My daughter Shelley and I became well invested in our craft projects last night. We are taking wax carving and lost wax casting workshops at the Craft Guild of Dallas. Investment is the plaster like material that surrounds our wax carvings and forms the molds for casting our work in silver. The wax is melted and burned out of the investment (the wax is lost) then the cavity is filled with silver, Sterling silver actually.
We put sprues on our creations to direct the silver into our designs and then we were doing vacuum degassing of our investment so there would be no bubbles in the molds. It’s kind of cool watching the casting material (investment) boiling out the entrapped air under a bell jar that held the vacuum.
As I wrote, we will soon lose the wax during burnout and then after spin casting we will also lose our entire investment. Both are totally destroyed in the process of lost wax spin casting. However, we will have what was once carved in wax exactly duplicated in silver and that is not lost.
I invested two items last night, a finger ring and a necklace pendant. Shelley got her first ring finished so she invested that. Next Monday night we turn them all into silver when we finish the burnout and then spin melted silver into the 900 degree investment molds.
Yes, it is a fiery hot process as the molds are baked at over 1,100 degrees for ten hours during the burnout and mold hardening process. The molds will then be allowed to slowly cool to 900 degrees where they will be held at that temperature until we are ready to cast.
The silver castings will need more finishing work after they are cast so we are sill a couple of classes away from a final product. Then I will show pictures. Meanwhile we will be carving more wax.
I am building a home workshop for metalworking and silver casting is high on the want list.