Wednesday, August 12, 2015

The Eco-friendly Sand Casting Process

Sand casting creates metal works of art.


Ever wonder how people create a beautiful bronze work of art or a custom designed wrought iron gate? How are mass produced car parts made? Green sand casting does it all. Green sand casting is commonly used for casting a metal part or custom designed object. Metals utilized are bronze, brass, iron and aluminum. Green sand, according to Ruican Machinery Company, is comprised of washed sand, which is bonded with various natural clays, chemical additives and water.


Instructions


1. Clean the object you want to cast. Make sure that the item's surface is free of dirt and blemishes. You are about to create a mold that will duplicate every feature of the item you are trying to cast. The molding process utilizes two boxes filled with green sand that have matching molten metal pour holes. The top part of box is called a "cope" for the top part of the object. The bottom is called a "drag" for the other half of the object. After the impression or pattern has been made to both sides of the object, each side will attach back to back to create a a complete object.


2. Create a pattern of the item you want to cast by pressing one side into one of the green sand boxes. Place side two in the other box. Pressing the object into the wet green sand creates two separate cavities that have the exact shape, detail and size of the object to be cast. The compressed sand around the pattern will ensure it retains its shape for the rest of the casting process. You now have a mold ready for molten metal. Set aside the object.


3. Allow the green sand in both boxes to dry thoroughly overnight, until the moisture has evaporated. This makes sure that side one and side two patterns will remain in their shape, when they are attached together, before you pour molten metal.


4. Combine both halves of the boxes into one unit making sure that the molten metal pour hole is unobstructed.


5. Heat metal in a crucible. When molten, pour the liquid metal into the pattern's mold cavity through the pour hole.


6. Cool the molten metal in the mold, by allowing it to cool naturally to room temperature. This allow an even solidification of the metal.


7. Prepare the casted object for removal by vibrating the sand until it is released from around the casting. Open the box. Remove the metal casting for finishing.


8. Finish the final form of the object by trimming excess metal, sanding the surface, and polishing, if necessary, until shiny.