Thursday, February 12, 2015

2.12.15 By the light of the silvery moon

Wax for casting - finished on Saturday
After 8 hours of sawing, carving, filing, heating, filing and carving some more on Saturday, I had this little wax moon pendant.  The last thing we did to the wax before calling it a day was to prepare it for casting by attaching it to a sprue (a small tube that allows the molten metal to flow into the mold) and putting it in a heat-proof cylinder called a casting flask.  This allows the flask to be connected to a casting crucible so the liquified metal can be poured in.

While the students were gone, Courtney and fellow Creative Side Jewelry Academy instructor and jeweler, Wynn Bradford, were busy getting ready for the next day.  They put the casting flasks in a kiln, vaporizing the wax - hence the term "lost wax" - leaving behind a void in the shape of my pendant in a plaster of Paris type medium - called investment. The flasks were left to cool overnight, and ready for us on Sunday morning. 
Argentium silver casting grain

I started with 16 grams of  argentium silver,  just enough to cover the bottom of a small Dixie cup.  Now I was ready to melt, pour and turn these little silver pebbles into a piece of jewelry.  

With my casting form ready to go, and my silver casting grain measured out, it was time to turn up the torch and cast.  The casting flask is aligned with the crucible where the metal is melted and poured into the mold, and then spun in a centrifuge to ensure even distribution and no bubbles or flaws in the finished piece. 

Heating casting grain to molten.
Photo credit: Creative Side
After allowing the flask to cool, and removing the plaster I had my cast piece, which to my great surprise looked like a lot like jewelry - even in it's unfinished form.
After casting
The next steps were straightforward - but time consuming - saw off the excess metal, file down the rough spots and polish the silver to a nice, high shine.  All the tools I needed were at my bench or elsewhere in the studio, so I got to work.

For the next several hours I worked to refine the surface of the pendant.  First with a coarse metal file, then with finer files.  After the files came sandpaper, moving from a coarse grit - around 300 - to one so fine you almost couldn't feel anything on the surface. It was amazing to watch the silver start to shine and begin to look like a real piece of fine jewelry.
Preliminary polish

With the hand finishing work done, it was time to move to the machines.  Small and large - hand held and bench mounted - there were tools with spinning wheels that removed burrs, scratches and marks, and others that added texture and polish. The last step was to solder on a jump ring so that the pendant can be worn.

The final result - 6 oz of shiny silver knowledge and beauty, and a fun, fun weekend.

Until next time.
Ta-Da! Look what I made!

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