sand casting street signs


As you know if you’ve visited Capital StreetScapes’ web site, our products are made from aluminum, which is a recyclable material. The majority of the aluminum used to fashion the products we sell at Capital StreetScapes actually comes from recycled aluminum, also known as secondary aluminum. Recycled aluminum can be salvaged and reused while retaining the same physical properties and qualities as primary aluminum. Two processes are used to fashion this aluminum into the individual components we offer – sand casting and extrusion. Today’s lesson is on sand casting.

The procedure used for our casted products is called “green sand molding” (not because the sand is green – it’s actually black – but because it’s used while wet, like green wood is considered green because it’s moist). With this method the sand, which is mixed with clay, coal and water as binding agents, is packed in a two-piece wooden flask around the pattern to produce the mold, or a cavity (once the pattern is removed) in the shape of the pattern. A small access canal is incorporated into the design to allow the molten metal to be poured into the mold - after the metal cools inside the mold, the sand can be broken away to reveal the molded metal shape.

Sand casting is preferred for its low cost and the simplicity of its materials. Other casting methods produce smoother products, but are more expensive. The green sand used in sand casting leaves a slightly rough surface on the molded piece, which we think gives character to the look of our components.

Green sand molding is used for sand casting because the green sand holds its shape well when wet, creating a solid mold. One of the great things about this method is that no baking or chemical treatment is required to get the mold to its final state, so the cost and time between pattern and finished part is greatly diminished.

Civilized man has been casting metal objects for well over 5000 years. The casted products we offer, such as our ornamental bases and finials, build on this time-honored tradition but are also low-cost, durable and environmentally friendly, not to mention classically attractive. Give us a call for your next project!