There is so much to love about lost wax casting! Since a great deal of jewelry is cast, I thought it would be fun to share the process with you. Lost wax casting starts with a wax model and ends with a finished piece of jewelry. This process is probably the closest thing to “instant gratification” that you can get in jewelry- but there is still plenty of room for error. In Part I of this article, I will share the art of wax carving as I work on producing a new series of rings. Part II will cover investing and casting, while Part III will show the process of finishing up a cast ring so it is ready to wear and sell.
The best part about wax carving is the speed at which you can work, it is soft enough to take off lots of material quickly, yet a skilled carver can still achieve amazing detail. The only downside of wax carving is that it can crack fairly easily when you start to get a thin model. Since a bulky wax model= a REALLY heavy ring, a model with less volume is desirable. For example, a ring that weighs 5 grams in wax will weigh 54 g in sterling silver and 77.5 g in 18K gold! That would cost a fortune and be uncomfortable to wear.
After cutting off a piece ring wax stock and sizing it, my first step is to cut away any material that I know I wont need. The idea here is to get rid of the extra wax as quickly as possible. By sawing off large areas, I save myself time in the subsequent steps.
Scribing a pattern
To give myself an idea of where to carve, I use dividers to mark the wax. In most rings, I will mark the center and edges of all sides, in addition to the edges of my design. Depending on how precise of a carving, this process also requires calipers and some patience. However, this series of rings is really organic and requires no symmetrical carving. I just eyeballed most of my lines.
Roughing out the design
This is the fun part for me. With a coarse file, I begin taking the wax from the boxy slab-shape to my own design. I cut away corners and begin to round out edges. This step is where the ring begins to transform from a chunk of wax into handmade, designer jewelry. It also creates lots of little shavings that look like blue snow. These little snowflakes often end up in my hair- that’s how you can tell I am really absorbed in my work!
When the wax model starts to look more like the intended design, I switch to a smaller file and continue to refine the carving. Each step in the process is conducted to enhance the shape and remove the marks from the previous step. Depending on the demands of each individual model, I may break out my carving tools to help me achieve the design aesthetic I am looking for.Sanding
Once the model is really close to my design, I switch to micro-finishing paper to sand away any remaining file marks. I start with 400 grit paper followed by 600 grit and finish with 1200 grit. Throughout the course of all this sanding, all unwanted marks are removed and the model takes on a polished, slightly shiny finish. It feels very smooth to the touch. I have to be careful not to put too much pressure on the model while sanding- this step is where I tend to crack the wax if I am not careful. Placing the ring on my finger helps support the wax as I work.Adding Texture
At this point, my model is almost finished. All surfaces have been refined and finished how I want them. The last step for this particular design is adding texture. In this case, I use a ball bur in a Foredom Flexshaft to cut away a little bit a wax and create a texture that reminds me of old, worn away concrete. Although the ball bur is capable of taking off a large amount of material, I work slowly with a light touch to get the texture just right.
For this design, I go back in with a bit of sand paper to soften the edges of the texture ever so slightly.
To really bring the shine up on the model, I gently hand buff it with a piece of nylon stocking. I want the model to be finished to the highest quality because it is much quicker to clean up a wax model than it is to clean up a metal ring. Now I am ready to move on to the next stage: investing and casting.
Be sure to check out Parts II and III over the next few weeks to see how the wax model is cast and finished!