There are a few ways we approach making jewelry here at Two Birds. Todays post is about Lost Wax Casting and preparing a wax model to be cast.
1. Pick the modeling wax based on approach and desired outcome
Modeling wax comes in a variety of sizes, shapes, strengths, melting points. The picture above is a purple wax brick that I can cut to size depending on the piece. I like the purple because its pretty versatile and easy to work with. The green tube can be cut down to make rings. Green is used for creating pieces with fine detail, and tends to be brittle.
A few of the tools I use with wax (from right to left) are wax saw, which has a spiral blade, wax files, wax ring sizer, mandrel, and fine-tipped wax carving tools. Clean working surfaces are important too. A casting will only be as good as its wax, so if the wax is contaminated, it can mean flaws in the final product.
Wax pens heat up, and have a variety of tips to accomplish certain effects by melting and manipulating wax.
Detail and Finishing
Hand tools and various bits are used to shape wax and pre-form voids in wax where stones will be set. Several grades of fine sand paper to smooth the wax, and nylons to get a high polish. Rather than an alcohol lamp, I use a little tea light to accomplish a super high polish and consistent surface. (The second image of the blue wax bird was taken before the final finishing stage).
Here’s a little Opal Pendant that will be cast into 14K Yellow Gold soon.
Once we have a good collection of finished waxes, we do send our models out to be cast. We don’t have the space or ventilation that would allow us to safely perform this part of the process in house. We use 2 different casters, one in NY, and one here in NM.
The wax models we make are sprued by the caster (which is adding 1 or several tubes to the model. These tubes will create voids or paths in the mold that the molten metal will be poured into.)
Once the wax model is sprued, it is carefully covered in what is essentially a plaster (called investment), cured in a kiln, and the original wax model is lost (it burns off, being lost, hence, Lost Wax Casting). The cured mold is ready for the molten metal.
*I have skipped over the details of the casting process right now, its really not that simple! When we have our casting up and running, I’ll post a more detailed blog.
Our castings still need a bit of finish work when they are returned. Castings are buffed and polished, marked with a purity stamp to denote whether it is Sterling (.925), Fine Silver (.999), 14K or 18K Gold, and our makers mark. Stones are set, and bales and chains are added. * I’ve over simplified the finishing process as well, but will cover that in the next post about fabricating…
Hope you’ve enjoyed reading a little about wax modeling and one approach to the Two Birds jewelry design.
Next up is direct metal fabricating!