We use the Lost Wax process a lot here at Walker Goldsmiths. I really enjoy knowing that it’s an ancient procedure that, of course, has been upgraded to meet the modern tools, but all the same, it’s still an ancient practice.
Metal casting has been archaeologically found to have begun in India around 3500 BC with the earliest known lost wax casting. Ancient craftspeople used beeswax to create the image and the metals freely used were Copper, Bronze, Silver and Gold. All over Asia, Egypt, Europe, the Bronze Age Mediterranean areas, Africa and Latin America there are antiquities to be found to show the lost wax process was used to create what the people wanted.
When making a ring using the lost wax process I first have to carve a wax to the exact specifications needed, like size, width and height. If there’s stones to be in the ring the seats for the stones to sit in can be cut into the wax or just the right space for crowns to be welded in after the ring is cast in metal. If the ring is a custom order, this is the time for the final OK from the customer. Adjustments are so much easier in the wax than in the metal! Owen says, “10 minutes in the wax or 1 hour in the metal” to remind me to make those changes in the wax before it gets to him to cast and finish.
The wax is then put on a little post support called a Sprue and set in a base with a tube surround. We call it spruing up the wax. At this point a slurry of investment like a very smooth plaster is poured in and around the wax ring where it’s left to dry to a very hard state.
This is where the “Lost Wax” legend comes in…sounds very mysterious, but it’s just an accurate description of what happens. The wax in the flask is then brought up to the melting point of the wax by either steaming it up to temperature or baking in a kiln and the wax is totally lost at this point and all that’s left is the imprint of the wax.
Then on to Burn Out where the totally empty flask with the imprint of the wax inside is brought up to the temperature where the wax is completely consumed. The goal here is to get the metal into the shape left by the wax. Owen uses Centrifugal Casting that shoots the molten metal into the hole where the wax was. The plaster investment that the metal was centrifugally cast into is boiled off the casting by immersing the extremely hot flask into cold water and the investment comes apart and away from the metal ring and boils off. Lots of steam and splashing about here at this point!! Then there’s Finishing, meaning cutting/sawing the ring off the sprue, checking the size to be accurate since there’s always some shrinking in the process, sanding, polishing, final touch ups, possibly soldering on the crowns and setting the stones. Then another polishing, cleaning and photographing at Walker Goldsmiths! Voila! A Ring!