Step 1: Materials Needed
Other items you'll need are some molten aluminum and bronze metals, 1300 f and 2100 f respectivley. And some ladles to pour the metal.
Step 2: Making the Molds
Pour the sand into the drag portion of the pattern (bottom). Let it cure for 5 minutes, flip it over and tap it until the pattern comes loose leaving the bottom half of the mold. Repeat the process for the cope side (top).
Blow some air on both sides of the mold lightly to get rid of any loose sand or dirt. Align both sides of the mold and cover up the mold parting line to prevent metal from spilling out.
Step 3: Pouring the Metal
After pouring the metal, let the metal solidify and cool in the mold (1-3 hours). Once cool enough to handle, break it out of the mold and clean off the sand.
Step 4: Clean Up
Use a sanding wheel to clean up any flashing on the parting line. Go over twice, once with a sanding belt and again with scotchbright to clean the grinding marks and blend in.
I decided to use a lathe to give all my pieces a nice flat surface. 600 rpm did just nice for both materials. Once every piece has been turned, use a file to break the machined edge.
The last step is to to toss them in the Ol tumble blast for 1 minute to give it a nice surface finish.
Step 5: Finished Product
For those of you who don't have access to a foundry or a premade pattern, you could always design your own pattern and 3d print it. Plus there is a few good instructables out there on how to make a furnace. Molding material can be purchased online or improvised. Also, most foundries are not opposed to helping people out with projects if you ask them for materials or help as long as it is not in excess.