Making a Sand Cast Bronze Sculpture

Here's a sculpture that I made a few years ago that combined cast and fabricated bronze. Bronze casting can be done in your back yard if you have a leaf blower and a small refractory furnace. Sand casting, in particular, is a fast and cheap way to cast metal.

Adding sand to the flask.  The flask can be made of metal or wood, must register well and be able to withstand the pressure of compacting the sand. 

This pattern is made of wax, but patterns are often made of wood. The pattern will later be removed from the mold and bronze will be poured in the cavity created from the pattern. 

The sand needs to be compacted to hold its shape when the pattern is removed. Use a tool to hand pack the sand around the form until it is super dense. 

After the bottom of the flask has been rammed, talc is dusted over the surface of the pattern and sand to act as a release agent. 

Put the flask together, sift sand over the pattern and evenly continue to add sand until the flask is full. 

Ram the hell out of it. Continue adding sand until it completely fills the flask. 

Run a straight edge along the top edge of the flask to remove any excess sand. 

Separate the mold and remove the pattern. If you did a good job, you'll get good detail and shape accuracy. If it falls apart, feh!

Channels, or "gates", need to be carved into the sand to give the bronze a way enter and fill the mold. 

After the gates are cut into the sand, put the flask back together and you're ready to pour. 

Heat the bronze to about 2,150 degrees Fahrenheit. Safety first!

Slowly fill the mold--this is the fun part. 

When cool, your bronze will easily separate from the sand but you'll need to clean it up a bit and maybe fix some imperfections in the casting. Sand blasting and wire brushing works great for making it pretty. Now you're ready to patina, or use the casting in a larger piece. 

Beginning to fabricate the geometry around the casting for a wall hanging sculpture. Start by tack welding the forms together. 

Keep tack welding until the entire piece is together. Then weld the whole mess up, dress the welds (if you want) and make it nice. 

Clean the metal and then apply heat and chemicals: in this case ferric nitrate, cuprice nitrate and ammonium sulfide. This part is a little bit voodoo. 

Wax the sculpture with a couple coats of carnuba based wax and, presto, you have a bronze sculpture. Good luck!