Lets talk about Lost Wax Casting (Part 1)

Lost wax casting is the process of creating an original work out of wax, which is then casted into metal (bronze, silver, gold...). I had no idea what I was getting myself into the first time I signed up for my first lost wax casting class, but I fell in love ALMOST immediately. My first wax ring was pretty much a failure and it never even made it into silver. My second wax ring was a pretty sizable chunk of wax, which became a pretty nice chunk of silver, and may resemble a pot leaf (totally by mistake, I swear!), but I still love it anyway.

So you may still be asking....Ummm.... I'm still confused about what exactly is lost wax casting? Lets get started shall we? The fist step is to create your original work in wax.

For this particular design I used sheet wax, which is a very malleable type of wax that can be cut using an exacto knife and molded with your fingers. Sheet wax tends to be brittle when cold, so it helps to heat up the wax either with the warmth of your hands or, if your hands are always frigid no matter the weather (like mine), you can heat the wax under a light bulb. Once I cut out all of my leaf patterns (seen on the left) I mold them into the desired form and then heat up a dental tool with a little alcohol lamp in order to melt the individual pieces together.

Alcohol Lamp



On the right, is a picture of the alcohol lamp I use to heat up my various dental tools in order to melt the various wax components together or also to drip on additional wax. The lamp is filled with denatured alcohol, which surprise, surprise is very flammable if you manage to knock over your lamp and spill the alcohol all over your table while your lamp is lit! Always fun!



Orchid Sprued

After you put out any inadvertent fires that you may have started with your alcohol lamp it is time to "sprue" your wax piece. The point of sprues is to create channels for the molten metal to flow through during the casting process. During casting metal prefers to flow forward in a straight line. The metal does not like it when it is constrained to a narrow channel that then opens up to a thin wide area (like you see in the top right leaf) and the molten metal gets really angry when it is asked to turn right angles during the casting process! When sprueing a wax piece it is important to keep in mind all of those characteristics of molten metal. In the picture to the left, I chose to attach one big sprue in the middle of the flower, which will help to direct molten metal to the two top petals. The two smaller sprues on the right and left will fill the two smaller outside petals and then one more small sprue that will fill the larger bottom petal. I also attached a small wax jump ring to the back of the flower, because I am intending for this piece to be a pendent.

Sprue BaseThe last step before preparing the wax for the investing process and then casting is to attach the sprues to a rubber sprue base. Please excuse my change of wax flower in the picture (I'm just making sure no one has fallen asleep yet!). The top of the sprue base is covered in sticky wax (yet another type of wax that is...wait for it...sticky and also melted under lower temperatures - love when they keep it simple!). Once you have secured your wax to the sprue base, the next step is to attach a metal flask on top of the base in preparation for investing.

Look for that exciting description in my next post!!