Although an ancient practice, the lost wax process today may vary from foundry to foundry.  However, the steps which are usually used in casting small bronze sculptures in a modern bronze foundry are quite standardized.

Here at WHC we use a unique vacuum cast machine.  This one-of-a-kind casting machine was originally built specifically for NASA.  We acquired it in 2009.  We call her "Big Red".  She's a bit of a diva and has high standards.  Lucky for us, where she's the happiest is making belt buckles in our standard style fashion.  We start getting too thick, or too thin, or heaven help us, a sphere, and she is just not having it.  She also refuses to work for less than top-shelf metal grain.  So no recycled metal here.
​
There are a few things that set us apart in the world of casting.  First is the fine-tuned precession pours under pressure and vacuum our machine provides.  Other foundries use the older technique of having to create a shell of investment slurry (a plaster of Paris type solution) around their waxes, and then, after the wax is melted out, they use giant vats of molten bronze to pour into the empty shell.  With our machine, we do not have to go through the waiting stages of a shell investment to set up.  That process can take upwards of a week or more to create a thick enough shell around the wax before the molten metal pouring can begin.  Our process uses specialty fit cans or flasks that are built specifically for this machine.  These cans are filled with as many waxes as we can fit at a time, and then our investment is poured around it, filling the can.  We also vacuum the invested cans in their liquid state to help eliminate any air trapped around the wax.  The slurry content of these cans sets up in about an hour and can go directly into the Burnout oven.  The other, more notable difference is that we use high-grade rubber molds to make our waxes.  These molds are traditionally used for low-melting metals, which we use as them for as well.  Spinning wax into them not only makes our production go faster, but also creates a perfect wax for casting.  A perfect wax is one without airbubbles or imperfections. This aids us in the cleanup, as a perfect wax tends to be a perfect cast. 
​

The other difference with our process vs. the standard casting method is that we only melt enough bronze at a time to cast exactly what we need for each can.  By weighing out the wax weight and using a conversion method, we can determine the exact amount of bronze needed for each can.  What really sets us apart is the fact that once the door shuts on the casting chamber vacuum begins, and nitrogen gas is introduced to create a completely inert, pollution-free casting environment, resulting in perfect castings.

After the bronze drops into the can, it can almost immediately be removed and set aside to cool.  There are two methods of breaking out bronze from the investment cans: quenching or air hammering.  We opt for quenching.

The finishing process is quite simple around here; we do a chemical bath of chemical black and polish back to create a lovely natural bronze contrast.