factory in Portland Oregon.  I had packed my truck with several large plaster silica molds which were ready to be loaded into a kiln and filled with glass.  I had arranged this trip as an artist’s residency with the Uroboros Glass Company in order to take advantage of using a very large kiln which would allow me to increase the scale of my work.  I also would be using their “System 96” casting glass for all of my pieces involved in this project. I thought that I would share the images of this unique experience so that anyone interested in my work would be able to see what happens during the process of creating a glass sculpture.  The finished work is ultimately what justifies the time spent in realizing the vision for a sculpture.  I am still amazed when the plaster mold is removed and I am confronted by a luminous glass casting that is the result of such a long and demanding process.

   Over the past 28 years I have been kiln casting glass in my own studio using the same basic technique.  I sculpt all of my images in solid clay.  After the images are done a plaster and silica mold is made and the clay removed. The resulting “open face” molds can be loaded with glass and fired in an electric kiln to produce solid glass castings.  This simple method has allowed me to create a wide range of glass sculptures over the years.  Recently I began experimenting with a lost wax casting process.  By pressing objects into wet clay and then pouring hot wax into the resulting space I found that I could make solid wax forms much like the method used when casting hot glass into a damp sand mold.  In fact this was exactly how I had produced my first body of cast glass sculpture during a five month residency at the Creative Glass Center of America in Millville New Jersey in 1985.  Looking at one of my early sand cast Totems which was recently on display as part of the “Playing with Fire” exhibition at the Oakland Museum I was inspired to investigate the possibilities for using a lost wax technique to make kiln cast sculpture.  I had already been casting hollow vessel forms using wax so I knew that it was possible to use the wet clay as a mold for wax.  It took me four months to prepare the molds for the Uroboros project.  I began by making a series of hollow clay forms on the potter’s wheel. I then sculpted these forms into an assortment of animal, human and imaginary creature’s heads.  All of these heads were bisque fired so that they could be used for pressing images into wet clay.  I collected driftwood, rocks, old lumbar and anything that looked like it would make an interesting texture.  I built the molds for wax by pressing multiple layers of images into a solid bed of clay.  The largest mold for the wax took around four hundred pounds of clay and was over six feet long.  The wax forms that came out after pouring these molds were covered with archetypal images of animals and human images emerging from a background of organic textures.  The detail was beyond what I could have produced by sculpting in clay directly.  I was able to follow through with the steps involved in making the plaster and silica molds from these large waxes.  In making these molds I used several layers of plaster and silica along with a stronger mix that included fiberglass and pearlite on the outside. The wax had to be removed from the molds by placing them inside a large water tank and running several wall paper steamers underneath to melt the wax.  It took a lot of creative engineering to solve all of the problems along the way but the end result was that I finished the molds for a six foot tall totem as well as a five foot tall totem and a four foot long boat shape. 

   I drove the molds to Portland packed in large cardboard boxes that I made.  I also brought along a hoist so that I could lift the molds into the kiln as well as remove them after the firing.  The people at Uroboros Glass Company were great to work with and I was able to get all of the molds into the kiln and filled with glass in two days.  Each casting needed around 100 pounds of glass so that the entire kiln load took over 350 pounds. I placed each billet (glass slab) in all of the molds by hand in order to achieve the right color effect.  By layering different colors along with clear glass I hoped to get castings that would be able to appear luminous even at the thickest point.  With the assistance of the Uroboros experts we decided on using a kiln schedule that would take 21 days to complete.  This would allow the castings to cool slowly and prevent any stress in the glass that could cause cracks.  After the kiln was started I returned to California to let the firing take its course.  I returned in April to unload the kiln.  Everything looked good as there were no cracks in the molds or glass leaking out.   I decided to leave the castings in the molds for the return trip to protect the surface details from damage.  Using the hoist to lift the castings still encased in their plaster coverings I re-packed them in the original boxes and made the 600 mile return trip to my studio in Northern California.

   After soaking the entire plaster covered casting overnight I began to remove the layers of the mold to reveal the glass sculpture.  I was relieved to see that all of the images that I had created were intact and that the glass colors were better than I could have hoped for.  Several months of work still lay ahead as I still needed to cast bases for each Totem and figures that would fit into the boat form.  All of these sculptures were completed by the end of August 2013. I hope that people who see my work will experience the same sense of excitement, mystery and discovery that I do when I create my sculptures.