Lost Wax Process of Designing
The Lost Wax Casting process was used in designing all the pieces in my line. It is an ancient process and while the technology has advanced, the concept of using wax to create art has been used since Egyptian times.
I often do a drawing of the design on tracing paper and then glue it to my wax sheet. I then trace the design into the surface of the wax using a series of cuts and pin pricks. I cut the shape of the design out with a saw blade and give it depth by building up and cutting away the wax using hand held carving tools and a source of heat. I use a combination of alcohol lamp and wax pen.
Sometimes I won’t bother with a drawing and just go directly to the wax which comes in various forms: sheet, tube, round, square, triangle,etc. The length of time it takes to create a model depends upon the design, how simple or complicated. Sometimes it can take only a few hours while others are worked on over a number of days.
After the wax model is completed, I attach sprues or channels which are also made of wax. I mount it on a sprue base which is a rubber disk with a flat-topped cone shape in the center and is filled with wax. I affix the model to this cone shape and place a flask over all. The flask is then filled with plaster. The plaster sets up in about 11 minutes, just like plaster of paris but this stuff is heat resistant. When the plaster hardens, I remove the base which exposes the sprue openings. I place the mold in a kiln and over a period of hours, heat it up to 1,200F. The channels or sprues allow the wax to melt out of the mold and leave a negative space inside the plaster which is how the silver enters the mold. At this point the original wax is lost, hence the name Lost Wax Casting.
After the mold is heated for eight hours, I remove it from the kiln and place it in my centrifugal casting machine. The arm of the machine holds the mold, crucible and the counter weights. The base of the machine contains a large spring which drives the arm. The silver is placed in a crucible directly in front of the mold. I melt the metal with a torch and when it is molten, I release the spring and the force of the spinning pushes the molten silver into the mold. (Silver melts at 1,645F and gold at 1,900F).
When the machine stops spinning, I remove the mold with tongs, allow it cool for awhile and then drop it into a pail of water. The plaster collapses exposing the unfinished casting. I then have to cut off the sprues which are now either silver or gold (they are reusable) and begin the process of finishing the casting. Silver and gold are finished using the same techniques.
This piece then becomes my master and from there a rubber mold is made. To make more copies, liquid wax is injected into the rubber mold and the whole lost wax casting process starts over again.