How to Make Cast Iron Molds

Updated November 21, 2016

The most common method used to cast metals is sandcasting. This process uses common silica sand to create a cast that you can pour molten iron into. Iron melts at between 1175 and 1290 degrees Celsius. Sand is one of the few materials that can withstand these high temperatures. Unlike most moulds, sand moulds are used once, then the sand is washed away when the molten iron has cooled. You can cast iron to make sculptures or save money by casting your own car parts.

Place the object you would like to cast on a clean surface. Choose an object that has a flat bottom for an open-pour mould. Find a wooden box that is slightly larger than the object. Hammer off the bottom of the box so that you are left with a wooden frame. Place the frame around your object.

Add water to a large batch of sand. You will want about a 1 to 4 ratio of water to sand. Add the water slowly and mix the sand with your hands to make sure it is evenly damp.

Shake a light coating of parting dust over the object to prevent the mould from sticking to it. Pour the damp sand into the screen colander, over the frame, to remove any large chunks. Add enough sand until the frame is overflowing.

Pack the sand down into the frame using a wooden block. Add more sand as needed until the sand is completely packed around the object. Run a yard stick over the top of the frame to level off the sand.

Turn the frame over. If you have packed the object securely, no sand will come out. Carefully pull the object out from the sand, leaving an impression.

Run your finger through the sand at the side of the impression to create a shallow channel.

Heat the sand using a blow torch. Run the torch over the sand to dry out the mould. Make sure the impression is thoroughly dried. If the sand begins to blacken, immediately remove the torch.

Pour the molten iron into the channel of the mould you created until the iron fills the mould. The channel will prevent the mould from being damaged by the iron.

Allow the iron to cool for about 10 minutes. Pour cool water slowly onto the sand to remove it from the around the iron. When the iron is completely cool, brush off the extra sand with a soft cloth.


Take safety precautions when pouring the molten iron. Where protective gloves and goggles to protect your skin and eyes.

Things You'll Need

  • Object to mould
  • Wooden box
  • Hammer
  • Parting dust
  • Silica sand
  • Water
  • Screen colander
  • Wood block
  • Yard stick
  • Blowtorch
  • Molten iron
  • Cloth
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