How to Make Metal Foam

Create sand balls with your hands from a mixture of silica sand, bentonite, dextrin and sodium silicate. The balls will eventually form the pores in the metal foam, so size them according to the size you want the pores to be, but keep the sand balls as uniform as possible. Try to make them all about the same size and shape.

Make a wooden box that measures 7 inches by 6.7 inches by 2.6 inches. Use green sand mold with 5 percent clay and 3.5 percent moisture to create the mold for the metal foam. Press the green sand mold against the sides of the wooden box to give the mold the shape of the box.

Place the sand balls inside the mold cavity and place the green sand mold inside a cast iron box that is 25 inches by 18 inches by 5 inches.

Bring the temperature of the furnace up to 2,516 degrees Fahrenheit, and melt cast iron with the following proportions: 3.34 percent carbon, 2.18 percent silicon, 0.56 percent manganese, 0.14 percent sulfur and 0.25 percent phosphorous.

Inoculate the cast iron with 0.2 percent barium and pour the molten cast iron into the mold. The molten cast iron will find its way around the sand balls and fill up any crevices. Allow the cast iron to cool completely until it is hard and cool.

Separate the poured mold from the clay and remove the sand. The cast iron foam has increased mechanical strength, works well for cooking and is lighter weight than solid cast iron.