How to Melt Metal for Casting

Heat metal until it's molten, then use it for casting projects.

Low-melting-temperature metals, such as lead, pewter and tin, melt under the heat of the focused flame of a blowtorch, but metals with higher melting temperatures, such as aluminum, silver and iron, require the more intense heat of the crucible furnace to melt. A crucible is an ancient casting tool, a container typically made of clay or ceramic capable of withstanding temperatures higher than the heat necessary to melt the metal it holds. The casting metal goes inside the crucible, which in turn goes inside the furnace heated to the appropriate temperature.

Things You'll Need

• Charcoal brick
• Clay-shaving tool
• Razor blade
• Low-melting-temperature metal
• Blowtorch
• Flint striker
• Casting mold
• Welding goggles
• Leather safety gloves
• Full body protection: pants, long-sleeve shirt and shoes
• Metal tongs
• High-melting-temperature metal
• Jewelry saw
• Axe
• Sledgehammer
• Casting mold
• Sandbox filled with sand
• Crucible
• Crucible furnace

Instructions

Melt Low-Melting-Temperature Metals

1. Hollow out a cup-shaped depression from the inside of the charcoal brick using the clay-shaving tool and the razor blade. Carve a channel from one side of the depression to the edge of the brick.

2. Place the small pieces of low-melting-temperature casting metal inside the depression and the charcoal brick. Place the brick on a fireproof surface such as cement. Arrange the blowtorch, flint striker and casting mold nearby. Put on the welding goggles and leather safety gloves.

3. Open the gas line of the torch and light it by striking the flint in front of the nozzle. The flame will have an outer cone, which is large and blue, and an inner cone, which is hotter than the outer cone and either white or yellow. Wash the inner cone of the flame over the metal until it's molten. Pick up the brick with the metal tongs and pour the molten metal through the carved channel into the casting mold.

Melt High-Melting-Temperature Metals

1. Cut or break the casting metal into small pieces small enough to fit inside the crucible or other container. Smaller pieces also require less time to heat to melting than larger pieces. Some jewelry supply manufacturers sell shaved silver, gold, bronze and copper to use in metal casting, but a jewelry saw will work to dismantle all four types of metal into crucible-sized bits. Use an axe or a sledgehammer to break apart cast iron to melt.

2. Place the casting mold upright in the sandbox. Put on welding goggles, leather safety gloves and full body protection. Place the metal inside the crucible, place a crucible inside the furnace and light the furnace to the appropriate temperature to melt the casting metal. Look into the crucible while wearing the welding goggles to see when the metal melts.

3. Remove the crucible from the furnace using the metal tongs. Pour the molten metal slowly and carefully into the casting mold. Replace the crucible inside the furnace, turn off the heat and allow the furnace and crucible to cool.

Tips & Warnings

• Looking into the crucible without using the welding goggles can cause vision damage.

• Molten metal can cause injury and even death -- always wear full body protection while casting and use extreme caution during a pour.

References

• "The Complete Metalsmith, An Illustrated Handbook"; Tim McCreight; 1991
• "Practical Blacksmithing and Metalworking"; Percy W. Blandford; 1988
• "The Charcoal Foundry"; David J. Gingery; 1983