Saturday, February 19, 2011

Guest Post - The Lost Art of Lost Wax Casting

The Lost Art of Lost Wax Casting
by Leon Harris

These days, most jewelry is made by machines that pour and press metal into perfectly molded shapes
and sizes that retailers can sell for less (thanks, mass production). And while some consumers have
no problem with wearing the same ring or brooch that hundreds or thousands of other women are
sporting, there are still a few out there who prefer the old-school method of jewelry-making. Lost wax
casting is not necessarily easy, and it does require some equipment and know-how to pull off. But with
just a few simple steps you can have the unique jewelry you desire. And the best part is that you can do
it all in your own home. Here’s how.




1. The model. You’ll want to start by creating a wax model of the piece you intend to create.
Whether you’re forging a simple, chunky ring or a masterpiece of delicate web-work for a
pendant, you’re going to need the right type of wax. It comes in a variety of densities, so you
should probably try some soft and some stiff to find the one that works best for your particular
style, although likely you will use different levels of firmness for your various projects.


2. The sprue. Once the model has been perfected (and you should perfect it since if all goes well,
your final product will look exactly like the model), you need to prepare for the molding process.
This is done by setting your piece on a pedestal, more or less. You’ll attach a thin pole of wax to
the piece (choose a location that won’t interfere with any pattern you have on your work). This
is called the sprue. The other end attaches to a base, virtually suspending your model in midair.


3. The mold. Your base will attach securely to a small chamber (like a cup) that surrounds the
model, leaving only the top open. Now it’s time to mix the mold. The molding material is up to
you, but most people prefer a plaster mold. It is not only relatively cheap and easy to make, the
mix is readily available at craft stores and online. Plus, it hardens quickly and is heat resistant,
which will become important in a moment. For now, simply mix and pour.


4. The metal. When your mold has set, you’ll need a way to get the model out and the metal in.
So the next step involves drilling or digging a channel down to the model. As soon as you see
wax, you can put the plaster mold into an oven (or kiln) with the channel facing down. The wax
will melt and drip out, leaving an empty chamber in perfect negative of your model. When this
is done, you are ready to pour the metal. You can either melt your scrap in a forge or with a
blowtorch. Centrifugal casting is the most common (and least expensive) method of pouring
the molten metal and it involves a makeshift centrifuge comprised of a drum that holds a swing-
arm with a housing assembly on the end. You’ll secure your mold in the housing, attach the
container with the molten metal so that a hole links up to the empty channel in the mold, and
then spin the arm so that the centrifugal motion forces the metal into the mold.


5. Final touches. Once the metal has been “poured”, you’ll immediately cool the mold to set
the metal inside. Then it’s just a matter of cracking the mold to get your finished piece. Of
course, you’ll have to remove the molded metal sprue and do some grinding and polishing to
get it gleaming, but you’ve just created your own jewelry the same way other artisans have for
thousands of years. And it’s one-of-a-kind.

Leon Harris writes for Pennsylvania Precision Cast Parts, a leading medal casting manufacturer
specializing in investment castings. At PPCP you are sure to find the highest quality products at a rapid
turnaround.

1 comment:

Symbol Jewelry said...

Awesome post! You're right to say that no one really makes jewelry using this method anymore. So it's nice to read about it and see pictures too!

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