I got a centrifuge caster a while back and have cobbled together the parts for the vacuum table needed to invest (make a mold) for lost wax casting. It took several months but the last thing I needed to complete my casting set up was to drill the table for the fitting that draws air out of the bell. I did that Thursday night, and Friday my new torch regulator arrived so I built a table for the caster, soldered with my new torch, invested and burned out a flower that Ali selected and taught her how to lost wax cast.
It was a good jewelry day. Pictures:
The vacuum table setup; The back box is a vacuum pump. The table has a fitting that is connected to the pump to draw air out of the bell (plastic dome). The reason for that is in lost wax casting the mold is a plaster like material called investment, which has to be place in a vacuum twice with in 9 minutes to remove any air in the mixture.
Once the investment has "set-up" (about 15 minutes) the wax is "lost". I use an improvised steam table to removed most of the wax.
The flask (mold) just after the wax has been melted out.
Since there is a lot of moisture in the mold, I do the "burnout" slowly at first. The mold is placed in the kiln and the temperature stepped up to 400 over an hour and a half. At that time all the moisture has evaporated and the mold is brought up to casting temperature (1350 f)
The proper amount of metal (silver) is weighed out and melted in the caster's crucible. The mold is taken directly from the kiln and put into the flask's cradle and the crucible is slid against it. The crucible has a hole in the end where the silver can pass from the crucible to the mold using g-force generated by a spring in the casting machine's base. When all is ready the catch or brake is released causing the caster to spin around like crazy pushing the metal from the crucible to the void in the mold where the wax used to be.
At the bottom of the coke can is a bear I carved from wax and cast today. I am also showing off my bitchen' torch.
Ah, toys. Oh yeah, dial up warning.