Saturday, July 6, 2013

Guest post: Rachael Sudlow / Lost Wax Casting

Rachael Sudlow is an artist who has participated for several years at the Bizarre Bazaar.  She is a creative metalsmith who also teaches classes at the Lawrence Arts Center.

One of the techniques that Rachael uses is lost wax casting.  She has provided information to share the process and some resources below in a guest post.

The process is also demonstrated in a video here.

Lost wax casting is how most typical commercial jewelry is created (most wedding rings are made this way!).  The piece starts as a carved wax model.  This is finished, smoothed and sized to perfection.  An example of some of my wedding bands can be seen being prepped here.

The waxes are then setup on a stick of wax called a sprue.  The sprue holds the ring in place and when the molten metal is poured, creates a pathway for it to flow into the design.  Many wax pieces can be cast at once. 

After the wax pieces are all mounted on a special rubber base, a steel jar is fitted over the setup.  The top of it is open and a special plaster mix called investment is poured in.  That it is left to dry out for a few hours.  The rubber base is then pulled off, revealing a formed pour spout leading to the waxes, which are now locked in place in the investment. 

The flask is put inside a kiln and heated up over a matter of several hours.  This burns out the wax, revealing a hole in the desired shape. 

The metal of choice (bronze, silver, gold, etc) is heated till it's molten.  At that point, the mold flask is pulled from the hot kiln, put on a vacuum table, and the molten metal is poured into the spout.  After a few seconds of vacuuming, the flask is pulled off, dunked in water and the metal piece is revealed.  The cast rings can be seen here.  LOTS of cleanup must occur after that. 

Those raw rings are then polished up and can be seen here.

Because of casting safety issues (we are dealing with molten metal and burning wax!), I do all my casting at the Lawrence Arts Center in their well outfitted jewelry classroom.  I teach jewelry classes there and am happy to share the process!

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