A custom-designed gold pendant begins as an idea and pellets of the precious metal.
Goldsmith James Goss, owner of Goss Family Jewelers in Hermiston, said gold casting is a centuries-old art form. The method he uses to create custom jewelry, such as a pendant featuring elk ivory and diamonds he created for a display piece last week, is lost wax casting.
With an idea for a piece in mind, Goss starts by carving a precise mold for the finished product in wax.
“Every piece is different,” Goss said. “Sometimes I draw it to give me an idea, but, when I start working with the wax, it doesn’t always turn out like it did in the drawing. It’s like sculpting with clay, basically, but I’m doing it with wax and a pen.”
The wax pen allows him to shave off tiny pieces of his design, add wax where necessary and meticulously prepare channels and holes for the jewels.
“I take my hand tools and carve out where the diamonds are going to be,” he said. “Everything is hand-sculpted in the wax.”
Once the carving is complete, he weighs the wax and determines how much gold, sitting in little pellets in a plastic bag, will be needed for his piece.
The wax carving is used to create a mold for the final product. The mold is made from a material called investment compound that surrounds the carved design, and the wax is ultimately melted away to leave the space that will be filled with gold.
To allow a passage for the molten gold to flow into the carved design, Goss melts and attaches a wax cone, known as a sprue, to the original wax carving. He secures the wax carving and sprue inside a metal cylinder, known as a flask. The small end of the sprue cone is attached to the wax carving, and the large end is screwed onto the flask lid, so when the flask is filled with the solidified investment compound and the lid is removed, the wax sprue is visible, which creates the hole in which the gold is poured.
Goss mixes investment powder with water to make the compound.
“Basically, what you want it to look like is a pancake batter,” he said. “Once you start this, you only have so much time because it sets up and gets hard.”
He pours the mixture in the flask, and it surrounds the wax. As the investment compound begins to harden around the wax, he sets the flask aside until it is dry enough to place in a kiln without shattering.
After several hours, Goss removes the flask lid and places it into a kiln with the sprue pointing down so the wax can melt out as the investment mold is baked.
“That’s why they call it lost wax casting — because all the wax actually melts out,” he said.
The kiln, which is on a timer, slowly heats up through several stages to reach 1,250 degrees Fahrenheit overnight, and it holds the mold at that temperature until Goss is ready to pour in the gold.
The following day, Goss prepares a small ceramic bowl, known as a crucible, in which he will melt the gold. As he holds the 2-foot handle for the crucible, Goss heats it with a torch until it is glowing in a bright red hue.
He adds and heats casting flux, a material that keeps the gold from sticking to the crucible. Goss then pours in the gold pellets and melts them with the torch while stirring the gold with a metal rod.
“You have to constantly keep heat on it,” he said. “As soon as you take the torch off (the gold), it’s automatically hardening. It’s a quick process. (The investment mold) will still be in the kiln getting heated, and the gold will be getting melted.”
When the gold is melted into a liquid, Goss removes the flask containing the mold from the kiln with tongs. While continuing to hold the torch to the gold, he quickly pours the molten metal from the crucible into the sprue hole, and it flows into the space left from the wax carving that melted away in the kiln.
The gold hardens as it cools in the mold, changing from a bright red color to a darker gray color, and then Goss uses tongs to place the flask in a bucket of water. When submerged, the hot investment mold disintegrates and causes a burst of steam, leaving the gold in the bottom of the bucket.
Goss places the gold in a “pickling solution” to remove impurities from the heating process and then into a vibrating cleaner to remove any remaining investment mold.
He takes the freshly casted piece of jewelry and cuts off any excess gold that remained in the sprue hole and files it down until the gold is in the same shape as the original wax carving.
Goss proceeds through a series of filing and sanding stages to remove any rough spots until the surface is smooth. He then places any stones into the holes he designed in the wax and tamps the gold around them to hold them in place. If the piece contains elk ivory, he glues it into place. He sands the surface again to remove any marks created while adorning the gold.
Goss uses two stages with separate compounds to create a “high polish” finish. He then uses a vibrating cleaner to remove the polishing compound and then steam cleans and inspects the final product.
From an idea carved in wax, through a mold filled with molten gold and hours of sanding and polishing and placing stones, the custom piece of jewelry is complete.
“This is from start to finish,” Goss said. “This is an art.”
The diamond-accented elk ivory pendant hangs on a chain on display inside Goss Family Jewelers, 230 S.E. Second, Suite 3, Hermiston. Although elk ivory cannot be sold, Goss said he can create jewelry around pieces brought in by customers.