Sand casting is a vital procedure in metal casting where sand is used in the process of molding. Also referred to as sand molded casting, this process usually occurs in foundries which are specialized factories where metal casting occurs. It is not actually green in color but it is expendable mold that is made out of wet sand and is used to make the mold shape for green sand casting for metal.
In actual sense, green sand is not a kind of sand but a mixture of several ingredients. The following are the ingredients needed to make it for green sand casting:
- 1. Silica, chromite, zircon sand or graphite
- 2. bentonite clay, 5-11% is required.
- 3. 2% to 4% water
- 4. 3% to 5% inert sludge
- 5. 0% to 1 % anthracite
How to cast with green sandMaking a foundry at home is not a simple thing, there is need to observe safety precautions to prevent injuries.
First, you need to create a mold that can withstand heat and the pressure of molten metal while retaining its shape.
Make a square wooden box called a flask, fill it with green sand and ram it in the drag then sprinkle it with diatomaceous earth as a parting compound.
Others may use saw dust but the quality will be lower.
Poke a wire around the green sand to eliminate pockets of air and allow for steam to escape during casting.
Make a sprue using a sprue pin, then ram it and pull the sprue out.
Part the mold cleanly and you have a complete mold made from green sand casting.
Melt scrap metal such as aluminum using a small furnace or crucible, pour the molten metal in the sprue and close up the casting.
Give it 30 minutes to 1 hour to cool, lift of the top part of the greensand mold and voila! the metal cast is made.
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